Iron Man Arc Reactors have brought joy to makers of all ages, whether as something cool on a movie screen, as a hacked together light assembly, or even a cosplay prop created from a DIY kit. Michael Klements decided to turn one of these kits into something more, by hooking it up to act as a CPU performance monitor for his computer.

His handy desktop device runs a Python script on the monitored PC, which passes along CPU information over serial to an Arduino Uno. The Uno pulses the Arc Reactor in proportion to the computer load using a transistor, with higher frequency pulses indicating a heavily loaded CPU and lower frequencies for lower CPU usage. An OLED display is also implemented for numerical feedback, and everything is housed in a nice 3D-printed stand.

More details, including files and code, are available in Klements’ blog post.