This watch will be a multipurpose watch, that will have some kind of Espressif's MCU because it's cheap a come with good features like Bluetooth and Wi-Fi.
I want to have the more compact design, with that said, the screen and battery define the size watch.
Searching on Aliexpress I found the next options
| ID | Technology type | Consumption (mAh) - Voltage (V) | Communication interface | Size | Price | Resolution |
|---|---|---|---|---|---|---|
| 1 | TFT-LCD | 95mAh-5v | UART | 47,5mm diameter x 27,0mm de height | 371 MX | 240px |
| 2 | Electronic paper screen Monochrome | 0.15mAh | - | 1.28in | 574.29 MX 2 units | 128px |
I decided to use the next LCD screen
Maybe in the next iteration I will choose for a smaller screen
- https://es.aliexpress.com/item/1005005295747021.html
- https://es.aliexpress.com/item/1005004555311346.html
For applications control it is needed to have some kind of inputs, like in common watches,with the hour configured through buttons. One option is to have capacitive buttons or micro-buttons.
Following this document https://ww1.microchip.com/downloads/en/AppNotes/Capacitive-Touch-Sensor-Design-Guide-DS00002934-B.pdf This type of sensor touch it seems the best option, it is called "slide sensor", at "Extend Interpolation" form.
The programming port it will be a micro-usb with the CHG340
| Mode | Power consumption |
|---|---|
| Recommended | 500(mA) |
| deep sleep | 7-8(uA) |
| light sleep | 240(uA) |
| wifi | 355mA |
In the case that I want to use Wi-Fi with another application running for three hours on a day and with powered on screen.
