Using ZMCT103C Current Transformer with ESPHome to Monitor AC Power Usage

ESPHome
,
1

I’m trying to set up a power meter to measure watts using one of these ZMCT103C modules. I have been trying to find online sources that could help me to get it working, but so far I haven’t been successful. The board is like the one in this listing: https://id.aliexpress.com/item/32862297933.html

1000×1000

The board has these pins:
GND
GND
OUT
VCC

I connected one of the GND pins to ground, the OUT to A0 on my ESP8266, and VCC to 5v. I tried using this example provided here https://esphome.io/components/sensor/ct_clamp.html

sensor:
  - platform: ct_clamp
    sensor: adc_sensor
    name: "Measured Current"
    update_interval: 60s

  - platform: adc
    pin: A0
    id: adc_sensor

The code runs without errors, and the sensor appears in HA. But I can’t get a correct reading from the sensor. Even without any load turned on it shows some random value instead of 0, and when I turn on my load for testing which is a light bulb, the reading changes but to a value that is incorrect. I tried calibrating it but I am still unable to get a correct reading. Did I improperly connect it? Do I need to add a resistor somewhere in the circuit? Or did I just not calibrate it right?

Has anyone ever had any experience using this sensor with ESPHome? Or maybe someone could point me to a link (website or forum) that could show how to correctly set this up? Any suggestions would be very appreciated. Thanks!

2

Where is the datasheet?

3

Hey just wondering if you got this to work?

4

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I used the above sensor without the additional electronics and it seems to work with the code you shared above. The only change I made was that my GPIO pin was 34 and I set the update interval to 1s. I haven’t tested the output for accuracy, but the sensor does seem to be sending data consistently. When there is no power flowing through the wire, it displays 0.0amp. The only problem I noticed was that after switching off the circuit it still reads between 0.03 and 0.01amp for a few seconds before going back to zero.

5

Hi, I know this is old thread. I am trying to use this sensor for doing something similar. I dont want accuracy of the reading but to detect when there is AC current present or not. I saw you have mentioned GPIO 33. Are you using esp32 in that case? From the pin outs it looks like the pin you are mentioning is Input Only pin. Can you share the circuit/connection diagram and your YAML for the benefit of the community?