I built this project to handle common control, measurement and automation tasks that I run into on a regular basis. I tried to make the design as modular and flexible as possible so it can be configured to support a number of projects. This is my third major revision of this project and the first I feel good enough about to share.
The board can control both DC and AC supplies. On the DC side, I designed the board to handle up to 40V and 6A and the supply and load can be controlled independently. The DC load can be either resistive or inductive. The Arduino controls all the elements on the board and can measure both directly with its analog inputs as well as using the Adafruit High-Side voltage and current sensor. I added the AC control with a solid state relay for completeness though I admit I am not sure how I will use it.
Here is one scenario I am using this board for - battery run-down testing for an IOT device. The steps include:
- Hook up battery to the Source connector
- Connect my IOT devices' power supply to the test connectors
- Add a "worst case" load to the load connector
- Tape a TMP-36 temperature probe to the converter chip and the analog header
- Program a load profile using PWM into the Arduino (Transmitting, Awake, Asleep)
- Execute the test with the Arduino logging voltages, currents and temperatures
- Importantly, the Arduino can end the test based on set performance / safety rules
I could imagine some other cool uses including:
- Connecting a WiFi or Bluetooth module enabling remote control
- Turning on an off an AC power supply once the test is complete
- Using the Load FET to control AC or DC motors
- Can be used with 3.3V logic devices, simply replace 5V Pro Mini with 3.3V
- Automated testing of new power supplies to make sure they meet deign specs
You can use the EAGLE files I have uploaded to customize the board or you can order it from OSHPark.