“Which Arduino Board Should I choose ?”
Short Answer: Start With Arduino UNO…

Keywords: Selecting an Arduino, Which Arduino Should I Buy? , Which Arduino do you need ?, Comparison of Arduino Boards

Arduino is, a great robotic microcontroller platform for anyone interested in robots and robotics projects. One of the best things about it is that it’s undergoing constant innovation. There lots of different Arduino boardswhich you can use as your robot controller on the market, so you can find the perfect hardware for any kind of project you’re working on.

Unfortunately, that same huge selection of Arduino boards can make it hard for a beginner to get started with the platform.”Which Arduino Board Should I choose ?”  is the main question. On the official site alone, there are almost 20  Arduino boards listed, and there are dozens more unofficial boards for sale on other sites. Picking the one that’s exactly what you need is HARD—especially if you’re not familiar with the terms used to describe the various microcontrollers and boards.

To help make the process a little easier, we are going to look at the most common Arduino boards on the market right now, and we will explain how to distinguish between them.

3 BROAD WAYS to Differentiate the Various Arduino Boards:

A – Processing Capabilities : The first is to look at the board’s processing capabilities — the microcontroller’s memory, clockspeed, and bandwidth. The processing hardware is generally entirely determined by which microcontroller chip the board uses, and constrains what kinds of software can run on that board.

B- Feature Set: The second way to differentiate between the boards is their feature set. This includes all the stuff on the board other than the microcontroller, such as input and output pins, built-in hardware like Buttons and LEDs, and the interfaces available on the board (USB, Ethernet, etc).

C- Form Factor: Finally, because Arduino is meant to be built into physical projects, form factor is very important. Arduino comes a variety of shapes and sizes.

Now Let’s look at the boards you’re most likely to want to use in your project (as of Now 2013).  We’ll examine the distinguishing characteristics and features of each Arduino Board model.

1-ARDUINO UNO – Best for Beginners 

• Processor: ATmega328 (8-bit CPU, 16MHz clock speed, 2KB SRAM, 32KB flash storage)
• Features: 14 digital I/O pins, 6 analog input pins, removable microcontroller
• Form Factor: 2.7” x 2.1” (6,8 cm x 5,3 cm )rectangle
• Price: Around $30

The Arduino Uno is the most “standard” Arduino board currently on the market, and is probably the best choice for beginners just getting started with the platform. The board is compatible with more shields (add-on boards) than other models. Additionally, the ATmega328 microcontroller can be removed from its socket and replaced for as little as $6, in case you break it somehow.

The Uno’s main limitation is the ATmega328 chip, which doesn’t have a lot of SRAM or flash memory. That limits the kinds of programs you can load on the chip—if your project involves a display or otherwise needs to store and use any form of images or audio data, 2KB of memory probably isn’t going to be enough.

2-  ARDUINO LEONARDO – Slight Upgrade to the UNO, Built in USB 

• Processor: ATmega32u4 (8-bit CPU, 16MHz clock speed, 2.5KB SRAM, 32KB flash storage)
• Features: 20 digital I/O pins, 12 of which can be used as analog inputs, native USB support
• Form Factor: 2.7” x 2.1” (6,8 cm x 5,3 cm) rectangle
• Price: Around $25

The Leonardo is, essentially, a slight upgrade to the Uno. It looks a lot like the Uno, but it features a soldered-on ATmega32u4 microprocessor with a tiny bit more memory. The main advantage of the AtMega32u4 isn’t the extra SRAM, though, it’s the chip’s built-in USB compatibility. This allows the Leonardo to interface with a PC, which sees it as a generic mouse or keyboard. It also features a few extra analog input pins.

Most impressively? The Leonardo is actually cheaper than the Uno, at $25. Before you start hammering that “add to shopping cart” button, note that the general impression around the web seems to be that the Leonardo still has a few bugs that need ironing out, and isn’t quite as beginner friendly as the Uno. For builders already familiar with Arduino, this is the better deal.

3- ARDUINO DUE – For More Complicated Projects

• Processor: Atmel SAM3X8E ARM Cortex-M3 (32 bit CPU, 84MHz clock speed, 96KB SRAM, 512KB flash storage)
• Features: 54 digital I/O pins, 12 analog input pins, 2 analog output pins, native USB port
• Form factor: 4” x 2.1” (10 cm x 5,3 cm)  rectangle
• Price: Around $50

One of the newest Arduino boards, the Due is the heavy-hitter of the family, packing a 32-bit ARM processor that handily outclasses any of the processors found in other Arduino boards. The DUE is primarily for more complicated projects that can make use of its muscular processor, or that need more I/O pins than are found on the smaller Arduino boards. That said, the Due is substantially bigger and more expensive than the Uno or Leonardo, so consider whether you really need the extra power before making a purchase.

One drawback to the Due is that it operates at 3.3 volts, which is different than the 5 volts that most other Arduino boards operate at. That limits the add-on hardware that’s compatible with the Arduino Due—if an add-on board tries to send a 5 volt signal to the Due’s I/O pins, it could damage the microcontroller. If you need a powerful Arduino board that still operates at 5 volts, you can look at the $58 Arduino Mega 2560, but for the most purposes that board is outperformed by the cheaper DUE.

4- ARDUINO MICRO – Small form factor, Leonardo Performance

• Processor: ATmega32u4 (8-bit CPU, 16MHz clock speed, 2.5KB SRAM, 32KB flash storage)
• Features: 20 digital I/O pins, 12 of which can be used as analog inputs, native USB support
• Form Factor: 1.9” x 0.7” (4,8cm x  1,78 cm )rectangle
• Price: $27

For projects where size matters, there are a number of miniaturized boards to consider, including the Micro, Nano and Mini (and that’s just on the official Arduino site!). For most builders, the best choice is going to be the Arduino Micro, a new board that includes all of the power and functionality of a full-sized Arduino Leonardo board in a much smaller form factor.

Due to the small form factor, the Arduino Micro won’t work with many add-on boards, but it is designed to easily slot into a breadboard, for faster prototyping.

5- LILYPAD ARDUINO – For Flexible Fabric-Based Projects

• Processor: ATmega328 (8-bit CPU, 16MHz clock speed, 2KB SRAM, 32KB flash storage)
• Features: 14 digital I/O pins, 6 analog input pins
• Form Factor: 2” diameter circle
• Price: $22

The LilyPad is an Arduino board specifically designed for wearable devices. Its circular shape and standoff-less I/O pins are designed to make it easy to sew the LilyPad into fabric-based projects.

The hardware on a standard LilyPad board is basically the same as on and Arduino Uno. There are a number of other LilyPad options available as well, including the are a number of LilyPad boards available, including the LilyPad Arduino USB, which feature’s the Leonardo’s ATmega32u4 chip, the LilyPad Arduino Simple, which has fewer I/O connections than the basic model, and the LilyPad Arduino SimpleSnap, which can be snapped into and out of projects, so they can be safely washed.

6- ARDUINO ESPLORA – For Special Needs

• Processor: ATmega32u4 (8-bit CPU, 16MHz clock speed, 2.5KB SRAM, 32KB flash storage)
• Features: Lots of built-in input and output hardware
• Form Factor: 6.5” x 2.4” oval
• Price: $60

The Esplora is an Arduino board (based on the Leonardo hardware) that comes with a whole bunch of I/O hardware soldered directly to the board. On the input side you get a joystick, four buttons, a linear potentiometer (slider), a microphone, a light sensor, a temperature sensor and a three-axis accelerometer. For outputs, you get a buzzer, an RGB led, and a TFT display connector to attach a LCD screen (not included).

The tradeoff is that you do not get the standard set of digital and analog I/O pins, which allow you to wire up all sorts of hardware to your Arduino board. That sharply limits the kinds of projects you can make. The Arduino Esplora is best for people who want to learn to use the Arduino software to write programs that have access to a basic toolbox of I/O sources, without having to worry about the electronics side of things.

7- ARDUINO YUN – Linux-based system-on-a chip

• Processor: ATmega32u4 (8-bit CPU, 16MHz clock speed, 2.5KB SRAM, 32KB flash storage), Atheros AR9331 system on a chip
• Features: Wi-fi enabled Linux based system on a chip, 14 digital analog I/O pins, 12 of which can be used as analog inputs. Native USB.
• Form Factor: ~2.7” x 2.1” rectangle
• Price: $65, available at the end of June

The Yun is an attempt to make it easier to connect to cloud-based services from the Arduino platform. Typically, the low-bandwidth, low-memory microcontrollers have a hard time handling the verbose protocols used to access those services—to get around this limitation, the Yun features a separate Linux-based system-on-a chip on the motherboard. The Linux system takes care of the networking tasks, while you can use the ATmega32u4 like a standard Arduino Leonardo.

