LILYGO T-Watch 2020 V3

Overview

The LILYGO T-Watch 2020 V3 is an open-source ESP32-based smartwatch platform designed for developers and makers who want to build fully customized wearable applications. Unlike commercial smartwatches, the T-Watch exposes all hardware interfaces and provides a complete open-source library, allowing full control over every component.

At its core is the ESP32-D0WDQ6-V3 with 16MB Flash and 8MB PSRAM, providing ample resources for complex applications. The 1.54-inch IPS capacitive touchscreen (240x240 pixels) uses an OCA optical bonding process for improved readability and clarity. The AXP202 power management IC handles battery charging, power distribution to all subsystems, and provides a battery fuel gauge readable over I2C.

The sensor suite is impressive for a development board: the BMA423 three-axis accelerometer provides step counting and activity detection, the PCF8563 RTC maintains accurate time even during deep sleep, and the MAX98357 I2S amplifier drives an onboard 8Ω/1W speaker for audio alerts and voice output. A PDM microphone enables voice recognition and recording. An infrared transmitter allows the watch to control IR-compatible devices like TVs and air conditioners.

The custom power button requires a 2-second press to turn on and a 6-second press to force off, protecting against accidental activation. The TTGO TWatch library on GitHub provides a comprehensive abstraction layer for all hardware components, making it straightforward to build custom watch faces, fitness trackers, remote controls, and IoT controller interfaces.

Firmware Compatibility

• Arduino: Primary development platform with the TTGO TWatch Library providing full hardware abstraction.
• MicroPython: Community support available for basic watch functionality.
• ESP-IDF: Supported for advanced power management and hardware control.

Flashing Guide

1. Connect the T-Watch 2020 V3 to your computer using the magnetic charging cable (which also carries data).
2. In Arduino IDE, install the TTGO TWatch Library from the Library Manager or GitHub.
3. Select "TTGO T-Watch" as the board (after installing the ESP32 board package).
4. Choose the correct COM port and upload your sketch.
5. For custom firmware, clone the TTGO TWatch Library from https://github.com/Xinyuan-LilyGO/TTGO_TWatch_Library and use the provided examples as a starting point.
6. To enter bootloader mode, hold the crown button while connecting the charging cable.