Insulating the cooling chamberSeptember 21, 2004
I insulated the cooling chamber with 2-part polyurethane closed-cell foam. This stuff is great - you mix it up and it gently expands to many times its original volume. It will keep all the cold from "leaking away" into the environment... most importantly, it insulates between the bottom of the heatsink and the back of the cooling chamber!
On the picture of the rear, you can just see a power MOSFET with a green alligator clip attached. This is connected (via the alligator clip) to the PWM output from the microcontroller, and is used to modulate current flow through the peltier device.