This tutorial will show you how to make a thermal cycler from scratch for about $85. In short, PCR(polymerase chain reaction) amplifies bits of DNA, creating millions of copies of a target sequence. You can use it to test a DNA sample for a specific gene, for instance, to check for genetic modification in food and for hereditary gene testing.
During PCR, a mixture of DNA, primer and DNA polymerase is cycled between three different temperature settings, over and over again. This project uses an arduino to control two high-power resistors to heat up the sample, a computer fan to cool down, and a thermocouple to keep track of the temperature. The design supports two samples at a time, though it could probably be extended to support more.
The parts are all off-the shelf, and the assembly should take a few hours. You will need access to a shop (at the very least a ban saw and drill press).
Make a robot friend with Adafruit’s CRICKIT – A Creative Robotics & Interactive Construction Kit. It’s an add-on to our popular Circuit Playground Express, FEATHER and other platforms to make and program robots with CircuitPython, MakeCode, and Arduino. Start controlling motors, servos, solenoids. You also get signal pins, capacitive touch sensors, a NeoPixel driver and amplified speaker output. It complements & extends your boards so you can still use all the goodies on the microcontroller, now you have a robotics playground as well.