Localized Heater/Cooler for Agar Plates: Peltier temperature control

For our experiments we needed to heat or cool specific areas on agar plates, so we designed a system that uses Peltier devices as both heating and cooling sources.

I built an Arduino circuit that switches the Peltier devices between modes and holds them at a set temperature, and a Python desktop app to manage the temperature regulation.

Later I designed a dedicated board for it in Altium Designer: a 300 × 200 mm PCB with four Peltier positions around a central plate area, with the connections for each one routed to a single header for the controller.