8- ARDUINO ROBOT – To  build your own, custom robot

• Processor: 2 x ATmega32u4 (8-bit CPU, 16MHz clock speed, 2.5KB SRAM, 32KB flash storage)
• Features: Wheels, 8 analogue input pins,6 digital I/O pins, LCD screen
• Form Factor: Two 7.5” diameter circles
• Price: $275, on sale online at the end of July.

At the risk of stating the obvious, the Arduino Robot is an Arduino board that’s also a little robot. It’s actually composed of two separate boards (a control board and a motor board) that each feature the Leonardo’s ATmega32u4 processor. The bottom board has a pair of wheels, space for 4 batteries, and infrared sensors. The top board has an LCD screen, 4 buttons, a speaker, a compass chip and some LEDs.

Though it’s designed with room to add your own custom hardware, the Arduino Robot is still more preconfigured than most Arduino boards. If you want to build your own, custom robot, you’ll have a lot more flexibility using an Uno or a Leonardo, along with a motor control shield and whatever motors, servos and actuators you want to use.

TECHNICAL DATA TABLE of Arduino Boards 

 ARDUINO BOARDS COMPARE

Glossary of Arduino and Microcontroller Terms:

uC (Microcontroller): The microcontroller is the heart (or, more appropriately, the brain) of the Arduino board. The Arduino development board is based on AVR microcontrollers of different types, each of which have different functions and features.

Input Voltage: This is the suggested input voltage range for the board. The board may be rated for a slightly higher maximum voltage but this is the safe operating range. A handy thing to keep in mind is that many of the Li-Po batteries that we carry are 3.7V meaning that any board with an input voltage including 3.7V can be powered directly from one of our Li-Po battery packs.

System Voltage: This is the system voltage of the board, i.e. the voltage that the microcontroller is actually running at. This is an important factor for shield-compatibility since the logic level is now 3.3V instead of 5V. You always want to be sure that whatever outside system with which you’re trying to communicate is able to match the logic level of your controller.

Clock Speed: This is the operating frequency of the microcontroller and is related to the speed at which it can execute commands. Although there are rare exceptions, most ATMega microcontrollers running at 3V will be clocked at 8MHz whereas most running at 5V will be clocked at 16MHz. The clock speed of the Arduino can be divided down for power savings with a few tricks if you know what you’re doing.

Digital I/O: This is the number of digital input/output pins that are broken out on the Arduino board. Each of these can be configured as either an input or an output, some are capable of PWM and some double as serial communication pins.

Analog Inputs: This is the number of analog input pins that are available on the Arduino board. Analog pins are labeled “A” followed by their number, they allow you to read analog values using the analog-to-digital converter (ADC) in the ATMega chip. Analog inputs can also be configured as more digital I/O if you need it!

PWM: This is the number of digital I/O pins that are capable of producing a PWM signal. A PWM signal is like an analog output, it allows your Arduino to “fake” an analog voltage between zero and the system voltage.

UART: This is the number of separate serial communication lines your Arduino board can support. On most Arduino boards, digital I/O pins 0&1 double as your serial send and receive pins and are shared with the serial programming port. Some Arduino boards have multiple UARTs and can support multiple serial ports at once. All Arduino boards have at least one UART for programming, but some aren’t broken out to pins that are accessible.

Flash Space: This is the amount of program memory that the chip has available for your to store your sketch. Not all of this memory is available as a very small portion is taken up by the bootloader (usually between 0.5 and 2KB).

Bootloader: If the microcontroller is the brain of the Arduino board, then the bootloader is its personality. Without the bootloader, it just wouldn’t be an Arduino. The bootloader lives on the ATMega chip and allows you to load programs through the serial port instead of having to use a hardware programmer. Because different Arduino board use different microcontrollers and programming interfaces, there are different bootloader programs on each. The source code for the bootloaders can be found in your Arduino distribution. All Arduino bootloaders will allow you to load code from the Arduino IDE.

Programming Interface: This is how you hook up the Arduino board to your computer for programming. Some boards have a USB jack on-board so that all you need to do is plug them into a USB cable, others have a header available so that you can plug in an FTDI Basic breakout or FTDI Cable. Other boards, like the Mini, break out the serial pins for programming but aren’t pin-compatible with the FTDI header. Any Arduino board that has a USB jack on-board also has some other hardware that enables the serial to USB conversion. Some boards, however, don’t need additional hardware because their microncontrollers have built-in support for USB.

Resources:

http://www.tested.com/tech/robots/456466-know-your-arduino-guide-most-common-boards/

http://arduino.cc/en/Products.Compare

The post Arduino Boards Comparison – Which Arduino Should I Choose ? appeared first on Robotpark ACADEMY.

One major drawback to working with motors is the large amounts of electrical noise they produce. This noise can interfere with your sensors and can even impair your microcontroller by causing voltage dips on your regulated power line. Large enough voltage dips can corrupt the data in microcontroller registers or cause the microcontroller to reset.

The main source of motor noise is the commutator brushes, which can bounce as the motor shaft rotates. This bouncing, when coupled with the inductance of the motor coils and motor leads, can lead to a lot of noise on your power line and can even induce noise in nearby lines.

There are several precautions you can take to help reduce the effects of motor noise on your system:

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1) Solder capacitors across your motor terminals. Capacitors are usually the most effective way to suppress motor noise, and as such we recommend you always solder at least one capacitor across your motor terminals. Typically you will want to use anywhere from one to three 0.1 µF ceramic capacitors, soldered as close to the motor casing as possible. For applications that require bidirectional motor control, it is very important that you do not use polarized capacitors!

If you use one capacitor, solder one lead to each of the motor’s two terminals as shown.

 

Note: For greater noise suppression, you can solder two capacitors to your motor, one from each motor terminal to the motor case.

Note: For the greatest noise suppression, you can solder in all three capacitors: one across the terminals and one from each terminal to the motor case.

2) Keep your motor and power leads as short as possible. You can decrease noise by twisting the motor leads so they spiral around each other.

3) Route your motor and power wires away from your signal lines. Your motor lines can induce currents in nearby signal lines. We have observed voltage spikes as high as 20 V induced in completely separate circuits near a noisy motor.

4) Place decoupling capacitors (also known as “bypass capacitors”) across power and ground near any electronics that you want to isolate from noise. The closer you can get them to the electronics, the more effective they will be, and generally speaking, the more capacitance you use, the better. We recommend using electrolytic capacitors of at least several hundred µF.

Note that electrolytic caps are polarized, so take care to install them with the negative lead connected to ground and the positive lead connected to VIN, and make sure you choose one with a voltage rating high enough to tolerate the noise spikes you are trying to suppress. A good rule of thumb is to select one that is rated for at least twice your input voltage.

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Resources:

 http://www.pololu.com/docs/0J15/9

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The post Dealing with Motor Noise of a Robot 51064 appeared first on Robotpark ACADEMY.

“Which Arduino Board Should I choose ?”
Short Answer: Start With Arduino UNO…

Keywords: Selecting an Arduino, Which Arduino Should I Buy? , Which Arduino do you need ?, Comparison of Arduino Boards

Arduino is, a great robotic microcontroller platform for anyone interested in robots and robotics projects. One of the best things about it is that it’s undergoing constant innovation. There lots of different Arduino boardswhich you can use as your robot controller on the market, so you can find the perfect hardware for any kind of project you’re working on.

Unfortunately, that same huge selection of Arduino boards can make it hard for a beginner to get started with the platform.”Which Arduino Board Should I choose ?”  is the main question. On the official site alone, there are almost 20  Arduino boards listed, and there are dozens more unofficial boards for sale on other sites. Picking the one that’s exactly what you need is HARD—especially if you’re not familiar with the terms used to describe the various microcontrollers and boards.

To help make the process a little easier, we are going to look at the most common Arduino boards on the market right now, and we will explain how to distinguish between them.

3 BROAD WAYS to Differentiate the Various Arduino Boards:

A – Processing Capabilities : The first is to look at the board’s processing capabilities — the microcontroller’s memory, clockspeed, and bandwidth. The processing hardware is generally entirely determined by which microcontroller chip the board uses, and constrains what kinds of software can run on that board.

B- Feature Set: The second way to differentiate between the boards is their feature set. This includes all the stuff on the board other than the microcontroller, such as input and output pins, built-in hardware like Buttons and LEDs, and the interfaces available on the board (USB, Ethernet, etc).

C- Form Factor: Finally, because Arduino is meant to be built into physical projects, form factor is very important. Arduino comes a variety of shapes and sizes.

Now Let’s look at the boards you’re most likely to want to use in your project (as of Now 2013).  We’ll examine the distinguishing characteristics and features of each Arduino Board model.

