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esp32_temperature and humidity station

A simple ESP32 thermometer and hygrometer

Project Overview:
This project is a thermometer and hygrometer based on the ESP32-C3 microcontroller. It can detect the temperature and humidity in a room and is directly connected to HA (Home Assistant). Because we want it to be very discreet, the light will only turn on when it is charging and will not be lit in other scenarios.
Project Functionality:
This design uses esphome firmware, so you basically don't need to write any code to drive the sensor. You only need to configure the esphome scripts, and it will automatically add the sensor to the HA.
My configuration is shown in the image. I originally planned to add a BH1750, but esphome couldn't initialize the sensor. This is probably due to my hardware design or soldering issues. This device is very small, and you can hardly see the pin soldering. After several attempts, I gave up.
Project Parameters

: This design uses the ESP32-C3-WROOM-02-N4 module. I happened to get 10 of them for free during a previous Espressif promotion, so I used them.
This design uses the Guangzhou Aosong AHT20 temperature and humidity sensor. This device communicates via the IIC bus. The humidity sensor has an accuracy of ±2%, and the temperature sensor has an accuracy of ±0.3℃, which is very high.
Battery management uses the LGS5600C, a dischargeable battery management chip.

Principle Analysis (Hardware Description):
This project consists of the following parts: power supply, sensor, main control, and battery management.
The power supply section
is shown in the figure. This is a DC-DC step-down circuit using the SY8089 chip. This chip is inexpensive, has a wide input voltage range, and can output up to 2A. Its peripheral circuit is also very simple, requiring only one inductor, three capacitors, and two resistors. One of the resistors is used to configure the output voltage. I have set it to 3.3V output. However, a drawback is that this chip is a step-down chip, so the output voltage will also decrease when the input voltage is low.
The battery
management chip used is LGS5600C, but the problem I encountered is that the chip outputs 5V normally when the battery is charging, but there is no output when the battery is not in use, only about 0.2V. I don't know why yet. I need to contact the manufacturer's technical support when I have time. The sensor
part
is relatively simple; just build the basic peripheral circuit according to the manual. However, one thing to note is that when laying out the temperature and humidity sensors, you should cut grooves around them as much as possible to avoid interference from the MCU or other heat-generating devices. My design was a bit rushed, so please don't imitate it.
The official manual also describes it this way. The main
control
part is relatively simple because the ESP32-C3 has USB download functionality, which saves one CH340K chip (another day of cost savings). The peripheral circuit of the chip is also built according to the minimum system given in the datasheet.
To reduce the difficulty of hardware soldering, the capacitors and resistors used are all 0603 packages.
Software code
: I2C: #Configure IIC bus
sda: GPIO6 #sda data line
scl: GPIO7 #scl clock line
scan: true # Whether to enable IIC address scanning
id: bus_a # Bus ID
sensor: # Sensor-
platform: aht10 # Sensor type
variant: AHT20 # Sensor model
temperature: # Temperature setting
name: "Temperature" # Temperature name (entity name displayed in HA)
humidity: # Humidity setting
name: "Humidity" # Humidity name (entity name displayed in HA)
update_interval: 1s # Update time
The code part is just a YAML configuration, after all, esphome has provided the driver, so why not use it? Note: The PCB of the temperature and humidity sensor needs to be grooved around the perimeter. Assembly Process : The casing is still under design and printing has not yet started. Battery management is also not yet finalized, so it will take some time before
the main assembly is complete. Physical Image