DIY Automatic Temperature-Controlled Disinfection Machine

If you are interested in building a DIY automatic temperature-controlled disinfection machine, you may want to take a look at this article.

If you happen to have a temperature controller and a 1600-watt hair dryer, you can use these two components to build a simple automatic temperature-controlled disinfection machine.

This temperature controller operates at 12V, but its built-in relay is rated for only 120 watts, which is not enough to power a 1600-watt hair dryer. Fortunately, if you have a 5V relay available, you can modify the power supply of the temperature controller by removing the 5V LDO and switching to direct power supply. You can also remove the original built-in relay and connect two external 5V double-pole, 5A relays using jumper wires. When the two relays are connected in parallel, they can handle up to 10A of current and support a 2200-watt load, leaving sufficient power headroom.

You can then use a 220V-to-5V power supply board to provide power to the temperature controller and relays.
With a 220V input, the temperature controller controls the relays, and the relays then control the on/off switching of one of the 220V power lines. This setup forms a complete temperature control system, as shown below.

If you do not have an insulated box for the time being, you can first use a small cardboard box and place the hair dryer inside it. Place the temperature sensor probe at the other end of the cardboard box. Set the starting temperature below 60°C so that the relays turn on and the hair dryer receives power to generate heat. When the temperature rises above 65°C, the relays turn off, cutting power to the hair dryer. After testing, you can maintain the temperature inside the cardboard box within the range of 60°C to 65°C. The project is complete.