1-ARDUINO UNO

 Best for Beginners 

• Processor: ATmega328 (8-bit CPU, 16MHz clock speed, 2KB SRAM, 32KB flash storage)
• Features: 14 digital I/O pins, 6 analog input pins, removable microcontroller
• Form Factor: 2.7” x 2.1” (6,8 cm x 5,3 cm )rectangle
• Price: Around $30

The Arduino Uno is the most “standard” Arduino board currently on the market, and is probably the best choice for beginners just getting started with the platform. The board is compatible with more shields (add-on boards) than other models. Additionally, the ATmega328 microcontroller can be removed from its socket and replaced for as little as $6, in case you break it somehow.

The Uno’s main limitation is the ATmega328 chip, which doesn’t have a lot of SRAM or flash memory. That limits the kinds of programs you can load on the chip—if your project involves a display or otherwise needs to store and use any form of images or audio data, 2KB of memory probably isn’t going to be enough.

Go To Product Page

2-  ARDUINO LEONARDO

Slight Upgrade to the UNO, Built in USB 

• Processor: ATmega32u4 (8-bit CPU, 16MHz clock speed, 2.5KB SRAM, 32KB flash storage)
• Features: 20 digital I/O pins, 12 of which can be used as analog inputs, native USB support
• Form Factor: 2.7” x 2.1” (6,8 cm x 5,3 cm) rectangle
• Price: Around $25

The Leonardo is, essentially, a slight upgrade to the Uno. It looks a lot like the Uno, but it features a soldered-on ATmega32u4 microprocessor with a tiny bit more memory. The main advantage of the AtMega32u4 isn’t the extra SRAM, though, it’s the chip’s built-in USB compatibility. This allows the Leonardo to interface with a PC, which sees it as a generic mouse or keyboard. It also features a few extra analog input pins.

Most impressively? The Leonardo is actually cheaper than the Uno, at $25. Before you start hammering that “add to shopping cart” button, note that the general impression around the web seems to be that the Leonardo still has a few bugs that need ironing out, and isn’t quite as beginner friendly as the Uno. For builders already familiar with Arduino, this is the better deal.

Go To Product Page

3- ARDUINO DUE

For More Complicated Projects

• Processor: Atmel SAM3X8E ARM Cortex-M3 (32 bit CPU, 84MHz clock speed, 96KB SRAM, 512KB flash storage)
• Features: 54 digital I/O pins, 12 analog input pins, 2 analog output pins, native USB port
• Form factor: 4” x 2.1” (10 cm x 5,3 cm)  rectangle
• Price: Around $50

One of the newest Arduino boards, the Due is the heavy-hitter of the family, packing a 32-bit ARM processor that handily outclasses any of the processors found in other Arduino boards. The DUE is primarily for more complicated projects that can make use of its muscular processor, or that need more I/O pins than are found on the smaller Arduino boards. That said, the Due is substantially bigger and more expensive than the Uno or Leonardo, so consider whether you really need the extra power before making a purchase.

One drawback to the Due is that it operates at 3.3 volts, which is different than the 5 volts that most other Arduino boards operate at. That limits the add-on hardware that’s compatible with the Arduino Due—if an add-on board tries to send a 5 volt signal to the Due’s I/O pins, it could damage the microcontroller. If you need a powerful Arduino board that still operates at 5 volts, you can look at the $58 Arduino Mega 2560, but for the most purposes that board is outperformed by the cheaper DUE.

Go To Product Page

4- ARDUINO MICRO

Small form factor, Leonardo Performance

• Processor: ATmega32u4 (8-bit CPU, 16MHz clock speed, 2.5KB SRAM, 32KB flash storage)
• Features: 20 digital I/O pins, 12 of which can be used as analog inputs, native USB support
• Form Factor: 1.9” x 0.7” (4,8cm x  1,78 cm )rectangle
• Price: $27

For projects where size matters, there are a number of miniaturized boards to consider, including the Micro, Nano and Mini (and that’s just on the official Arduino site!). For most builders, the best choice is going to be the Arduino Micro, a new board that includes all of the power and functionality of a full-sized Arduino Leonardo board in a much smaller form factor.

Due to the small form factor, the Arduino Micro won’t work with many add-on boards, but it is designed to easily slot into a breadboard, for faster prototyping.

Go To Product Page

5- LILYPAD ARDUINO

For Flexible Fabric-Based Projects

• Processor: ATmega328 (8-bit CPU, 16MHz clock speed, 2KB SRAM, 32KB flash storage)
• Features: 14 digital I/O pins, 6 analog input pins
• Form Factor: 2” diameter circle
• Price: $22

The LilyPad is an Arduino board specifically designed for wearable devices. Its circular shape and standoff-less I/O pins are designed to make it easy to sew the LilyPad into fabric-based projects.

The hardware on a standard LilyPad board is basically the same as on and Arduino Uno. There are a number of other LilyPad options available as well, including the are a number of LilyPad boards available, including the LilyPad Arduino USB, which feature’s the Leonardo’s ATmega32u4 chip, the LilyPad Arduino Simple, which has fewer I/O connections than the basic model, and the LilyPad Arduino SimpleSnap, which can be snapped into and out of projects, so they can be safely washed.

Go To Product Page

6- ARDUINO ESPLORA

for Special Needs

• Processor: ATmega32u4 (8-bit CPU, 16MHz clock speed, 2.5KB SRAM, 32KB flash storage)
• Features: Lots of built-in input and output hardware
• Form Factor: 6.5” x 2.4” oval
• Price: $60

The Esplora is an Arduino board (based on the Leonardo hardware) that comes with a whole bunch of I/O hardware soldered directly to the board. On the input side you get a joystick, four buttons, a linear potentiometer (slider), a microphone, a light sensor, a temperature sensor and a three-axis accelerometer. For outputs, you get a buzzer, an RGB led, and a TFT display connector to attach a LCD screen (not included).

The tradeoff is that you do not get the standard set of digital and analog I/O pins, which allow you to wire up all sorts of hardware to your Arduino board. That sharply limits the kinds of projects you can make. The Arduino Esplora is best for people who want to learn to use the Arduino software to write programs that have access to a basic toolbox of I/O sources, without having to worry about the electronics side of things.

Go To Product Page

7- ARDUINO YUN

Linux-based system-on-a chip

• Processor: ATmega32u4 (8-bit CPU, 16MHz clock speed, 2.5KB SRAM, 32KB flash storage), Atheros AR9331 system on a chip
• Features: Wi-fi enabled Linux based system on a chip, 14 digital analog I/O pins, 12 of which can be used as analog inputs. Native USB.
• Form Factor: ~2.7” x 2.1” rectangle
• Price: $65, available at the end of June

The Yun is an attempt to make it easier to connect to cloud-based services from the Arduino platform. Typically, the low-bandwidth, low-memory microcontrollers have a hard time handling the verbose protocols used to access those services—to get around this limitation, the Yun features a separate Linux-based system-on-a chip on the motherboard. The Linux system takes care of the networking tasks, while you can use the ATmega32u4 like a standard Arduino Leonardo.

Go To Product Page

8- ARDUINO ROBOT

 To  build your own, custom Robot

• Processor: 2 x ATmega32u4 (8-bit CPU, 16MHz clock speed, 2.5KB SRAM, 32KB flash storage)
• Features: Wheels, 8 analogue input pins,6 digital I/O pins, LCD screen
• Form Factor: Two 7.5” diameter circles
• Price: $275, on sale online at the end of July.

At the risk of stating the obvious, the Arduino Robot is an Arduino board that’s also a little robot. It’s actually composed of two separate boards (a control board and a motor board) that each feature the Leonardo’s ATmega32u4 processor. The bottom board has a pair of wheels, space for 4 batteries, and infrared sensors. The top board has an LCD screen, 4 buttons, a speaker, a compass chip and some LEDs.

Though it’s designed with room to add your own custom hardware, the Arduino Robot is still more preconfigured than most Arduino boards. If you want to build your own, custom robot, you’ll have a lot more flexibility using an Uno or a Leonardo, along with a motor control shield and whatever motors, servos and actuators you want to use.

Go To Product Page

TECHNICAL DATA TABLE of Arduino Boards 

 ARDUINO BOARDS COMPARE

Glossary of Arduino and Microcontroller Terms:

uC (Microcontroller): The microcontroller is the heart (or, more appropriately, the brain) of the Arduino board. The Arduino development board is based on AVR microcontrollers of different types, each of which have different functions and features.

Input Voltage: This is the suggested input voltage range for the board. The board may be rated for a slightly higher maximum voltage but this is the safe operating range. A handy thing to keep in mind is that many of the Li-Po batteries that we carry are 3.7V meaning that any board with an input voltage including 3.7V can be powered directly from one of our Li-Po battery packs.

