Detailed Pictures here: youyue858d
This was a $40 Chinese hot air unit that I replaced the microcontroller on with a custom firmware with much tighter controls. The temperature fluctuated +-15C before the mod. Now it holds the temp within about 3C of the setpoint.
Here is me learning that the arduino environment kinda sucks when it comes to more advanced projects. That’s ok, I got to spend a few hours learning a bit more about microcontrollers. I’m using the Bus Pirate along with AVRDude to program my chip and set fusebits.
The custom firmware works wonderfully, but I feel there are some thermal concerns that need to be addressed. I plan to add ventilation and heatsinks as necessary.