Hobbyist electronics projects need robust, reliable power supplies for prototyping and testing. I learned how to build this circuit from the Basic Analog Circuits class at ITP taught by Eric Rosenthal, but took it several steps further in building a solid enclosure and integrating a voltage meter. Now it lives on my desk, ready to power most small projects I’m working on, ranging from 0 – 24 volts and up to two amps. You can learn all about how to make one yourself using this Make: Projects tutorial.
The mini volt meter from Adafruit is what brought this project to the next level. All of the components on this three-digit, seven-segment display are packaged into a small size. All you need to do to integrate it into any project is attach a positive and negative lead to whatever you wish to measure.
Mini Volt Meter. Put a voltage meter anywhere with this very handy display. These are often used by RC hobbyists for keeping track of batteries but we thought it would be great on a breadboard or enclosure.
Simply connect the red wire to the positive supply, and black to negative ground. The display has a microcontroller that will read the voltage, compare it to a stable reference and display the voltage with 0.1V precision on a 3-digit 7-segment display. It works from 3.2V up to 30V so it will be good for nearly any electronic project! The meter draws 3-4mA to power the microcontroller and display. This particular LED display is a nice vivid green, which we found very readable. Mounting tabs make this module easy to attach to any box or plate.
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Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.