System Voltage: This is the system voltage of the board, i.e. the voltage that the microcontroller is actually running at. This is an important factor for shield-compatibility since the logic level is now 3.3V instead of 5V. You always want to be sure that whatever outside system with which you’re trying to communicate is able to match the logic level of your controller.

Clock Speed: This is the operating frequency of the microcontroller and is related to the speed at which it can execute commands. Although there are rare exceptions, most ATMega microcontrollers running at 3V will be clocked at 8MHz whereas most running at 5V will be clocked at 16MHz. The clock speed of the Arduino can be divided down for power savings with a few tricks if you know what you’re doing.

Digital I/O: This is the number of digital input/output pins that are broken out on the Arduino board. Each of these can be configured as either an input or an output, some are capable of PWM and some double as serial communication pins.

Analog Inputs: This is the number of analog input pins that are available on the Arduino board. Analog pins are labeled “A” followed by their number, they allow you to read analog values using the analog-to-digital converter (ADC) in the ATMega chip. Analog inputs can also be configured as more digital I/O if you need it!

PWM: This is the number of digital I/O pins that are capable of producing a PWM signal. A PWM signal is like an analog output, it allows your Arduino to “fake” an analog voltage between zero and the system voltage.

UART: This is the number of separate serial communication lines your Arduino board can support. On most Arduino boards, digital I/O pins 0&1 double as your serial send and receive pins and are shared with the serial programming port. Some Arduino boards have multiple UARTs and can support multiple serial ports at once. All Arduino boards have at least one UART for programming, but some aren’t broken out to pins that are accessible.

Flash Space: This is the amount of program memory that the chip has available for your to store your sketch. Not all of this memory is available as a very small portion is taken up by the bootloader (usually between 0.5 and 2KB).

Bootloader: If the microcontroller is the brain of the Arduino board, then the bootloader is its personality. Without the bootloader, it just wouldn’t be an Arduino. The bootloader lives on the ATMega chip and allows you to load programs through the serial port instead of having to use a hardware programmer. Because different Arduino board use different microcontrollers and programming interfaces, there are different bootloader programs on each. The source code for the bootloaders can be found in your Arduino distribution. All Arduino bootloaders will allow you to load code from the Arduino IDE.

Programming Interface: This is how you hook up the Arduino board to your computer for programming. Some boards have a USB jack on-board so that all you need to do is plug them into a USB cable, others have a header available so that you can plug in an FTDI Basic breakout or FTDI Cable. Other boards, like the Mini, break out the serial pins for programming but aren’t pin-compatible with the FTDI header. Any Arduino board that has a USB jack on-board also has some other hardware that enables the serial to USB conversion. Some boards, however, don’t need additional hardware because their microncontrollers have built-in support for USB.

Resources:

http://www.tested.com/tech/robots/456466-know-your-arduino-guide-most-common-boards/

http://arduino.cc/en/Products.Compare

The post Comparison of Arduino Boards – 51063 appeared first on Robotpark ACADEMY.

You can Download the Source Codes of Tutorials Here : 51062 -Arduino Tutorials.zip

Arduino Tutorial 1: Uno Hardware 

(Basic Level)

In this video we will look at the hardware for the Arduino Uno.

Download Arduino IDE: http://arduino.cc/en/Main/Software

Arduino Tutorial #2: Getting Started

(Basic Level)

In our second Arduino tutorial, we take a look at what is essentially the “hello world” of the microcontroller world.  We go through the setup of the Arduino IDE and drivers, along with the programming. Connection with the usb port.

Arduino Tutorial #3: Digital Inputs and Pull-Up Resitors 

(Basic Level)

In this tutorial we go over using digital inputs with the arduino to turn on an LED whenever a button is pressed. We also discuss the evil that is the floating pin and how to solve it.

Arduino Tutorial #4: Serial Communication 

(Intermediate Level)

In this Arduino tutorial, we go over the Uno’s built in serial communication. We look at talking to the Arduino from the computer and vice versa, the difference between print and write, and my trick to getting the Arduino to accept strings of data, rather than just characters. Sending Commands to computer,

Arduino Tutorial #5: PWM and Servos 

(Intermediate Level)

Inthis Arduino Tutorial, we look at the pulse width modulation, PWM, pins on the Arduino and their various applications, including producing a pseudo-analog signal and controlling a servo. You can control a servo of a robot or a robotic project with arduino code.

Arduino Tutorial #6: Analog Input 

(Intermediate Level)

In this Arduino tutorial, we examine the use of the analog input pins, how they work, and how they are configured and used. As mentioned in the video, I have really come to the end of the basics of the Arduino.

Arduino Tutorial #7: External Pin Interrupt 

(Advanced Level)

In this Arduino Tutorial we discuss the basics of interrupts, their applications, and, more specifically, external pin interrupts.

Arduino Tutorial #8: I2C Communication

(Advanced Level)

This Arduino tutorial covers using I2C to communicate with an EEPROM chip. This is only part one of the I2C videos, there will be another covering Arduino to Arduino communication as well.

Arduino Tutorial #9: Leonardo vs. Uno 

(Basic Level)

Differences between Uno and Leonardo

Arduino Tutorial #10: Arduino to Arduino I2C

(Advanced Level)

In this tutorial, we continue with the second part of the Arduino I2C communication tutorial, using I2C to communicate between two Arduinos.

Arduino Tutorial #11: Leonardo as Keyboard

(Basic Level)

In this Arduino tutorial, we look at the Arduino Leonardo’s built in USB emulation capabilities. Specifically, generating keyboard output. Remember that it is a good idea to add a switch to your code to ensure that the board stops acting like a keyboard, so that it can be reprogrammed.

Arduino Tutorial #12: Wireless Communication

(Intermediate Level)

In today’s Arduino Tutorial, we explore using “5 dollar” transmitters and receivers to send data between two Arduinos without wires.
You can find the VirtualWire library here: http://www.airspayce.com/mikem/arduino/VirtualWire/

Arduino Tutorial #13: Internal EEPROM

(Intermediate Level)

In this Arduino Tutorial, we look at using the internal EEPROM included on the ATmega328p

Arduino Tutorial #14: Leonardo as Mouse

(Basic Level)

In this Arduino tutorial, we examine a more mischievous use for the Arduino Leonardo’s mouse emulation ability.

Arduino Tutorial #15: Controlling Motors

(Basic Level)

In this Arduino Tutorial, we use the ULN2003a IC to control a motor.

Arduino Tutorial #16: Simple SPI Communication

In this Arduino Tutorial, we look at using a shift register to demonstrate the Arduino’s simpler SPI communication.

DOWNLOAD:

You can Download the Source Codes of Tutorials Here : 51062 -Arduino Tutorials.zip

The post Arduino Tutorial Series – Basics of Arduino 51062 appeared first on Robotpark ACADEMY.

GETTING STARTED AND CONNECTED!

The first Arduino tutorial on getting started and connecting it to your PC. In this video I cover the following:

-What is Arduino?
-What is a sketch?
-What is the Arduino (software) IDE (interactive development environment) arduino-1.0.1
-Arduino philosophy
-We take a look at the Arduno hardware.
-I cover how to download the Arduino Software and drivers and then how to install them.
-What happens when the Arduino USB device driver fails and how to solve it.
-I upload a sketch to the Arduino UNO R3 to test it and blink an LED.
-I discuss the project for tutorial #2, a voltmeter with Min Max Ave.
-I talk about the Sparkfun serial enabled 16 x 2 LCD and the challenges it poses.

Arduino Uno R3 features:  ATmega328 micro controller, Input voltage – 7-12V, 14 Digital I/O Pins (6 PWM outputs), 6 Analogue Inputs, 32k Flash Memory , 16Mhz Clock Speed

Video Link - http://youtu.be/kLd_JyvKV4Y

Arduino Tutorial #2

SKETCH STRUCTURE, Variables, Procedures

In this Arduino tutorial we look at Sketch structure, variables and procedures.

* What is the sketch structure?
* What are variables and what types of variables – int, integer, float, floating point, byte, string array.
* The build of the voltage divider for the voltmeter can be found in the Ohms law tutorial:
http://www.youtube.com/watch?v=AWLJAD…
* What is the Arduino (software) IDE (interactive development environment) arduino-1.0.1
* What is an Arduino library / libraries
* Arduino philosophy
* We take a look at the Arduno hardware.
* I discuss the project for the tutorial, a voltmeter with Min Max Ave.
* I talk about the Sparkfun serial enabled 16 x 2 LCD and the challenges it poses.
* I talk about the Sparkfun serial enabled 20 x 4 LCD.
* Arduino for beginners / dummies / newbies

Arduino Site: http://www.arduino.cc/
Arduino software / IDE: http://arduino.cc/en/Main/Software
Arduino forum: http://arduino.cc/forum/

Video Link - http://youtu.be/Ub_oYlCo3i0

Arduino Tutorial #3

Functions, Return Values, Variables

A tutorial on sketch structure, functions, return values and variables.

