This is A smart watch based on STM32 & LVGL & FreeRTOS, the total cost is about 100 RMB which equal to about $20 USD. All the hardware & software & 3D print shell are finished by my self, you can freely modify them if you want. The functions of this watch includes basic watch's function, calculator, timer, calendar, NFC card storage, games, use Bluetooth connect to smartphone to synchronize time & data, etc. It also can add some other apps. Till now, the version is v2.3.2, and the ROM cost is only about 350kb. Want see more please go to my github.
What is the battery life? I have a Huawei watch GT2 (it cost £60), and the privacy concerns do worry me - I try not to connect it to the Internet - but for a watch that supports timers, stopwatches, alarms, phone calls, sleep tracking, HR tracking, SP02 tracking, compass, local and Bluetooth music playback, always on display, and step tracking, the 14 day (without always on display) and 4 day (with always on display) battery life just makes it impossible to get anything else, especially those ‘smarter’ £200 watches that barely last a day. I also like the round display, makes it look more like an actual watch, and not a little computer on my wrist.
What is the battery life? I have a Huawei watch GT2 (it cost £60), and the privacy concerns do worry me - I try not to connect it to the Internet - but for a watch that supports timers, stopwatches, alarms, phone calls, sleep tracking, HR tracking, SP02 tracking, compass, local and Bluetooth music playback, always on display, and step tracking, the 14 day (without always on display) and 4 day (with always on display) battery life just makes it impossible to get anything else, especially those ‘smarter’ £200 watches that barely last a day. I also like the round display, makes it look more like an actual watch, and not a little computer on my wrist.