First ESPHome Custom Sensor ZMPT101B Voltage Sensor

ESPHome
9

@Stringyb92 , here you go. You might be able to put together better formulas than I have in the custom module - there are others out there.

  1. snippet from my device config
esphome:
  name: mainsvoltagemeter
  includes:
    - zmpt101b_custom_sensor.h

sensor:
  - platform: custom
    lambda: |-
      auto my_sensor = new ZMPT101BSensor();
      App.register_component(my_sensor);
      return {my_sensor};
    sensors:
      name: "Mains Voltage"
      unit_of_measurement: V
      accuracy_decimals: 0
      state_class: "measurement"
  1. The custom module: zmpt101b_custom_sensor.h - this goes in the esphome folder
#include "esphome.h"
#include <Arduino.h>

#define VMAX 250
#define FREQUENCY 50
#define CALIBRATE_READ 130
#define CALIBRATE_ACTUAL 225
#define ZERO_VAC 788

class ZMPT101BSensor : public PollingComponent, public Sensor {
 public:
  // constructor
  ZMPT101BSensor() : PollingComponent(1000) {}

  float get_setup_priority() const override { return esphome::setup_priority::HARDWARE; }

  void setup() override {
    // This will be called by App.setup()
  }

  void update() override {
  // This will be called every "update_interval" milliseconds.

    uint32_t period = 1000000 / FREQUENCY;
    uint32_t t_start = micros();
    uint32_t Vsum = 0, measurements_count = 0;
    int32_t Vnow;

    while (micros() - t_start < period) {
      Vnow = analogRead(A0) - ZERO_VAC;
      Vsum += Vnow*Vnow;
      measurements_count++;
    }

    float Vrms = sqrt(Vsum / measurements_count) / CALIBRATE_READ * CALIBRATE_ACTUAL;
    publish_state(int(Vrms));

  }
};
2 Likes