The handy project is built around a small Microchip 12F509 controller, an alarm, and a temperature sensor to remember the monitored temperature of how long it has been above a temperature set point.

Although ultra-low temperature (ULT) freezers are specifically designed to work between -86°C and -45°C, they often work at a set temperature of -70°C or -80°C. These freezers can last for about 12 to ...