In a laboratory setting, precision is essential. When heating up liquids, being even a degree off could spell ruin for an experiment. Therefore, Maker BrittLiv developed a DIY programmable heating pad that can run intricate temperature ramps – for only $100!
As a chemical and biological engineering student, BrittLiv was priced out of the market for most laboratory quality heating devices; though, when making her own she did not want to sacrifice quality or functionality. “When you try to develop catalysts for chemical processes, the temperature program and exact temperature control is crucial. You probably do not want to stay in the lab for 16 hours to manually adapt your temperature,” she notes.
With a hot plate and a series of electronic components including a LCD screen, a few solid-state relays, and an Atmel ATmega328 gathered, BrittLiv was ready to assemble her contraption. She began by linking the hot plate and the input device. “It is very advisable to use a ground fault circuit interrupter adapter or a safety socket when working on and with the device,” the Maker advises. The embedded AVR microcontroller monitors the heating process, with temperatures up to 338°F, via an MAX6675 thermocouple interface board.
From there, she programmed her electronics to read temperature scales from an SD card. BrittLiv stressed the importance of scales by saying, “It is not enough to simply hold something at a certain temperature, but the rate at which something is heated and for how long is just as important.”
Once her entire unit was soldered and linked, she placed a heat safe wooden case around the input device and sprayed it with heat-resistant paint.
For a full tutorial on how to build your own programmable heating pad, check out BrittLiv’s original Instructables post here.