chronoconstant/sourdough-monitor

Sourdough Monitor is a small battery-powered gadget that sits on the lid of a sourdough starter jar and watches the starter rise after each feeding. The author wanted to know, from a phone or a wall-mounted dashboard, how far the starter has risen and when it peaked, so the next stage of baking can start at the right moment. The whole thing reports into Home Assistant, the open-source smart-home hub. The sensing is done with two parts. A VL53L4CD time-of-flight sensor points straight down into the jar and measures the distance to the top of the starter, which the firmware turns into a height and a rise percent. An SHT31-D sensor reports temperature and humidity, because fermentation speed depends on the kitchen climate. A push button labeled Just Fed lets the baker mark the start of a new cycle: the firmware archives the previous cycle's stats, drops the baseline, and waits for the starter to settle before locking in a new low point against which rise is measured. The brains are a Seeed XIAO ESP32-C3 microcontroller running ESPHome, an open firmware that exposes sensors as Home Assistant entities over MQTT. The board wakes about every 15 minutes, takes a reading, publishes the data, then drops back into deep sleep. The README says a 1200 mAh single-cell LiPo gets roughly a month per charge, and the XIAO charges over its built-in USB-C port. An optional pair of 100 k ohm resistors form a battery voltage divider so the hub can show a battery percentage. The repository ships ESPHome YAML firmware, a separate scanner config for first-time I2C bring-up, a bundled third-party VL53L1X driver, 3D-printable lid enclosure files, a wiring guide, a troubleshooting guide, and a Home Assistant dashboard card plus a past-peak binary sensor that can trigger a phone notification when the starter starts collapsing. The enclosure is sized for a Brod and Taylor jar. The author writes openly that Claude, Anthropic's AI assistant, did most of the firmware and documentation work. The project is licensed under GPLv3, with the bundled VL53L1X driver kept under its original MIT license.