It’s a story about the evolving relationship between humans and robots, and what AI in machines bodes for the future of war and the human race.

Resources

Read Now: The Evil ‘Star Wars’ Robot Who Owns the Term ‘Meatbag’ – http://bit.ly/1Hy6KLU
Subscribe to MOTHERBOARD: http://bit.ly/Subscribe-To-MOTHERBOARD

The post The Dawn of KILLER ROBOTS appeared first on Robotpark ACADEMY.

For speech recognition, specialties include vowel sounds, consonant sounds, grammar, syntax, context, and other variables. For example, a context specialty program might determine whether a speaker means to say “weigh” or “way,” or “two,” “too,” or “to.” Another program lets the controller know when a sentence is finished and the next sentence is to begin. Another program can tell the difference between a statement and a question. Using the blackboard as their forum, the specialty circuits “debate” the most likely and logical interpretations of what is heard or seen. A “referee” called a focus specialist mediates.

For object recognition, specialties might be shape, color, size, texture, height,width, depth, and other visual cues.How does a computer know if an object is a cup on a table, or a water tower a mile away? Is that a bright lamp, or is it the sun? Is that biped thing a robot, a mannequin, or a person? As with speech recognition, the blackboard serves as a debating ground.

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The common principle of all screws is that a rotating helix can cause linear motion.

A screw is a mechanism that converts rotational motion to linear motion, and a torque (rotational force) to a linear force. It is one of the six classical simple machines. The most common form consists of a cylindrical shaft with helical grooves or ridges called threads around the outside. The screw passes through a hole in another object or medium, with threads on the inside of the hole that mesh with the screw’s threads. When the shaft of the screw is rotated relative to the stationary threads, the screw moves along its axis relative to the medium surrounding it; for example rotating a wood screw forces it into wood.

In screw mechanisms, either the screw shaft can rotate through a threaded hole in a stationary object, or a threaded collar such as a nut can rotate around a stationary screw shaft. Geometrically, a screw can be viewed as a narrow inclined plane wrapped around a cylinder.

Other mechanisms that use the same principle, also called screws, don’t necessarily have a shaft or threads. For example, a corkscrew is a helix-shaped rod with a sharp point, and an Archimedes’ screw is a water pump that uses a rotating helical chamber to move water uphill. The common principle of all screws is that a rotating helix can cause linear motion.

A screw can amplify force; a small rotational force (torque) on the shaft can exert a large axial force on a load. The smaller the pitch, the distance between the screw’s threads, the greater the mechanical advantage, the ratio of output to input force. Screws are widely used in threaded fasteners to hold objects together, and in devices such as screw tops for containers, vises, screw jacks and screw presses.

 Screw Type – JACK

Mechanisms are often required to move a large load with a small effort. For example, a car jack allows an ordinary human to lift a car which may weigh as much as 6000 lb, while the person only exerts a force equivalent to 20 or 30 lb.

The screw jack, shown in Fig. is a practical application of the inclined plane because a screw is considered to be an inclined plane wrapped around cylinder. A force F must be exerted at the end of a length of horizontal bar l to turn the screw to raise the load (weight W) of 1000 lb. The 5-ft bar must be moved through a complete turn or a circle of length s  2 l to advance the load a distance h of 1.0 in. or 0.08 ft equal to the pitch p of the screw. The pitch of the screw is the distance advanced in a complete turn.

Advantages

An advantage of jackscrews over some other types of jack is that they are self-locking, which means when the rotational force on the screw is removed, it will remain motionless where it was left and will not rotate backwards, regardless of how much load it is supporting. This makes them inherently safer than hydraulic jacks, for example, which will move backwards under load if the force on the hydraulic actuator is accidentally released.

Mechanical Advantage

The mechanical advantage of a screw jack, the ratio of the force the jack exerts on the load to the input force on the lever, ignoring friction, is

where ;

  is the force the jack exerts on the load

 i s the rotational force exerted on the handle of the jack

  is the length of the jack handle, from the screw axis to where the force is applied

  is the lead of the screw.

However, most screw jacks have large amounts of friction which increase the input force necessary, so the actual mechanical advantage is often only 30% to 50% of this figure.

