The MotherboardSeptember 21, 2004
I moved the motherboard electronics off of the protoboard and actually soldered it together on a breadboard. Here's a closeup shot of the new motherboard - it takes up far less space and is far neater than the prototype.
All the wires to the peripherals have been replaced with ribbon cable. The large connector at the bottom goes to the LCD, the two 3-conductor cables at the top go to the temperature sensors. The 6-conductor cable on the right goes to the optical encoder (with integrated pushbutton switch!).
This knob is also a new addition, replacing the digital switches I was using on the protoboard. Turning the knob adjusts the setpoint, while pressing it changes the display on the LCD. My plan is to have a variety of different displays available.
The two trim pots near the top are used to calibrate the hot and cold temperature sensors. The one on the left controls the LCD contrast, and the one on the right is a current limiter for the LCD's integrated LED backlight.