I've completed the build of my SPEC unit.

1) Added terminal block for external temperature sensor

2) Added 18B20 temperature probe

3) Added power switch

4) Added power indicator LED

5) Adapted Solar Cell wiring to micro USB for 8266 Thing power input (spliced the end of a micro USB charging cable)

6) Added cover gasket (temporarily using rope caulk until I can cut a neoprene gasket)

 

Solar SPEC wiring

Solar SPEC assembly completed

Power switch

 

I still need to update the program to use the 18B20 temperature sensor rather than the DHT22.  And I need to change the offset in the irradiance reading.  I'm not sure what I will do for a finale video as this thing doesn't have any moving parts.