The TinyWatch S3 is a versatile smartwatch powered by the ESP32-S3 microcontroller, which includes 8MB of quad SPI flash storage and an additional 2MB of QSPI PSRAM. It features a 240 x 280 LCD with capacitive touch functionality, supported by a CST816T module.
The device is equipped with multiple sensors such as a 6-axis inertial measurement unit, a magnetometer, and a MEMS microphone. For connectivity and power, it uses a USB-C port that facilitates power, programming, and charging for a connected LiPo battery, available in 250mAh or 500mAh capacities. Despite the ongoing firmware development, it is operational as a watch and can serve as a daily driver.
Characterized as a “wrist-wearable ESP32-S3 development board,” the TinyWatch S3 does not include pin headers and is not suitable for breadboarding. The hardware design is open-source, making it ideal for firmware development, testing, and various general projects. Its primary use is for software development rather than as a conventional consumer device.
Firmware development for the TinyWatch S3 occurs within the PlatformIO environment and demands significant expertise in C++ and the ESP32 Arduino Core framework.
Currently, the firmware supports basic functions such as digital and analog time display, weather and battery status widgets, and a simple app framework including an audio visualization app, a compass, and a basic “Hello World” app. Apps are integrated into the firmware instead of being standalone, and a web interface is available for configuration tasks like entering API keys for OpenWeather.
The TinyWatch S3’s specifications include the ESP32-S3 SoC with a dual-core 32-bit LX7 microcontroller running up to 240 MHz, 512KB SRAM, and 8MB of QSPI flash. It supports Wi-Fi 4 and Bluetooth 5.0 (LE) with 45 programmable GPIOs, and additional memory is provided by 2MB of QSPI PSRAM.
The watch features a 240 x 280 ST7789 display with capacitive touch, USB-C for power and programming, and reverse USB back-feed protection. Other components include an I2C low-power RTC, a 6-axis IMU, a magnetometer, and a MEMS microphone, along with a magnetic buzzer, a haptics motor, and various buttons for power and reset functions.
Available for purchase at $59 from Lectronz or the Unexpected Maker website, the TinyWatch S3 comes pre-assembled in a 3D-printed case. However, it does not include a watch band or battery. Its GitHub repository provides access to KiCAD design files, schematics, firmware files, and case designs, alongside example projects. It stands among other ESP32-based smartwatches such as the LilyGO T-Watch S3 and MutantW V1.
