Just finished my fermentation chamber! Total cost was about $240. I'll be adding an LCD to the Arduino, and when I build the second chamber, I'll add an LCD to the Raspberry Pi, so I don't have to use the monitor with it. I had some spare Cat6 cable that I used for the temperature sensors/circulation fan and some spare 4pin phone cable for the Arduino to 2 Channel Relay. I want to start building the second one now, but I should probably brew first...
Below is the cost breakdown:
IGLOO 4.6 Cu Ft - FR464 : $109.95
Arduino Uno : $12.60
Raspberry Pi : $37.88
120mm Silent Fan : $14.88
Arduino Mount : $5.50
Heat Tape : $19.98
Temperature Sensors : $3.60
Thermowell : 15.85
Outlet & Cover : $4.99
Outlet Box : $8.20
2CH Relay : $3.59
Resistor : $0.10