Brent Rubell's Adafruit MEMENTO Smart Doorbell Offers a Privacy-Respecting DIY Alternative

Brent Rubell has penned a guide to those who want something a little more private and bespoke than an off-the-shelf doorbell camera: a do-it-yourself equivalent built around the Adafruit MEMENTO Camera Board.

"This DIY doorbell won't share its data with third parties," Rubell writes of the project, which stands in for popular commercial smart doorbells from companies like Ring and Blink, "as it adheres to Adafruit's IoT Bill of Rights. Data sent from the doorbell to Adafruit IO will be stored on a private Adafruit IO feed, [and] the photos captured by the doorbell are only viewable by you."

The heart of the smart doorbell is the Adafruit MEMENTO Camera Board, an all-in-one development board that mates an Espressif ESP32-S3 microcontroller — with two 32-bit Tensilica Xtensa LX7 processor cores running at up to 240MHz and both Bluetooth Low Energy (BLE) and Wi-Fi connectivity — with an Omnivision 5640 camera module and a 240×240 1.54" color TFT display.

In Rubell's project, the MEMENTO plays host to CircuitPython — Adafruit's education-focused MicroPython port, itself a flavor of Python built with microcontrollers in mind — and connects to the Adafruit IO cloud platform. For those who subscribe to Adafruit IO+, which costs $99 per year, there's the possibility of the doorbell alerting the homeowner via SMS, while email notifications are available at the free usage tier.

When the doorbell is triggered, through the push of an illuminated arcade button, it captures an image and sends it to Adafruit IO — where, the company promises, it will be stored securely. While there's no support for video capture, live viewing, or two-way communication, it's enough to know when there's someone at your door and who they are.

The full project, including its source code and a 3D-printable housing for the camera board, push-button switch, and battery, is available on the Adafruit Learn portal.