Items and topics covered in this video:

* Local and global variables
* Functions / procedures
* Return values from functions
* Sample sketch code that does Math / arithmetic and write to the terminal
* Some commands used: Serial.print; Serial.println, if, else, void setup, void loop, return

Video Link: http://youtu.be/kV7FKL9FtwM

Arduino Tutorial #4

LCD Displays, Libraries 

A tutorial on interfacing LCDs (liquid crystal displays) with Arduino. We take a look at libraries and the role they play…and the potential issues, errors and troubleshooting involved. We look at several types of displays but concentrate on the 4×20 Sparkfun serial enabled LCD display.

Video Link: http://youtu.be/X1BCvjxIDHM

Arduino Tutorial #5

Digital Voltmeter, Analog to Digital Converter

In this tutorial we look at a digital voltmeter project and how it used the Arduino analog input. This involves understanding ADC or analog to digital converters and how they work.

The Arduino Due is a microcontroller board based on the Atmel SAM3X8E ARM Cortex-M3 CPU (datasheet). It is the first Arduino board based on a 32-bit ARM core microcontroller. It has 54 digital input/output pins (of which 12 can be used as PWM outputs), 12 analog inputs, 4 UARTs (hardware serial ports), a 84 MHz clock, an USB OTG capable connection, 2 DAC (digital to analog), 2 TWI, a power jack, an SPI header, a JTAG header, a reset button and an erase button.

Video Link: http://youtu.be/y-_Pkw_GQ-c

Resources

We also gave a quick peek at the Arduino DUE: http://arduino.cc/en/Main/arduinoBoar…
Thanks to Clarence of “Clarence’s Wicked Mind” for the original code that I used and updated for this project: http://www.clarenceho.net:8123/blog/a…
The sketch / project code for the digital voltmeter:: http://mjlorton.com/forum/index.php?t…
Also read Measuring Stuff – The Arduino DAQ Chronicles: https://sites.google.com/site/measuri…

The post Arduino VIDEO TUTORIALS 51061 appeared first on Robotpark ACADEMY.

Technical Specifications of Basic Stamp

Although the BASIC Stamp has the form of a DIP chip, it is in fact a small printed circuit board (PCB) that contains the essential elements of a microprocessor system:

• A Microcontroller containing the CPU, a built in ROM containing the BASIC interpreter, and various peripherals
• Memory (an i²C EEPROM)
• A clock, usually in the form of a ceramic resonator
• A power supply
• External input and output

The end result is that a hobbyist can connect a 9 V battery to a BASIC Stamp and have a complete system. A connection to a personal computer allows the programmer to download software to the BASIC Stamp, which is stored in the onboard non-volatile memory device: it remains programmed until it is erased or reprogrammed, even when the power is removed.

Programming Language

The BASIC Stamp is programmed in a variant of the BASIC language, called PBASIC. PBASIC incorporates common microcontroller functions, including PWM, serial communications, I²C and 1-Wire communications, communications with common LCD driver circuits, hobby servo pulse trains, pseudo-sine wave frequencies, and the ability to time an RC circuit which may be used to detect an analog value.

Once the program has been written, it is tokenized and sent to the chip through a serial cable.

 BASIC STAMP FAQS

Download PDF - 51060-Basic_Stamp_FAQ.pdf

Resources

http://www.pololu.com/file/download/basicstampfaq.pdf?file_id=0J201

The post What is the BASIC STAMP ? 51060 appeared first on Robotpark ACADEMY.

A microcontroller (sometimes abbreviated µC, uC or MCU) is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM. Microcontrollers are designed for embedded applications, in contrast to the microprocessors used in personal computers or other general purpose applications.

Microcontrollers are used in automatically controlled products and devices, such as automobile engine control systems, implantable medical devices, remote controls, office machines, appliances, power tools,robots and other embedded systems. By reducing the size and cost compared to a design that uses a separate microprocessor, memory, and input/output devices, microcontrollers make it economical to digitally control even more devices and processes.

Some microcontrollers may use 4-bit words and operate at clock rate frequencies as low as 4 kHz, for low power consumption (single-digit milliwatts or microwatts). They will generally have the ability to retain functionality while waiting for an event such as a button press or other interrupt; power consumption while sleeping (CPU clock and most peripherals off) may be just nanowatts, making many of them well suited for long lasting battery applications. Other microcontrollers may serve performance-critical roles, where they may need to act more like a digital signal processor (DSP), with higher clock speeds and power consumption.

A micro-controller is a single integrated circuit, commonly with the following features:

• central processing unit – ranging from small and simple 4-bit processors to complex 32- or 64-bit processors
• volatile memory (RAM) for data storage
• ROM, EPROM, EEPROM or Flash memory for program and operating parameter storage
• discrete input and output bits, allowing control or detection of the logic state of an individual package pin
• serial input/output such as serial ports (UARTs)
• other serial communications interfaces like I²C, Serial Peripheral Interface and Controller Area Network for system interconnect
• peripherals such as timers, event counters, PWM generators, and watchdog
• clock generator – often an oscillator for a quartz timing crystal, resonator or RC circuit
• many include analog-to-digital converters, some include digital-to-analog converters
• in-circuit programming and debugging support

Embedded Design:

A microcontroller can be considered a self-contained system with a processor, memory and peripherals and can be used as an embedded system.The majority of microcontrollers in use today are embedded in other machinery, such as automobiles, telephones, appliances, and peripherals for computer systems.

While some embedded systems are very sophisticated, many have minimal requirements for memory and program length, with no operating system, and low software complexity. Typical input and output devices include switches, relays,solenoids, LEDs, small or custom LCD displays, radio frequency devices, and sensors for data such as temperature, humidity, light level etc. Embedded systems usually have no keyboard, screen, disks, printers, or other recognizable I/O devices of a personal computer, and may lack human interaction devices of any kind.

Interrupts:

Microcontrollers must provide real time (predictable, though not necessarily fast) response to events in the embedded system they are controlling. When certain events occur, an interrupt system can signal the processor to suspend processing the current instruction sequence and to begin an interrupt service routine (ISR, or “interrupt handler”). The ISR will perform any processing required based on the source of the interrupt, before returning to the original instruction sequence. Possible interrupt sources are device dependent, and often include events such as

• an internal timer overflow,
• completing an analog to digital conversion,
• a logic level change on an input such as from a button being pressed,
• and data received on a communication link.

Where power consumption is important as in battery operated devices, interrupts may also wake a microcontroller from a low power sleep state where the processor is halted until required to do something by a peripheral event.

Programs:

Typically microcontroller programs must fit in the available on-chip program memory, since it would be costly to provide a system with external, expandable, memory. Compilers and assemblers are used to convert high-level language and assembler language codes into a compact machine code for storage in the microcontroller’s memory. Depending on the device, the program memory may be permanent, read-only memory that can only be programmed at the factory, or program memory that may be field-alterable flash or erasable read-only memory.

Other Microcontroller Features:

Microcontrollers usually contain from several to dozens of general purpose input/output pins (GPIO). GPIO pins are software configurable to either an input or an output state. When GPIO pins are configured to an input state, they are often used to read sensors or external signals. Configured to the output state, GPIO pins can drive external devices such as LEDs or motors.

Many embedded systems need to read sensors that produce analog signals. This is the purpose of the analog-to-digital converter (ADC). Since processors are built to interpret and process digital data, i.e. 1s and 0s, they are not able to do anything with the analog signals that may be sent to it by a device. So the analog to digital converter is used to convert the incoming data into a form that the processor can recognize. A less common feature on some microcontrollers is a digital-to-analog converter (DAC) that allows the processor to output analog signals or voltage levels.

In addition to the converters, many embedded microprocessors include a variety of timers as well. One of the most common types of timers is the Programmable Interval Timer (PIT). A PIT may either count down from some value to zero, or up to the capacity of the count register, overflowing to zero. Once it reaches zero, it sends an interrupt to the processor indicating that it has finished counting. This is useful for devices such as thermostats, which periodically test the temperature around them to see if they need to turn the air conditioner on, the heater on, etc.

A dedicated Pulse Width Modulation (PWM) block makes it possible for the CPU to control power converters, resistive loads, motors, etc., without using lots of CPU resources in tight timer loops.

Universal Asynchronous Receiver/Transmitter (UART) block makes it possible to receive and transmit data over a serial line with very little load on the CPU. Dedicated on-chip hardware also often includes capabilities to communicate with other devices (chips) in digital formats such as I²C and Serial Peripheral Interface (SPI).

