Product name: Watch ESP32 programmable open source electronic watch Product color: black Screen size: 1.54in Product resolution: 200×200 Features: 1. low power e-paper 1.54-inch display with a resolution of 200x200 and a wide viewing angle 2.Wi-Fi and Bluetooth LE connection 3.3 Heart rate meter for axial hearing testing 4. Real-time clock with calendar and alarm functions for accurate timing 5. Built-in USB serial port to firmware, can be programmed anytime and anywhere 6. Vibration motor for alarm 7. Four buttons (use imported buttons, which feel better) 8. Open source hardware and software 9. Tons of examples and cool looks 10. Open source 3D case design 11. Built-in 3.7V 200mAh battery 12. The PCB lower cover is used to better the screen, battery and various PMP battery life on the motherboard. What to use: Watch wakes up every 60 seconds, checks the accelerometer, real-time clock, and updates the e-paper display with the latest information. WiFi is turned on during certain hours to obtain weather data. The s battery life should be 5-7 days for timekeeping only, and 2-3 days for data acquisition over WiFi. These numbers can be expanded with further optimization (e.g. sleep during off-hours, only get up when exercising/waking up, etc.) User Manual: Please scan the QR code on the product packaging Special note: Please be sure to select the hardware version V2.0 when flashing Product gross weight: 72g Package includes: Watch*1 V2.0 *1 (built-in 200mAh battery) Logic strap*1 USB data cable*1