Open-Source Microcontrollers for Science - Open-Source Lab: How to Build Your Own Hardware and Reduce Research Costs - page 73

style RepRap like the 3-D printer described in the next chapter. Next, drill a hole from outside
to the inside of your chamber to run the following wires: power resistors, fan, and thermistors.
This “data and power” hole should be near the top of the chamber. Next, use a sturdy sheet
(we used plywood, but this will depend on your application), cut to size to split the cooler in
two sections—the upper section contains most of the parts and also is the work area; the bot-
tom section will be used to place the dehumidifier(s). The base sheet must be thick enough to
mechanically support whatever you want to put in your environmental chamber. It must have
a square hole cut in it for the fan and some small holes for air circulation. This can be done
most easily with an electrical drill and a jigsaw—but can be accomplished by hand tools for
whatever you have available (e.g. laser cutter, water jet cutter, etc.). Next, fix the metal sheets
on the cooler sides together with the power resistors as seen in Figures 4.15 and 4.16 .
FIGURE 4.15 Inside of the Bear Chamber showing placement of components.