#include "esphome.h"
 
class AJ_SR04M_Sensor : public PollingComponent, public UARTDevice, public Sensor {
 public:

  AJ_SR04M_Sensor(UARTComponent *parent) : PollingComponent(5000), UARTDevice(parent) {}

  void update() override {
  
    char frame[5];
    int pos = 0;
    float value = 0.0;

    write(0x00);
    while (available()) {
      frame[pos] = read();
      pos++;
      if(pos==5) {
        if ((frame[0] == 0xFF) && (frame[4] == 0x00) && ((frame[1]+frame[2])==frame[3])) {
          value = ((frame[1]<<8) + frame[2]) / 1000.0;
          publish_state(value);
        }
        break;
      }
    }
  }
};