You can put a volt meter anywhere using the Mini 3-Wire Volt Meter. This type of mini volt meter is generally used in RC projects to keep track of batteries, but it seems to work perfectly on a breadboard or enclosure. This volt meter has just three wires. Two wires are used to power it and the third wire is used for measurement.
To make measurements with Mini 3-Wire Volt Meter, you just need to
The microcontroller on the mini volt meter reads the voltage and compares it with a stable reference and shows it with a 0.1V precision on a 3-digit 7-segment display. The measurement range of the volt meter is between 0V and 99,99V so it is suitable for all electronics projects. Mini 3-Wire Volt Meter draws only 3-4 mA to power the microcontroller and the display. Mini Volt Meter has mounting tabs which make it easy to attach to any box or plate.
Adafruit Product Page: https://www.adafruit.com/products/705