TinyWATCH S3 P7 is an innovative, open-source smartwatch designed specifically for tech enthusiasts and embedded developers. Created by Unexpected Maker, this device arrives pre-assembled but is designed for easy disassembly, catering to those who wish to hack or modify its hardware.

Powered by an Espressif ESP32-S3 Dual Core MCU operating at 240 MHz, the smartwatch includes 8MB of QSPI Flash and 2MB of additional PSRAM. It supports 2.4GHz Wi-Fi (802.11b/g/n), Bluetooth 5, BLE, and Mesh, making it highly connected and versatile.

The device features a small 240×280 ST7789 display enhanced by a capacitive touch sensor (CST816T) for responsive user interaction. This setup facilitates a rich, intuitive user experience, crucial for developers testing their applications.

Motion tracking is enabled by a 6 Axis IMU (BMI270), relevant for applications such as step counting and activity recognition. Additionally, a magnetometer (MMC5603) is included to enhance orientation tracking, which is useful for navigation.

Audio interaction is handled by an I2S MEMS Microphone (ICS-43434), allowing for sound capture for voice commands and audio analysis applications. A haptics motor (DRV2605L) provides tactile feedback through vibrations, enhancing the user interaction with alerts and notifications.

For efficient operation, the gadget integrates a battery fuel gauge (MAX1704X) that accurately monitors the battery status, providing essential data on battery health and charge levels. Additionally, a low power RTC (RV-3028-C7) is included to maintain time with precision.

In its latest iteration, P7, TinyWATCH has undergone significant upgrades such as a new haptics driver and optimized PCB layout to accommodate a larger haptic motor. The battery connection now requires direct soldering to the PCB, facilitating the use of larger battery capacities.

The firmware for TinyWATCH S3 P7 is currently in the early alpha stage and is being developed using PlatformIO with C++ on the ESP32 Arduino Core framework. Currently, it supports displaying time in both digital and analog formats and features a basic application framework that includes an audio visualizer and a compass. Development is actively continuing with intentions for further enhancements, although there are no plans to establish an App Store; all applications will be integrated directly into the core framework.

While TinyWATCH can be worn daily, its primary purpose is as a development platform for wearable hardware. Accurate timekeeping and additional functionalities like step counting and audio visualizations require a Wi-Fi setup.

Design files, case files, and firmware are readily available on the TinyWATCH S3 GitHub repository, providing resources for both past and current hardware revisions.

Further information

Priced at $59.00, TinyWATCH S3 P7 is available in limited quantities at the Unexpected Maker Shop. It doesn’t include a battery due to shipping regulations, so users will need to provide their own. The design accommodates larger batteries for improved haptic feedback and extended charge intervals. This product ships in a 3D printed case compatible with standard Apple Watch bands, facilitating ease of use during development.