[Tuya Smart] IoT Thermometer +540724A

0. System operation diagram

1.typec serial port circuit

The DTR pin of ch340 must be connected with a capacitor to the RST pin of Arduino before the program can be downloaded to Arduino through the serial port. (To download the program through the serial port, you need to burn the boot program first)

2.TP5400 charging management circuit

R13 resistor, the circuit in the chip manual is 1k. After testing, the light is too bright. It is recommended to increase the resistor, so it is changed to 4.7k.

R14 resistor determines the charging current

The typec port supplies power to the TP5400, charges the battery, and the battery boosts power to the entire system. When the battery is not connected, the typec port directly supplies power to the system through diode D2.

3.sht30 temperature and humidity sensor

4.Battery power measurement

5.ws2812 lamp

There is an interface left to connect ws28112 light strip

6. Infrared transmitting and receiving

7.Tuya WB3S module

Connect to Arduino virtual serial port communication, atm328p has only one hardware serial port, used for downloading programs and debugging

8. Main chip

The main chip uses atm328p, and the download interface is reserved, but it is only used when burning the boot program for the first time, because it is more convenient and faster to use the serial port to download.

9.3D diagram

10. Physical picture

The typec interface was originally soldered on, but it came off after a few uses (no problem). Due to limited conditions at home, fly line processing is required.

There is no problem with the TP5400 charging circuit and has been tested on another board. This piece is not welded. The typec port directly supplies power to the system through the D2 diode