Microcontrollers Vs Computers

A microcontroller is a computer. All computers — whether we are talking about a personal desktop computer or a large mainframe computer or a microcontroller — have several things in common:

• All computers have a CPU (central processing unit) that executes programs.
• The computer has some RAM (random-access memory) where it can store “variables.”
• And the computer has some input and output devices so it can talk to people. On your desktop machine, the keyboard and mouse are input devices and the monitor and printer are output devices. A hard disk is an I/O device — it handles both input and output.

The desktop computer you are using is a “general purpose computer” that can run any of thousands of programs. Microcontrollers are “special purpose computers.” Microcontrollers do one thing well. There are a number of other common characteristics that define microcontrollers. If a computer matches a majority of these characteristics, then you can call it a “microcontroller”:

• Microcontrollers are “embedded” inside some other device (often a consumer product).
• Another name for a microcontroller, therefore, is “embedded controller.”
• Microcontrollers are dedicated to one task and run one specific program.
• The program is stored in ROM(read-only memory) and generally does not change.
• Microcontrollers are often low-power devices.
• A desktop computer is almost always plugged into a wall socket and might consume 50 watts of electricity. A battery-operated microcontroller might consume 50 milliwatts.
• A microcontroller has a dedicated input device and often (but not always) has a small LED or LCD display for output.
• A microcontroller also takes input from the device it is controlling and controls the device by sending signals to different components in the device. (For Example : A microwave oven controller takes input from a keypad, displays output on an LCD display and controls a relay that turns the microwave generator on and off.)
• A microcontroller is often small and low cost. The components are chosen to minimize size and to be as inexpensive as possible.
• A microcontroller is often, but not always, ruggedized in some way. The microcontroller controlling a car’s engine, for example, has to work in temperature extremes that a normal computer generally cannot handle. A car’s microcontroller in Alaska has to work fine in -30 degree F (-34 C) weather, while the same microcontroller in Nevada might be operating at 120 degrees F (49 C). When you add the heat naturally generated by the engine, the temperature can go as high as 150 or 180 degrees F (65-80 C) in the engine compartment. On the other hand, a microcontroller embedded inside a VCR hasn’t been ruggedized at all.

Processor - The processor refers to the Central Processing Unit (CPU) of the microcontroller. It contains the Arithmetic Logic Unit (ALU), Control Unit, Instruction Decoder and some Special Registers (Stack Pointer, Status Register, Program Counter, etc.).

Volatile Memory - This is memory used by ht microcontroller for temporary data storage, system setup and peripherals configurations. Memory in this category includes SRAM and DRAM. AVR microcontrollers utilize SRAM.

Non-Volatile Memory - This is memory used by the microcontroller to store programs. Data can also be stored in this memory but the access time is much slower than that of RAM. Memory in this category includes ROM, PROM, EPROM, EEPROM and FLASH. The AVR microcontrollers utilize Flash for program storage, some AVR controllers contains a bit of EEPROM as well.

Timer Module - Most microcontrollers have at least one timer/counter peripheral. Timer/Counter modules are used to perform timing or counting operations in the controller. These include time stamping, measuring intervals, counting events, etc.

Interrupt Module - Interrupts enable the microcontroller to monitor certain events in the background while executing and application program and react to the event if necessary pausing the original program. This is all coordinated by the interrupt module.

Digital I/O Module - This module allows digital/logic communication with the microcontroller and the external world. Communication signals are that of TTL or CMOS logic.

Analog I/O Modules - These modules are use to input/output analog information from/to the external world. Analog modules include Analog Comparators and Analog-to-Digital Converters.

Serial Modules - These modules are used for serial communication with the external world. An example is the USART peripherial which utilizes the RS232 standard.

Microcontrollers Lesson – INTRODUCTION to Microcontrollers:

Table of Contents:

0:00 Introduction
0:38 What is it?
1:55 Where do you find them?
3:00 History
6:03 Microcontrollers vs Microprocessors
13:40 Basic Principles of Operation
15:29 Programming
18:23 Analog to Digital Converter
23:39 ADC Example- Digital Thermometer
29:34 Digital to Analog Converter
31:30 Microcontroller Applications
34:38 Packages
38:38 How to get started

Download Presentation - PowerPoint File

Resources:

Youtube Video – http://www.youtube.com/watch?v=CmvUY4S0UbI

http://en.wikipedia.org/wiki/Microcontroller

http://electronics.howstuffworks.com/microcontroller1.htm

http://www.mikroe.com/chapters/view/64/chapter-1-introduction-to-microcontrollers/

http://embeddedsystem.co.in/?cat=1

http://www.avr-tutorials.com/general/microcontrollers-basics

The post What is a Microcontroller ? 51059 appeared first on Robotpark ACADEMY.

The Handy Board is a popular handheld robotics controller. The Handy Board was developed at MIT by Fred G. Martin, and was closely based on a previous controller designed by Martin and Randy Sargent for the MIT LEGO Robot Contest. The Handy Board design is licensed free of charge. Thus, several manufacturers make Handy Boards. The Handy Board is used by hundreds of schools worldwide and by many hobbyists for their robot projects.

Handy Board Specs

– 68HC11 8-bit microcontroller @ 2 MHz
– 32KB battery-backed SRAM
– 2×16 LCD character display
– Support for four 1A motors
– 6 Servo motor controllers
– 7 Digital and 9 Analog inputs
- 8 Digital and 16 Analog outputs
- Infrared I/O capabilities
– Serial interface capabilities
– Sound output
– 11 cm x 8.5 cm x 5.25 cm (lxwxh – with battery, expansion board, and lcd screen)

 Download – Handy Board Manual PDF

VIDEO – Light Controlled Handyboard Cricket

Handyboard Lego Robot Line Following

HANDY BOARD QUESTIONS ?

How can I choose between the RCX and the Handy Board?

-The great strength of the LEGO Mindstorms system and its RCX brick is that it genuinely an everything-included, out-of-the box robotics building system. When you buy the Robotic Invention System, you get the RCX brick controller, motors, sensors, a big kit of LEGO, software, and everything else to make it all work.

-The Handy Board is more suitable when you don’t mind a little soldering to build your sensors and motors, but want something more expandable and with more inputs and outputs.

-To compare, the Handy Board can drive 4 motors and has direct inputs for 16 sensors, while the RCX brick does 3 motors and 3 sensors.

-The Handy Board’s design is open and fully documented; it is much easier to connect your own unique hardware to the Handy Board than it is to the RCX.

-The design of the RCX brick has been reverse-engineered and published by hobbyists, but it is still fairly tricky to connect unusual hardware to the RCX and then write software drivers to make that hardware work.

-The Handy Board is more expensive than the RCX: A Handy Board costs $200 to $300 for the assembled/tested board alone, while $200 buys you a Mindstorms RCX brick, plus 2 motors, 3 sensors, and a kit of 700+ LEGO pieces.

What kinds of motors are compatible with the Handy Board?

-The Handy Board is designed for motors that will operate at 9 volts and draw up to 1 ampere of current maximum. This includes all of the motors sold by the LEGO Group (the 9v standard motor, 9v gear motor, and 9v micro motor) and a variety of hobby motors.

-A motor draws its maximum amount of current when it is stalled (this is sometimes referred to as the “stall current”). A good way to get an estimate of how much current this will be at the Handy Board’s rated 9v supply level is to measure the motor’s resistance using a standard VOM (volt-ohm meter), and apply the Ohm’s Law formula current = voltage divided by resistance. Set the meter to its most sensitive resistance scale (typically, 0 to 200 ohms), apply the probes to the motor terminals, and gently rotate the motor shaft by hand until you obtain the smallest possible reading. The idea is to find the static position of the shaft that gives you the lowest ohmage reading and take that as the measurement.

-If this reading is nine ohms or more, then the motor should be compatible with the Handy Board. (At 9 volts, a 9 ohm reading would mean a current draw of one amp, the maximum the Handy Board can deliver.) If the reading is less than four ohms, the motor will probably draw too much current and won’t work.

-Please be aware that the Handy Board is not compatible with 3v to 4.5v motors found in many toy cars. These inexpensive motors are extremely noisy from an electrical standpoint; also, they typically will draw several amperes of current, thereby overloading the Handy Board’s motor drivers and causing the board to reset.

-The Handy Board also is not compatible with motors used in high end radio control cars. These motors are designed to draw huge amounts of power—25, 50, or more amperes of current.

How many servo motors can I drive from the Handy Board?

-The Handy Board itself comes with drivers to run two servo motors. With the Expansion Board, the Handy Board can run six servo motors.

Resources:

http://en.wikipedia.org/wiki/Handy_Board

http://handyboard.com/oldhb/faq/display-all.phtml#whyhb

http://handyboard.com/

The post What is Handy Board ? 51058 appeared first on Robotpark ACADEMY.

