ESP32-watchdog

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

Here is the purchase link

Maybe in the next iteration I will choose for a smaller screen

Links

1. https://es.aliexpress.com/item/1005005295747021.html
2. https://es.aliexpress.com/item/1005004555311346.html

Buttons

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.

Capacitive touch sensor

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.

Programming port

The programming port it will be a micro-usb with the CHG340

ESP32-S3's power consumption

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.

Conceptual design

First PCB design