Spectra is a JavaScript-based hackable smartwatch based on the ESP32-S3 WiFi and Bluetooth microcontroller that aims to offer the quality of high-end consumer smartwatches with the repairability of a maker-targeted device.
The Spectra smartwatch combines the ESP32-S3 microcontroller with a Nordic Semi nRF52832 co-processor to optimize the battery life. The ESP32-S3 is maxed out with 8MB of RAM and 32MB of external flash memory, and the microSD card slot in the watch supports up to a 512GB memory card.
It shares a similar concept with the Bangle.js and the Bangle.js 2 customizable smartwatches. According to the maker, Spectra is not bound to be fully open-source, since the project uses “external proprietary code [they] aren’t allowed to share.” They plan to publish Arduino libraries and hardware design files, but there is no live GitHub repository yet.
Other hackable smartwatches include the TinyWatch S3, the ZSWatch, and the Sensor Watch Pro.
Spectra specifications:
- MCU – ESP32-S3 SoC, dual-core XTensa LX7 @ up to 240 MHz; 512KB SRAM; Integrated 2.4GHz Wi-Fi and BLE
- Co-processor – Nordic Semiconductor nRF52832 ARM Cortex-M4F @ 64 MHz with 512KB Flash, 64KB RAM, Bluetooth 5.4 LE connectivity
- Memory – 8MB RAM
- Storage – 32MB flash, microSD card slot (supports up to 512GB)
- Display – 368 x 448 OLED display
- Sensors
- Magnetic encoder
- Magnetometer
- Gyroscope & accelerometer
- PPG (photoplethysmogram) sensor
- Misc – Speaker, Microphone, 4x user hotkeys (including crown), 4x contact pins on the rear (USB and charging), aluminum housing
- Debugging/Programming – Full SWD debug port on the rear of the watch
- Battery – TBD
- Dimensions – 42.60 x 35 x 10.95mm watch body, with standard 22mm watch straps
SpectraOS is the customizable smartwatch’s operating system and supports “coordinate-based GUI, modular drivers, and dynamic features.” It is designed to be backward compatible with future Spectra smartwatches and will run first-party and third-party applications downloadable from an app store. The company also offers a software development platform that supports live coding with a simulation of the smartwatch.
The Spectra project is live on Kickstarter and more than halfway to its funding goal of $32,559. There are three available rewards: Super Early Bird (about $216), Early Bird (about $260), and Spectra (about $282). Optional add-ons include micro SD cards, a watch box, and stainless steel housing. Orders are expected to ship by July 2025.
Via Hackster.io
Tomisin is a writer specializing in hardware product reviews, comparisons, and explainers. He is very passionate about small form factor and single-board computers.
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I wonder why they have two wireless MCUs.. I guess the esp is for display, UI, and WiFi, and the nrf for ble and peripheral data collection.
All in all, sounds like a neat, yet beefy, little package