Simple Servos are used for positioning applications. They were originally designed to control Remote Control airplanes and their low cost and high torque makes them very useful as an actuator in prototyping applications. An RC Servo can be instructed to move to a desired position by the controller. Internally, it monitors the current position, and drives the motor as fast as it can until it reaches the desired position. This is a very cheap and simple way to control a motor. It has some limitations – there is no way for the controller to know the current position and speed of the motor. Applications that want smooth movement suffer from the aggressive acceleration.

Servo motors have been around for a long time and are utilized in many applications. They are small in size but pack a big punch and are very energy-efficient. Because of these features, they can be used to operate remote-controlled or radio-controlled toy cars, robots and airplanes. Servo motors are also used in industrial applications, robotics, in-line manufacturing,pharmaceutics and food services.

A Servo Motor is a rotary actuator that allows for precise control of angular position, velocity and acceleration. It consists of a suitable motor coupled to a sensor for position feedback. It also requires a relatively sophisticated controller, often a dedicated module designed specifically for use with servomotors.

Servo motors are not a different class of motor, on the basis of fundamental operating principle, but uses servo mechanism to achieve closed loop control with a generic open loop motor. Servo motors are used in applications such as robotics, CNC machinery or automated manufacturing.

SERVO MECHANISM

As the name suggests, a servomotor is a servo mechanism. More specifically, it is a closed-loop servo mechanism that uses position feedback to control its motion and final position. The input to its control is some signal, either analogue or digital, representing the position commanded for the output shaft.

The motor is paired with some type of encoder to provide position and speed feedback. In the simplest case, only the position is measured. The measured position of the output is compared to the command position, the external input to the controller. If the output position differs from that required, an error signal is generated which then causes the motor to rotate in either direction, as needed to bring the output shaft to the appropriate position. As the positions approach, the error signal reduces to zero and the motor stops.

The very simplest servo motors use position-only sensing via a potentiometer and bang-bang control of their motor; the motor always rotates at full speed (or is stopped). This type of servomotor is not widely used in industrial motion control, but they form the basis of the simple and cheap servos used for radio-controlled models.

SERVO MOTORS vs STEPPER MOTORS

Servo motors are generally used as a high performance alternative to the stepper motor. Stepper motors have some inherent ability to control position, as they have built-in output steps. This often allows them to be used as an open-loop position control, without any feedback encoder, as their drive signal specifies the number of steps of movement to rotate. This lack of feedback though limits their performance, as the stepper motor can only drive a load that is well within its capacity, otherwise missed steps under load may lead to positioning errors.

The encoder and controller of a servo motor are an additional cost, but they optimise the performance of the overall system (for all of speed, power and accuracy) relative to the capacity of the basic motor. With larger systems, where a powerful motor represents an increasing proportion of the system cost, servo motors have the advantage.

SERVO MOTORS vs DC MOTORS

A DC motor has a two wire connection. All drive power is supplied over these two wires—think of a light bulb. When you turn on a DC motor, it just starts spinning round and round. Most DC motors are pretty fast, about 5000 RPM (revolutions per minute).

With the DC motor, its speed (or more accurately, its power level) is controlled using a technique named pulse width modulation, or simply PWM. This is idea of controlling the motor’s power level by strobing the power on and off. The key concept here is duty cycle—the percentage of “on time” versus“off time.” If the power is on only 1/2 of the time, the motor runs with 1/2 the power of its full-on operation.

A servo motor is an entirely different story. The servo motor is actually an assembly of four things: a normal DC motor, a gear reduction unit, a position-sensing device (usually a potentiometer—a volume control knob), and a control circuit.

The function of the servo is to receive a control signal that represents a desired output position of the servo shaft, and apply power to its DC motor until its shaft turns to that position. It uses the position-sensing device to determine the rotational position of the shaft, so it knows which way the motor must turn to move the shaft to the commanded position. The shaft typically does not rotate freely round and round like a DC motor, but rather can only turn 200 degrees or so back and forth.

The servo has a 3 wire connection: power, ground, and control. The power source must be constantly applied; the servo has its own drive electronics that draw current from the power lead to drive the motor.

The control signal is pulse width modulated (PWM), but here the duration of the positive-going pulse determines the position of the servo shaft. For instance, a 1.520 millisecond pulse is the center position for a Futaba S148 servo. A longer pulse makes the servo turn to a clockwise-from-center position, and a shorter pulse makes the servo turn to a counter-clockwise-from-center position.

The servo control pulse is repeated every 20 milliseconds. In essence, every 20 milliseconds you are telling the servo, “go here.”

To recap, there are two important differences between the control pulse of the servo motor versus the DC motor. First, on the servo motor, duty cycle (on-time vs. off-time) has no meaning whatsoever—all that matters is the absolute duration of the positive-going pulse, which corresponds to a commanded output position of the servo shaft. Second, the servo has its own power electronics, so very little power flows over the control signal. All power is draw from its power lead, which must be simply hooked up to a high-current source of 5 volts.

TYPES of SERVO MOTORS

1- Simple Servo : The average servo is the most common type of RC (radio control) servo on the market. They work exactly as expected and typically have a range of motion somewhere between 180º and 360º.

2- Continuous Rotation Servo: These are a subset of servos that do not track position. They have been modified to always report a current position of 0 so when they rotate they keep turning until the target position is set to 0.

3- Linear Actuator Servo: Linear servos behave like pistons, extending and contracting. This is achieved by using a screw thread at the end of the gearbox, changing the rotational motion to linear motion. Other than that, it behaves the same as any other servo motor.

4- Digital Servo: Digital servos behave in the same way as traditional servos except their internals are different. Normally, a servo motor consists of a DC motor, a potentiometer, and a small analog circuit which acts as a controller to keep the motor in position. In the case of digital servos, the analog circuit is replaced with a microprocessor which performs the same function. This allows digital servos to have faster response times, more accurate control of position and velocity, and more torque per size. However, digital servos use substantially more power than their analog counterparts. This means that for the same power supply you will be able to operate fewer digital servos than analog. Depending on the size of the digital servo, you may need an external power supply when using them.

Some digital servos are designed such that the control system retains its previous value when position commands stop coming in from the controller. This has the unusual effect of making the motor hold its position forcibly even when you disengage the motor programmatically. This can often be undesirable since it means the motor is still drawing power and that it will not turn. In order to avoid this behaviour with this type of servo you will need to use a relay or switch of some kind on the red wire going to the motor (the power wire) so that you can completely disengage the motor when you need to.

There are two types of servo Motors by Current - AC and DC. AC servo can handle higher current surges and tend to be used in industrial machinery. DC servos are not designed for high current surges and are usually better suited for smaller applications. Generally speaking, DC motors are less expensive than their AC counterparts. These are also servo motors that have been built specifically for continuous rotation, making it an easy way to get your robot moving. They feature two ball bearings on the output shaft for reduced friction and easy access to the rest-point adjustment potentiometer.

LINEAR SERVO MOTOR VIDEO

This video shows position controlled linear servo motor. The motor is basically a magnet track on aluminum base and a coil unit below car. The feedback comes from linear encoder in front side of this assembly. This demonstrates automatic homing controller of Granite Devices VSD-XE drive. The homing starts automatically when power is switched on and after finding the “hard stop” the car is driven to center position. Repeatability of hard stop homing can be as high as +/- 10µm. After homing is done, some random position moves are commanded to drive. The motor moves at velocity of 2000 mm/s and accelerates at 5G’s.

HOW to SELECT A SERVO MOTOR

Servos have 3 main attributes that must be taken into account when choosing what servo is correct for your application:

1. What range of motion do you need? Servos’ range of motion can be shortened programmatically without issue. But to get a larger range, you will need to get a servo that can reach it out of the box. Servos commonly come with 180º range or more.
2. How accurate do you need the position control to be? The larger a servo’s range of motion is, the less resolution you will have for position accuracy (depending on the quality of the servo).
3. How much torque do you need? Some servos provide more torque than others and depending on your application you might need high torque, or low torque.

Resources

http://handyboard.com/hb/faq/hardware-faqs/dc-vs-servo/
http://www.phidgets.com/docs/Servo_Motor_and_Controller_Primer

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What are STEP MODES ?

Stepper motor “step modes” include Full, Half and Microstep. The type of step mode output of any stepper motor is dependent on the design of the driver. The 4th is a different drive system and rarely used.

Full Step (2 Phases On)
Standard hybrid stepping motors have 200 rotor teeth, or 200 full steps per revolution of the motor shaft. Dividing the 200 steps into the 360° of rotation equals a 1.8° full step angle. Normally, full step mode is achieved by energizing both windings while reversing the current alternately. Essentially one digital pulse from the driver is equivalent to one step.

Half Step (1-2 Phases On)
Half step simply means that the step motor is rotating at 400 steps per revolution. In this mode, one winding is energized and then two windings are energized alternately, causing the rotor to rotate at half the distance, or 0.9°. Although it provides approximately 30% less torque, half-step mode produces a smoother motion than full-step mode.

