Simulating DHT22 sensor HELP

[LEDuser]

Hi everybody!

I'm struggling with simulating DHT22 sensor in esphome. I'm measuring water tank level and temperature and I need to send data to shelly (cloud data for few users). I had similar simulation working with STM32 for few years but now I switched to ESP32 because I need few other sensors reporting to homeassistant.

I tried to make it with binary sensor but i don't get timing right. The problem I have is delay after falling or rising edge. I also tried to get falling edge and wait to rising edge but somehow it's always LOW in lambda. Probably because GPIO sensor is not updated while in lambda?

I was thinking about using some other method to detect input and then change to output and send data to same GPIO.

This is the protocol. Green pulses are from shelly addon and blue is the response and data.

`output:

• platform: gpio
  id: DHT22s
  pin:
  number: GPIO9
  inverted: True
  mode:
  output: True
  open_drain: True
  pullup: True

binary_sensor:

• platform: gpio
  id: DHT22request
  name: "DHT22 Request"
  pin:
  number: GPIO8
  mode:
  input: True
  pullup: True
  filters:

  • invert:
    #internal: True
    on_release:
    #min_length: 16ms
    #max_length: 20ms
    then:
    lambda: |-

    //delayMicroseconds(18000);
    
    
    delayMicroseconds(20);
    
    // Pull the line LOW for 80us to respond
    id(DHT22s).turn_on();
    delayMicroseconds(80);
    
    // Pull the line HIGH for 80us to indicate readiness
    id(DHT22s).turn_off();
    delayMicroseconds(80);
    
    // Simulate sending sensor data
    uint8_t humidity_integral = 50; // Example humidity integral data
    uint8_t humidity_decimal = 0;   // Example humidity decimal data
    uint8_t temperature_integral = 25; // Example temperature integral data
    uint8_t temperature_decimal = 0;   // Example temperature decimal data
    uint8_t checksum = humidity_integral + humidity_decimal + temperature_integral + temperature_decimal;
    
    for (int i = 7; i >= 0; i--) {
        id(DHT22s).turn_on();
        delayMicroseconds(50); // Delay between bits
        id(DHT22s).turn_off();
        if (humidity_integral & (1 << i)) {
            delayMicroseconds(70); // Delay for '1' bit
        } else {
            delayMicroseconds(28); // Delay for '0' bit
        }
    }
    
    for (int i = 7; i >= 0; i--) {
        id(DHT22s).turn_on();
        delayMicroseconds(50); // Delay between bits
        id(DHT22s).turn_off();
        if (humidity_decimal & (1 << i)) {
            delayMicroseconds(70); // Delay for '1' bit
        } else {
            delayMicroseconds(28); // Delay for '0' bit
        }
    }
    
    for (int i = 7; i >= 0; i--) {
        id(DHT22s).turn_on();
        delayMicroseconds(50); // Delay between bits
        id(DHT22s).turn_off();
        if (temperature_integral & (1 << i)) {
            delayMicroseconds(70); // Delay for '1' bit
        } else {
            delayMicroseconds(28); // Delay for '0' bit
        }
    }
    
    for (int i = 7; i >= 0; i--) {
        id(DHT22s).turn_on();
        delayMicroseconds(50); // Delay between bits
        id(DHT22s).turn_off();
        if (temperature_decimal & (1 << i)) {
            delayMicroseconds(70); // Delay for '1' bit
        } else {
            delayMicroseconds(28); // Delay for '0' bit
        }
    }
    
    for (int i = 7; i >= 0; i--) {
        id(DHT22s).turn_on();
        delayMicroseconds(50); // Delay between bits
        id(DHT22s).turn_off();
        if (checksum & (1 << i)) {
            delayMicroseconds(70); // Delay for '1' bit
        } else {
            delayMicroseconds(28); // Delay for '0' bit
        }
    }
    id(DHT22s).turn_off(); // Finish transmission
    
    //ESP_LOGD("custom", "Data Sent");`