This idea was inspired by Russell Durrett's Light Bulb PCR Machine. http://russelldurrett.com/lightbulbpcr.html
I decided to attempt to make a similar device with parts I already had on hand. I replaced the light bulb with a 3D printing heating element from an old 3D printer. The 40mm fan came from the printer as well. The UNO, temperature sensor and relay came from an Arduino starter kit I had. I did have to buy the 12VDC/5 Amp power supply since the 12VDC/3Amp one I had was insufficient.