Experience Sharing - ACS712 on ESP32 with ESP Home for DC Measurement

[uTZFu]

Hey Rob. -thanks for your great work here - really, really cool! I tried to measure the power consumption for my setup for a whole day and finally made it :) Since I struggeled a lot and searched countless forums, i wanted to share my experience how I made it here (in case it is of help to other noobs like me):

Setup:

• Aim: Measuring power consumption of an interactive company sign.

• ESP32 Wroom Dev Board with multiple sensors (DHT, MIC, LD, Speaker, and multiple LEDs) integrated via ESP Home into Home Assistant.

• Power supply. 5v (Measured 5,18 V) with a maximum of 18 amps (unlikely to be ever drawn - standard would be up to 8 a)

• ACS712 with 20a threshold

• Wiring: ACS712 connected directly (without any voltage divider) to GPIO34

• Relevant Code used for the ESP32 within ESP Home:
  `esphome:

  libraries:

  • https://github.com/RobTillaart/ACS712.git
    includes:
  • acs712_component.h #Should be stored in your ESP Home Folder (directly - no sub folder needed)

esp32:
board: esp32dev
framework:
type: arduino

sensor:

• platform: adc #Displays the value measured at the GPIO of your ESP32 - for control purposes - can be deleted if finished
  pin: GPIO34
  name: "Stromsensor für Leistungsaufnahme"
  update_interval: 5s
  attenuation: auto #Essential part for the ESP32 since they are otherwise skipping out any voltage higher 1,01V - Alternative Calibration can be done

• platform: custom
  lambda: |-
  auto acs712_sensor = new ACS712Sensor();
  App.register_component(acs712_sensor);
  return {acs712_sensor->current_sensor, acs712_sensor->power_sensor};
  sensors:

  • name: "Stromaufnahme in Ampere"
    unit_of_measurement: A
    accuracy_decimals: 2
  • name: "Aktuelle Leistung in Watt"
    unit_of_measurement: W
    accuracy_decimals: 2
    `
    Within the File ACS712.h that I shared by @marianomd I had to do the following minor adjustments

#include "ACS712.h"

class ACS712Sensor : public PollingComponent {
   public:
    // Connected to GPIO34, 3.3 Volts being the maximum Voltage on an ESP32, 
    //  4095 being the maximum steps for 12bit (4096 is the number of steps, while 4095 is the 
    //  number of options available and 100 being the factor for my 20a Version fo the AC712 
    //  without any Voltage divider, so no recalculation needed)
    ACS712 *ACS = new ACS712(34, 3.3, 4095, 100); 

    Sensor *current_sensor = new Sensor();
    Sensor *power_sensor = new Sensor();

    ACS712Sensor() : PollingComponent(10000) {} // Changed Polling interval to 10 Seconds instead of 15 to get a faster response

    void setup() override {
        ACS->autoMidPoint();
        ESP_LOGD("acs712", "MidPoint: %d", ACS->getMidPoint());
        ACS->setNoisemV(21);
        ESP_LOGD("acs712", "Noise mV: %d", ACS->getNoisemV());
    }

    void update() override {
        float average = 0;
        int count = 5;
        for (int i = 0; i < count; i++) {
            average += abs(ACS->mA_DC()); // Two changes here: For an AC Measurement it should be mA_AC(), since I only measure DC, i changed it accordingly. the second add on was the abs() added, since I did not wanted to rewire the load but had negative values for a and p :) - Works perfectly fine for me
        }
        float amps = average / count / 1000.0;
     
        current_sensor->publish_state(amps);
        power_sensor->publish_state(amps * 5.18); // Since my power supply delivers 5.18 V and not 220 or 230 as in DC, this is required to get the correct Power consumption
    }
};

Hope this is the correct way to share this and that it helps someone with as little experience as me :-)

[RobTillaart]

Thanks for this piece of documentation.
Think I wrap it in a separate file to add to the repo so it is easier to find (maybe).

---

update

Maybe easier to make a link to this issue in the readme.md file.
The advantage is that this issue can be extended

(updated the code block in your post to get syntax highlighting, and no x-scroll bar)