The Snout-Like "PiggyMeter" Is a Home Assistant-Compatible Sensor for Energy Meters and More

Pseudonymous maker "Aquaticus" has designed a kit to get your energy, water, or other IEC 62056-21-compatible meter talking to Home Assistant or other smart home platforms, dubbed the PiggyMeter — thanks to its snout-like appearance.

"[The PiggyMeter can] read data from an electric meter or any device with a compatible interface," Aquaticus explains of his creation, which communicates with the meter over an IEC 62056-21 connection. "It uses widely available components, open source software, and is compatible with [the] popular home automation software Home Assistant."

The reason for the device's unusual name is the result of its 3D-printed three-part plastic housing, which when assembled looks uncannily like the snout of a pig. It's no comedy design, though: the "snout" is built to mate with the optical interface on compatible meters, providing an isolated connection from which it can safely draw readings.

Inside that snout-like housing is a Lolin Wemos S2 or C2 Mini board, based on the Espressif ESP32-S2 and ESP32-S3 respectively, with 2MB of pseudo-static RAM (PSRAM) and 4MB of flash storage, which runs the ESPHome firmware and its IEC 62056-21 component — providing compatibility with modes A, B, C, and D, but not mode E, and only for meters which provide readings as ASCII-encoded data.

Assuming your meter meets the requirements, the snout connects using a simple magnet which places the custom-built optical interface where it can begin to take readings. There's no battery, but the microcontroller can be powered via its USB Type-C port — and sends its readings to Home Assistant or other compatible smart home platform over Wi-Fi.

Full details on building your own PiggyMeter are available on Acquaticus' website; the maker is also selling a kit with all the required components, bar the meter to be read, on Tindie at $39.99 or $14.99 for just the optical interface board.