ESPHome Wood Stove Temperature Monitor
Jay’s thermocouple setup monitors stove temperature via ESPHome and Home Assistant.
'Tis the holiday season, which coincides with the season where it gets significantly colder in the Northern Hemisphere. While this largely means allowing our air conditioning unit to take a break at my location in sunny Florida, in more northerly climates I’m told that people actually burn wood inside their houses to keep warm.
Jay, as one such person, decided that adding logs to the fire in a somewhat chaotic manner wasn’t good enough, and that he needed a more advanced way to monitor the stove’s status. A simple thermometer on the stove would work, but that would result in a significant lag between when the fire reaches a certain temperature and when the stove itself heats up in response. Instead, he installed a thermocouple in the chimney flue, which produces a near-instantaneous reading of the fire temperature.
Elements used here include a K-type thermocouple, along with a MAX6675 amplifier. This passes data via SPI to an ESP8266 Wemos D1 Mini board running ESPHome firmware. The D1 Mini then transmits temperature data over Wi-Fi to a Home Assistant installation, allowing Jay to view and graph temperature data. Notifications are set up to indicate when more wood is needed in the fire, and when it reaches an "overfire" condition at 800ºF or higher.
Jay’s eventual plan is to automate the stove's air controls, allowing him to simply add more wood as needed. He’d also like to add a sensor toward the top of the chimney, but that will need to wait until it’s not so icy on the roof. While the project still has a few more steps to be “done,” this setup still gives Jay lots of data to minimize both wood use and creosote buildup in the chimney flue.
