As a long haul truck driver I use a thermoelectric cooler as opposed to an ice chest. The main problem is that it tends to freeze items placed nearest the cooling element. By placing a couple of 500ml water bottles next to the cooling element I can make ice.
So, I've decided I'll build a freeze protector circuit. I've purchased a relay board, Digispark clone board, DS18B20, and a Arduino Nano clone.
I intended on using the Digispark clone as a the controller but, never could get any of my Debian computer's to recognize it. So, I used the Nano, which was overkill in size, DIO Pins, and processor power.
Sad story, while connecting everything to the cooler, i some how managed to brick the Nano clone. Currently, back to square one until I order a new Nano clone. I'm going to make another attempt at using a different Digispark clone.
Eventually, I'd like to custom build my own PCB with relay and ATtiny85.