Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

Sorry it took so long to respond to your msg JB, but been pretty busy last couple of days.

The temperature controller is not published - wasn't sure if anyone had much interest. It's pretty simple and not sophisticated at all. I have looked at using a PID, but am currently at a simpler approach. I have the program set to heat on HIGH until 20ºF before setpoint, then the PWM output starts slowing in a steady 255 steps until at setpoint the output is zero. As the temperature falls 1ºF below setpoint the PWM starts slowly ramping up to keep temp from heating too much.

This provides a ±3ºF spread - maybe 4ºF but works pretty good.

I like the idea of epoxy for the walls - I have a couple of PCBs that are almost 1/4" that would work a treat for that. I could use the old plastic (before melting:) as a pattern, and a scroll saw to cut the pattern.

Good luck and having fun!!

Ken H>