Home

Welcome to the OctoPrint-FanSpeedMirror wiki!

This plugin was created because the cooling fans on my printer were not providing enough cooling when printing with PLA. It was suggested that I add a desktop fan which solved the cooling problem but introduced another problem, I had to remember to turn off the external fan for the first layer or I had too much cooling and then I had to remember to turn on the external fan before the print reached the point where additional cooling was required.

There was already a cooling fan on the printer that had these properties, the one controlled by the GCode commands M106 and M107. I didn't want to dive into the internals of the printer to find wires that had the voltage being used to drive that fan and it was a 24v fan which isn't that easy to find. Easy to find, however, are 12V DC fans of all sizes and shapes. Additionally, I already had a Raspberry Pi running OctoPrint and there are numerous ways to get PWM output from the Pi. I purchased an Adafruit DC & Stepper Motor Hat and connected a couple of 80mm 12V DC fans to the frame of my printer. I did dive into the internals to add a 24v to 12v DC to DC converter so the power for the fans was controlled by the power switch on the printer.

What was needed next was a way to intercept the M106 S parameter and the M107 (which in some implementations is replaced by M106 S0). The OctoPrint plugin system provided everything needed and this plugin was born.