After spending a week with Seeed Studio's reTerminal Sticky, I've found it to be a surprisingly effective and user-friendly gadget. The device is a compact, magnetic e-ink screen designed to stick easily on a fridge or other flat metal surfaces. Simply press a button, speak a message like 'Don’t forget the dog food,' and the text appears on the screen within seconds. This makes it ideal for quick reminders for family members or colleagues without the need for a smartphone or complicated setup.
Hardware under the minimalist design
The reTerminal Sticky’s hardware is tightly packed into a 3.97-inch e-paper display that supports four-level greyscale imaging. At its core is the ESP32-S3R8 microcontroller, a dual-core processor running at 240MHz. It’s equipped with 8MB of PSRAM and 32MB of flash memory, ensuring it has the computing power to handle both basic and more advanced tasks. The device also includes a PDM microphone for capturing voice input, a six-axis motion sensor, a temperature and humidity sensor, and a 750mAh battery for on-the-go use.
It connects to the world through 2.4GHz Wi-Fi and Bluetooth 5.0, offering seamless communication with smartphones and smart home networks. Battery life is estimated at around a week under normal usage. In a power-saving mode, it could theoretically last for months, though this feature is still in early testing. The reTerminal Sticky is IP40-rated, which means it can handle dust and typical kitchen conditions but won’t survive direct liquid spills.
The device’s physical dimensions are 106mm by 65.5mm and 7.3mm thick, making it slim and unobtrusive. It weighs just 70 grams and includes several N52 magnets in the corners along with an adhesive magnetic ring for non-metallic surfaces. These design elements make it easy to move and reposition. The hardware also includes three physical buttons, a buzzer for alert feedback, and a reset hole for troubleshooting.
Voice notes and open-source potential
One of the standout features of the reTerminal Sticky is its voice recognition system. By pressing the AI button, you can speak a message directly to the device. The system sends your voice to a cloud-based service — which is built on an open-source Chinese project — and converts it into text. Within a few seconds, the message appears on the e-paper display. The use of e-paper ensures the display remains active without consuming power, a major advantage for such a small device.
However, what really sets the reTerminal Sticky apart is its openness to developers. The firmware is open-source, and Seeed provides the firmware image for download, allowing developers to modify and experiment. I tried compiling my own app and successfully got it running, though the process required some tweaks and troubleshooting.
This openness extends to community-driven software projects such as ESPHome and OpenDisplay. The device’s flexibility makes it a promising platform for customization. Additionally, the Seeedash mobile app enhances its usability. Through the app, users can push to-do lists, clocks, weather updates, and even photos to the screen. The app uses Bluetooth for initial pairing and Wi-Fi for ongoing updates, ensuring the device can operate independently once connected to a network.
Value and community support
At $49.90, the reTerminal Sticky offers exceptional value for what it delivers. While an ESP32-S3 microcontroller alone can cost around $10, the reTerminal Sticky includes a touch-enabled e-ink display, built-in sensors, a microphone, and a full suite of software features for under $50. This makes it an affordable option for both casual users and those with a technical background.
The device runs a polished mobile app and has open-source firmware available, even though it’s not yet fully published as open-source. Its build quality and attention to detail are noticeable, especially when compared to other budget smart home gadgets. While the cloud-based features require an internet connection for full functionality, the core display and basic operations work well offline.
All in all, the reTerminal Sticky is a versatile, low-maintenance device that brings smart home integration without the learning curve. Whether for home use or for developers looking to expand their projects, it is a unique and well-thought-out device.