0.91 inch OLED+ESP8266-12F

The PCB part is divided into three boards. The top board is the OLED screen. The middle board is the ESP8266. The bottom board is a piece used to install the watch strap.
 
1-2-3-4 PCB is a file.     
 
5*6*7*8 PCB is a file.
 
This can be done using a battery. The battery I am currently using for power supply is 701230. This battery can only be used in 1-2-3-4. The battery capacity of that file is 230 mAh and can be used for 4 hours.
 
The file of 5*6*7*8 is slightly longer than 1-2- The files of 3-4 are a little larger and the circuit part is the same, but the middle part is left to install the battery. This can hold a 102035; 1000 mAh battery. This battery can last almost a day.
 
Please do not charge it directly with a 5V power supply. I made a 4.2 volt charger myself, 
 
and then I will draw a charging circuit
 
PCB. It has been verified that it can be used. You can just build the board directly.
 
The PCB uses 4P pin headers and female headers to connect. The height is 11MM
 
and fixed. The copper pillars and screws of M2 are double-pass 11MM and single-pass 3MM or 5MM. The screws
 
are installed on the third PCB with a 3MM or 5MM strap. At TB, just buy a strap with a width of 20MM and a length of 20CM.
 
The code comes from the Internet. Thanks I only use the open source programs of the big guys for entertainment and will not use them for business.