Torque Form

The rotational force applied to the screw is actually a torque . Because of this, the input force required to turn a screw depends on how far from the shaft it is applied; the farther from the shaft, the less force is needed to turn it. The force on a screw is not usually applied at the rim as assumed above. It is often applied by some form of lever; for example a bolt is turned by a wrench. The mechanical advantage in this case can be calculated by using the length of the lever arm for r in the above equation. This extraneous factor r can be removed from the above equation by writing it in terms of torque:

Actual Mechanical Advantage and Efficiency

Because of the large area of sliding contact between the moving and stationary threads, screws typically have large frictional energy losses. Even well-lubricated jack screws have efficiencies of only 15% – 20%, the rest of the work applied in turning them is lost to friction. When friction is included, the mechanical advantage is no longer equal to the distance ratio but also depends on the screw’s efficiency. From conservation of energy, the work W_in done on the screw by the input force turning it is equal to the sum of the work done moving the load W_out, and the work dissipated as heat by friction W_fric in the screw

The efficiency η is a dimensionless number between 0 and 1 defined as the ratio of output work to input work

Work is defined as the force multiplied by the distance moved, so  and  and therefore

 or in terms of torque  :

So the mechanical advantage of an actual screw is reduced from what it would be in an ideal, frictionless screw by the efficiency . Because of their low efficiency, in powered machinery screws are not often used as linkages to transfer large amounts of power (except in lead screws) but are more often used in positioners that operate intermittently.

Videos – Types of Screw Mechanisms In Action

Ball Screw Mechanism

Youtube Link: http://youtu.be/tTeZmACs93E

Screw Jack Mechanism

Youtube Link:http://youtu.be/fwnQnuDHR7U

The post Robotic MECHANISMS – SCREW SYSTEMS 51007 appeared first on Robotpark ACADEMY.

Hero of Alexandria identified the pulley as one of six simple machines used to lift weights. Pulleys are assembled to form a block and tackle in order to provide mechanical advantage to apply large forces. Pulleys are also assembled as part ofbelt and chain drives in order to transmit power from one rotating shaft to another.

Example of a Pulley System

In the typical pulley system, shown in Fig. 3a, each block contains two pulleys or sheaves within a frame or shell. The upper block is fixed and the lower block is attached to the load and moves with it. A cable fastened at the end of the upper block passes around four pulleys before being returned to the operator or other power source.

Figure b shows the pulleys separated for clarity. To raise the load through a height h, each of the sections of the cable A, B, C, and D must be moved to a distance equal to h.

The operator or other power source must exert a force F through a distance s = 4h so that the velocity ratio of s to h is 4.

Therefore, the theoretical mechanical advantage of the system shown is 4, corresponding to the four cables supporting the load W. The theoretical mechanical advantage TA for any pulley system similar to that shown equals the number of parallel cables that support the load.

Learning Videos

Links

-Youtube Video Link: http://youtu.be/LiBcur1aqcg
-Youtube Video Link: http://youtu.be/i2bGTC27OJU
-Youtube Video Link : http://youtu.be/3YLc9_-ZXT0

The post Robotic MECHANISMS – PULLEY SYSTEMS 51005 appeared first on Robotpark ACADEMY.

Simple machines are evaluated on the basis of efficiency and mechanical advantage. While it is possible to obtain a larger force from a machine than the force exerted upon it, this refers only to force and not energy; according to the law of conservation of energy, “more work cannot be obtained from a machine than the energy supplied to it”.

Because Work = Force * Distance, for a machine to exert a larger force than its initiating force or operator, that larger force must be exerted through a correspondingly shorter distance. As a result of friction in all moving machinery, the energy produced by a machine is less than that applied to it. Consequently, by interpreting the law of conservation of energy, it follows that:

Input Energy = output energy + wasted energy

This statement is true over any period of time, so it applies to any unit of time; because power is work or energy per  unit of time, the following statement is also true:

Input Power = output power + wasted power

The efficiency of a machine is the ratio of its output to its input, if both input and output are expressed in the same units of energy or power. This ratio is always less than unity, and it is usually expressed in percent by multiplying the ratio by 100.

Percent Efficiency = (output energy / input energy) * 100

Percent Efficiency =  (output power / input power) * 100

A machine has high efficiency if most of the power supplied to it is passed on to its load and only a fraction of the power is wasted. The efficiency can be as high as 98 percent for a large electrical generator, but it is likely to be less than 50 percent for a screw jack. For example, if the input power supplied to a 20-hp motor with an efficiency of 70 percent is to be calculated, the foregoing equation is transposed.