Micro Step
Microstepping is a relatively new stepper motor technology that controls the current in the motor winding to a degree that further subdivides the number of positions between poles. Some microstepping drives are capable of dividing a full step (1.8°) into 256 microsteps, resulting in 51,200 steps per revolution (.007°/step). Microstepping is typically used in applications that require accurate positioning and smoother motion over a wide range of speeds. Like the half-step mode, microstepping provides approximately 30% less torque than full-step mode.

Wave Drive
In this drive method only a single phase is activated at a time. It has the same number of steps as the full step drive, but the motor will have significantly less than rated torque. It is rarely used.

STEPPER MOTOR DRIVER Technology Overview

The stepper motor driver receives step and direction signals from the indexer or control system and converts them into electrical signals to run the step motor. One pulse is required for every step of the motor shaft. In full step mode, with a standard 200-step motor, 200 step pulses are required to complete one revolution. The speed of rotation is directly proportional to the pulse frequency. Some drivers have an on-board oscillator which allows the use of an external analog signal or joystick to set the motor speed.

Speed and torque performance of the step motor is based on the flow of current from the driver to the motor winding. The factor that inhibits the flow, or limits the time it takes for the current to energize the winding, is known as inductance. The effects of inductance, most types of driver circuits are designed to supply a greater amount of voltage than the motor’s rated voltage. The higher the output voltage from the driver, the higher the level of torque vs. speed. Generally, the driver output voltage (bus voltage) should be rated at 5 to 20 times higher than the motor voltage rating. In order to protect the motor from being damaged, the step motor drive should be current-limited to the step motor current rating.

Vibration Problem

When a step motor makes a move from one step to the next, the rotor doesn’t immediately stop. the rotor actually passes the final position, is drawn back, passes the final in the opposite direction and continues to move back and forth until it finally comes to a rest (see interactive diagram below). We call this “ringing” and it occurs every single step the motor takes. Similar to a bungee cord, the momentum carries the rotor past its stop point, it then “bounces” back and forth until finally coming to rest. In most cases, however, the motor is commanded to move to the next step before it comes to a rest.

The graphs below show the ringing under different load conditions. Unloaded, the motor exhibits a lot of ringing. A lot of ringing means a lot of vibration. The motor will often stall if it is unloaded or lightly loaded because the vibration is so high it will lose synchronism. When testing a step motor always be sure to add a load.

The other two graphs show the motor with a load. Loading a motor properly will smooth out its performance. The load should require between 30% to 70% of the torque the motor can produce, and the ratio of load inertia to rotor inertia should be between 1:1 and 10:1. For shorter, quicker moves, the ratio should be closer to 1:1 to 3:1.

TIPS Before Purchasing a Stepper Motor

The following are unscientific rules of thumb for purchasing the right motor:

-Generally, the longer the motor body, the more torque the motor has.
-If a motor is rated to more amps or volts than your driver can produce, your motor will not produce the manufacturer’s rated torque.
-A motor can safely exceed its rated voltage with a chopping stepper driver (which is all the RepRap stepper drivers, save only the Gen3 electronics extruder board hack). It cannot exceed its rated current (amps) without severely overheating and dying a quick death.
-Stepper motors are generally rated for a 50 °C temperature rise at rated current/torque.
-ABS melts at 105-120 °C but softens at 80 °C. Therefore you probably can’t run your steppers at their full rated torque without melting your plastic motor mounts.
-Power is measured in watts (W) and is calculated as volts (V) × current (A).
-Power made available to a motor will be turned into heat and motion.
-The more power made available to the motor the higher the amount of heat and motion. Heat is proportional to current squared while motion is proportional to current, so losing a little motion (torque) can lose a lot of heat.
-Current and torque are related. The more current, the more torque. More current also means more power requirement and more heat on motor and stepper driver.
-A motor’s rated amps, volts, or ohms (if missing from the spec sheet) can be calculated with the other two numbers using Ohm’s law.

Conclusion

In summary, step motors are excellent for positioning applications. Step motors can be precisely controlled in terms of both distance and speed simply by varying the number of pulses and their frequency. Their high pole count gives them accuracy while at the same time they run open loop. If sized properly for the application, a step motor will never miss a step. And because they don’t need positional feedback, they are very cost effective.

STEPPER MOTOR BASICS – PDF DOCUMENT

TERMS used -Step Motors

NEMA : Refers to the frame size of the motor as standardized by the US National Electrical Manufacturers Association in its Publication ICS 16-2001. It specifies the ‘face’ size of the motor but not its length. For example a NEMA 23 stepper has a face of 2.3 x 2.3 inches with screw holes to match. Note: just because a motor is bigger does not mean it is more powerful in terms of torque. It is perfectly possible for a NEMA 14 to ‘out pull’ a NEMA 17 or a NEMA 23.

Step Angle:  Stepper motors have a step angle. A full 360° circle divided by the step angle gives the number of steps per revolution. For example, 1.8° per full step is a common step size rating, equivalent to 200 steps per revolution. Most stepper motors used for a Mendel have a step angle of 1.8 degrees. It is sometimes possible to use motors with larger step angles, however for printing to be accurate, they will need to be geared down to reduce the angle moved per step, which may lead to a slower maximum speed.

Micro Stepping: A stepper motor always has a fixed number of steps. Microstepping is a way of increasing the number of steps by sending a sine/cosine waveform to the coils inside the stepper motor. In most cases, micro stepping allows stepper motors to run smoother and more accurately.  Microstepping between pole-positions is made with lower torque than with full-stepping, but has much lower tendency for mechanical oscillation around the step-positions and you can drive with much higher frequencies. If your motors are near to mechanical limitations and you have high friction or dynamics, microsteps don’t give you much more accuracy over half-stepping. When your motors are ‘overpowered’ and/or you don’t have much friction, then microstepping can give you much higher accuracy over half-stepping. You can transfer the higher positioning accuracy to moving accuracy too.

Bipolar Stepper Motor:  Bipolar refers to the internals of the motor, and each type has a different stepper driver circuit board to control them. Bipolar motors are the strongest type of stepper motor. You identify them by counting the leads – there should be four or eight. They have two coils inside, and stepping the motor round is achieved by energising the coils and changing the direction of the current within those coils. This requires more complex electronics than a unipolar motor, so we use a special driver chip to take care of all that for us.

Unipolar Stepper Motor:  Unipolar motors also have two coils, but each one has a centre tap. They are readily recognizable because they have 5, 6 or even 8 leads. It is possible to drive 6 or 8 lead unipolar motors as bipolar motors if you ignore the centre tap wires.

Stepper Motor Holding Torque: Stepper motors do not offer as much torque or holding force as comparable DC servo motors or DC gear motors. Their advantage over these motors is one of positional control. Whereas DC motors require a closed loop feedback mechanism, as well as support circuitry to drive them, a stepper motor has positional control by its nature of rotation via fractional increments.

Stepper Motor Size: The physical size of stepper motors are usually described via a US-based NEMA standard, which describes the bolt-up pattern and shaft diameter. In addition to the NEMA size rating, stepper motors also also rated by the depth of the motor in mm. Typically, the power of a motor is proportional to the physical size of the motor. If using the smaller NEMA 14 motors, aim for the high torque option. NEMA 14s are neater, lighter and smaller, but can be hard to obtain with the appropriate holding torque.  NEMA 14s are running near the edge of their envelope: they will get warm.

Stepper Motor Heat: Most of the motors specs give the current for two coils that will give an 80 °C rise, i.e. they can run at 100 °C!  When using them on plastic brackets you need to under-run them to keep the brackets from melting. With PLA’s glass transition temperature between 60-65 °C, you have to seriously under-run them! Fortunately temperature rise is proportional to power, which is in turn proportional to the square of current (P=I2R), but torque is directly proportional so you can keep temperature under control without losing too much torque. For example, running a stepper at 70% of the rated current would result 70% of the torque and 49% (0.72=0.49) of the power dissipation and thermal rise.

Holding Torque : The maximum torque produced by the motor at standstill.

Stepper Motor Pull-out Torque:  is measured by accelerating the motor to the desired speed and then increasing the torque loading until the motor stalls or misses steps. This measurement is taken across a wide range of speeds and the results are used to generate the stepper motor’s dynamic performance curve. As noted below this curve is affected by drive voltage, drive current and current switching techniques. A designer may include a safety factor between the rated torque and the estimated full load torque required for the application.

Resources

http://reprap.org/wiki/Stepper_motor
http://www.omega.com/prodinfo/stepper_motors.html
http://en.wikipedia.org/wiki/Stepper_motor
http://www.orientalmotor.com/technology/articles/step-motor-basics.html

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