Planet Arduino

As seen here, Juan had some problems with his power supply, and while he wanted to “simply” build another one, he didn’t let the power supply go to waste. Instead he converted it into an adjustable dummy load based on the design by Dave Jones’ shown below.

This device, however, is no mere duplication of Jones’ and adds an Arduino for control, allowing for voltage, current, power, and temperature monitoring. The enclosure was designed in Fusion 360 and 3D-printed, and the front panel overlay in Inkscape. 

Other interesting tricks include using a readily available DC motor for input instead of an encoder, along with an array of 7-segment displays that don’t quite all match, but act as functional outputs nonetheless. 

Code for the project is up on GitHub.

If you need a device which draws a certain amount of current and power for testing, then GreatScott! has just the solution. 

His project uses an Arduino Nano, along with a separate IC and a voltage divider, to measure both current and voltage input from the power source. It then employs this data to properly adjust a MOSFET, dissipating the correct amount of voltage and power as required.

Interface is handled via a rotary encoder and a 16×2 I2C LCD display, and the electronics are housed in a solid-looking enclosure. 

As seen in the video below, the adjustable constant load features an impressively large heat sink, needed to take care of the 30V and 20A that the setup is capable of drawing.