Input power = (output power / percent efficiency) * 100

 = 20 hp / 70 * 100 = 28,6 hp

(Attention: There are lots of “Free Energy” or “Perpetual Motion” Videos on the web. But Perpetual Motion is possible. Because they are all against the Law of Conservation of Energy ) - Perpetual motion describes “motion that continues indefinitely without any external source of energy; impossible in practice because of friction (Wasted Energy)

MECHANICAL ADVANTAGE

What is Mechanical Advantage ?

Mechanical advantage is a measure of the force amplification achieved by using a tool, mechanical device or machine system. Ideally, the device preserves the input power and simply trades off forces against movement to obtain a desired amplification in the output force. Machine components designed to manage forces and movement in this way are called mechanisms.

An ideal mechanism transmits power without adding to or subtracting from it. This means the ideal mechanism
-does not include a power source,
– is frictionless,
-constructed from rigid bodies that do not deflect or wear.

The performance of real systems is obtained from this ideal by using efficiency factors that take into account friction, deformation and wear.

The mechanical advantage of a mechanism or system is the ratio of the load or weight W, typically in pounds or kilograms, divided by the effort or force F exerted by the initiating entity or operator, also in pounds or kilograms. If friction has been considered or is known from actual testing, the mechanical advantage,

MA, of a machine is:

MA = load / effort = W / F

Ideal Mechanical Advantage

The ideal mechanical advantage (IMA), or theoretical mechanical advantage, is the mechanical advantage of a device with the assumption that its components do not flex, there is no friction and no wear. It is calculated using the physical dimensions of the define and defines the maximum performance the device can achieve.

The assumptions of an ideal machine are equivalent to the requirement that the machine does not store or dissipate energy, thus the power into the machine equals the power out. Therefore, the power P is constant through the machine and force times velocity into the machine equals the force times velocity out, that is

The ideal mechanical advantage is the ratio of the force, or effort, out of the machine relative to the force or effort into the machine, that is

The constant power relationship provides yields a formula for this ideal mechanical advantage in terms of the speed ratio,

The speed ratio of a machine can be calculated from its physical dimensions, thus the assumption of constant power allows the use of speed ratio to determine the maximum value for the mechanical advantage.

Actual Mechanical Advantage

The actual mechanical advantage (AMA) is the mechanical advantage determined by physical measurement of the input and output forces. Actual mechanical advantage takes into account energy loss due to deflection, friction, and wear.

The AMA of a machine is calculated as the ratio of the measured force output to the measured force input,

where the input and output forces are determined experimentally.

The ratio of the experimentally determined mechanical advantage to the ideal mechanical advantage is the efficiency η of the machine,

Links

Youtube Video: http://youtu.be/wyNEJyiqcNw

The post Efficiency of Machines & Mechanical Advantage 51006 appeared first on Robotpark ACADEMY.

Complex machines from internal combustion engines to helicopters and machine tools contain many mechanisms. However, it might not be as obvious that mechanisms can be found in consumer goods from toys and cameras to computer drives and printers.

In fact, many common hand tools such as scissors, screwdrivers, wrenches, jacks, and hammers are actually true mechanisms. Moreover, the hands and feet, arms, legs, and jaws of humans qualify as functioning mechanisms as do the paws and legs, flippers, wings, and tails of animals.

There is a difference between a machine and a mechanism: All machines transform energy to do work, but only some mechanisms are capable of performing work. The term machinery means an assembly that includes both machines and mechanisms.

Fig. 1:  Cross section of a cylinder of an internal combustion engine showing piston reciprocation (a), and the skeleton outline of the linkage mechanism that moves the piston (b).

Figure 1a illustrates a cross section of a machine—an internal combustion engine. The assembly of the piston, connecting rod, and crankshaft is a mechanism, termed a slider-crank mechanism. The basic schematic drawing of that mechanism, Fig. 1b, called a skeleton outline, shows only its fundamental structure without the technical details explaining how it is constructed.

Basics of Robotics Mechanisms

-Inclined Plane
-Pulley Systems
-Screw Systems
-Levers
-Linkages – Simple Planar Linkages

-Physical Principles – Efficiency of Machines & Mechanical Advantage

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“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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“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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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

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