Temperature and humidity sensor

The core main control chip is ST's STM32F102C8T6, and the communication module is Tuya's WB3S. WB3S has its own dedicated SDK, which can be easily transplanted after downloading the official SDK package. The temperature and humidity sensor is selected to integrate the temperature and humidity sensor SHT30 chip.

WB3S uses the serial port connection of the microcontroller, so it is connected to the PA9 and PA10 ports; the IIC interface used by SHT30 is therefore connected to the PB13 and PB14 ports. When programming, use the USART and IIC functions that come with the microcontroller.

In addition to these core components, there is also an isp OLED display with four signal lines. A power light and a user light. The four buttons are respectively connected to the PB6/7/8/9 ports of the microcontroller. The power conversion part uses linear LDO power conversion, and the most commonly used AMS1117 series power conversion chip is selected as the device. This circuit board provides two ways to burn programs for the microcontroller. One is to use the serial port to burn using the USB-TO-TTL tool; the other is to use ST-link to burn using ST’s official burning tool. program. For the serial port burning method, there is also a toggle switch to control the level of BOOT0.

Due to welding problems, the board I made did not work properly. In addition, it was inconvenient to purchase during the Chinese New Year, and the work was soon to be handed in, so the final effect was presented with a breadboard. The actual sensor used was changed from sht30 to DHT11, Tuya smart module It was changed from wb3s to tywe1s, so the demonstration video is different from the actual picture on the cover (the cover is still a board welded before, but the welding went wrong and cannot be used).