Microcontroller Temperature Controlled Pipe Heating keeps Pipe from Freezing

If you live in a cold climate freezing pipes is a common concern. A frozen pipe is more than an inconvenience since most pipes are copper and the expanding ice can easily burst the pipe. So even after the pipe is thawed out you have a big job ahead since you now need to repair your plumbing. Viktor from Karosium has come up with a cost effective solution to dealing with the issue. His Microcontroller Temperature Controlled Pipe Heating System turns on an old computer power supply which powers some heat tape only when the pipe needs to be warmed up. Most people who run heat tape will turn it on when it gets cold and let it run all winter, this solution will certainly save lots of electricity.

“I designed a controller from what I had on hand. An old ATX PSU and an ATMega8(overkill). The AtMega is powered by the standby voltage of the PSU (5VSB). PSON is connected to PORTB.0 so the AtMega can switch the ATX PSU ON or OFF depending on temperature. (The PSU turns on when PSON is pulled low). The heating cables are hooked up to a 4pin Molex Connector. The DS1621 was actually a thermostat IC and I was considering using it in a standalone configuration but sadly that can’t be done as the thermostat functionality doesn’t start until a “Start Convert” command is sent to the chip through I2c. That meant a microcontroller was mandatory, so instead of relying on the internal functionality of the chip I just implemented the thermostat function in code. This also meant I only had to run 4 wires from the temp probe instead of 5, and I had 4 wire telephone cable lying around.”