>>13385829I doubt you can easily DIY temperature control within 0.01K. But I'd try with something simple at first.
A well thermally insulated chamber (a bucket lined with foam maybe) cooled with a Peltier module with a thermocouple attached to the cool side with thermal paste or something. Put the hot side of the module in a water bath to keep it cool and control the voltage across the module with some microcontroller based on the thermocouple reading. With simple parts and materials, I don't think you can really go much better than that.
An upgrade to that could be filling the chamber with alcohol or something to increase the thermal mass so it's much easier to keep the temperature constant. It would also help make the temperature in the chamber homogeneous.
What is it for?
