Chad Kapper's Outlet Checkers Tap Into Espressif's ESP-NOW for Peer-to-Peer Circuit Breaker Tracking

Five transmitters build a peer-to-peer network with a single receiver — and trigger an alert when the power is cut.

Maker Chad Kapper has designed a smart device family that makes it easier to figure out which circuit breaker is connected to which outlet — by creating a peer-to-peer network of plug-in Wemos Lolin D1 Mini boards.

"This project involves a system of D1 Mini microcontrollers configured for peer-to-peer communication using their built-in Wi-Fi capabilities," Kapper explains of the build. "The primary function of this system is to identify which circuit breakers control specific outlets."

These outlet testers make a peer-to-peer network to help you tie outlets to their circuit breakers. (📷: HackMakeMod)

The circuit-testing system is split into two parts: receiver and transmitter. The transmitters, five in total in Kapper's build, each have their own Wemos Lolin D1 Mini board in a 3D-printed housing designed to neatly slot onto the back of an off-the-shelf USB charging plug. The receiver has a final D1 Mini board, along with five LEDs — each corresponding to one of the five numbered transmitters.

"The [testing] process involves plugging the transmitters into outlets," Kapper explains, "and toggling circuit breakers to observe which LED extinguishes, indicating the associated breaker for each outlet." This is achieved over a peer-to-peer Wi-Fi network driven by Espressif's ESP-NOW, activated and configured via Arduino sketches running on the boards' ESP8266 chips.

The full project write-up, including 3D print files and source code for the transmitters and receiver, is available on Kapper's HackMakeMod site.

Gareth Halfacree
Freelance journalist, technical author, hacker, tinkerer, erstwhile sysadmin. For hire:
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