Eink-word-clock-watch
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| Project E-ink wordclock watch | |
|---|---|
| E-ink wordclock watch | |
| Status | In progress |
| Contact | jelly |
| Last Update | 2019-04-15 |
Plan
The plan is to make an e-ink watch with a 1.54" display which will display a word clock of the current time which updates every ~ 3/5 minutes.
Requirements
- Refresh e-ink screen (ie. update word clock) every ~ 3 minutes
- Be able to set the time or sync it via WiFi/Radio?
- Capable of running for > one month
Interfaces
- SPI
- Serial for debugging / flashing?
- RTC
Parts
- e-eink screen datasheet datasheet Requiring 3.3 V, SPI and has refresh power req. of 26.4 mW with standby power of < 0.0 17 mW (0.0264/3.3 = 8mA)
- Coin cell (3V ~ 225 mAh / lithium battery small enough? (if powerful enough) 3.7 V 180 mAh 502025 Lithium Polymeer Li-Po should fit under the display, but might be too big.
MCU
- atmega 328P 320 uA "active mode", 200 nA power down and 1.3 uA power save.
- stm8s
- esp32 pico 150-10 uA
Hardware
- Display size (e-ink) 31.8mm × 37.32mm × 1.05mm
- PCB
- 3d printed case
- arm strap?
- I2C RTC chip
Prototyping
Use a e-ink breakout board with the preferred $MCU to display a simple "hello world" text every three minutes and measure the power usage.