ESP32-H2 Turns Old Wired Doorbell Into a Smart Zigbee Device Without Wi-Fi

Maker Philipp Schweizer has developed a practical method to upgrade a traditional wired doorbell into a smart home component using the ESP32-H2 microcontroller. Unlike most ESP32 models, the H2 variant lacks Wi-Fi connectivity but features an 802.15.4 radio that supports both Thread and Zigbee protocols.

The project is based on a Vistadoor ADV-100 wired doorbell. Schweizer identified a simple point where a 5V signal appears when the doorbell button is pressed. The ESP32-H2 reads this signal and sends a notification to Home Assistant, all without interfering with the doorbell's standard chime operation — it continues to ring normally.

Beyond basic notifications, the setup enables useful automations. For instance, users can configure a smart camera to capture an image every time the doorbell is pressed. The integration requires no complex rewiring and leaves the original doorbell mechanism untouched.

Schweizer explains that connecting the ESP32-H2 to trigger a Home Assistant notification whenever the doorbell rings is straightforward. The project is ideal for those looking to integrate an existing doorbell into their smart home system without purchasing new hardware. Previously, the same platform featured other doorbell upgrade projects, including a touchless design developed during the coronavirus pandemic.