Documentation

// WCS1700 - Read current in amps on Arduino
// Wire the load conductor through the WCS1700 hole.
// Aout to A0, Dout (optional) to D2.

const int aoutPin = A0;
const int doutPin = 2;

const float VREF        = 5.0;     // Arduino ADC reference
const float SENSITIVITY = 0.032;   // ~32 mV per amp
float       offsetVolts = 2.5;     // calibrated below

void calibrateZero() {
  long sum = 0;
  for (int i = 0; i < 200; i++) { sum += analogRead(aoutPin); delay(2); }
  offsetVolts = (sum / 200.0) * VREF / 1023.0;
}

void setup() {
  Serial.begin(9600);
  pinMode(doutPin, INPUT);
  delay(500);
  calibrateZero();
  Serial.print("Zero offset: "); Serial.print(offsetVolts, 3); Serial.println(" V");
}

void loop() {
  int raw = analogRead(aoutPin);
  float volts = raw * VREF / 1023.0;
  float amps  = (volts - offsetVolts) / SENSITIVITY;

  Serial.print("V="); Serial.print(volts, 3);
  Serial.print("V  I="); Serial.print(amps, 2); Serial.print(" A");
  if (digitalRead(doutPin) == LOW) Serial.print("  [ALARM]");
  Serial.println();
  delay(250);
}

// WCS1700 on ESP32 - measure current with a 2:1 divider on Aout
// Aout -> 10k -> GPIO34 -> 10k -> GND

const int  aoutPin     = 34;
const float VREF       = 3.3;       // ADC reference
const float DIVIDER    = 0.5;       // 2:1 voltage divider
const float SENSITIVITY = 0.032;    // V/A
float       offsetVolts = 1.25;     // 2.5V * 0.5 (divided)

void setup() {
  Serial.begin(115200);
  analogReadResolution(12);  // 0 - 4095
  delay(500);

  long sum = 0;
  for (int i = 0; i < 500; i++) { sum += analogRead(aoutPin); delay(2); }
  offsetVolts = (sum / 500.0) * VREF / 4095.0;
}

void loop() {
  int raw = analogRead(aoutPin);
  float vAtPin = raw * VREF / 4095.0;
  float vReal  = vAtPin / DIVIDER;
  float amps   = (vReal - (offsetVolts / DIVIDER)) / SENSITIVITY;

  Serial.printf("Vpin=%.3f  Vreal=%.3f  I=%.2f A\n", vAtPin, vReal, amps);
  delay(250);
}

#!/usr/bin/env python3
# WCS1700 + ADS1115 on Raspberry Pi
# pip install adafruit-circuitpython-ads1x15

import time
import board, busio
from adafruit_ads1x15.ads1115 import ADS1115
from adafruit_ads1x15.analog_in import AnalogIn

i2c = busio.I2C(board.SCL, board.SDA)
ads = ADS1115(i2c)
ch  = AnalogIn(ads, 0)            # WCS1700 Aout -> A0

SENSITIVITY = 0.032               # V/A

# Auto-zero
samples = [ch.voltage for _ in range(200)]
offset = sum(samples) / len(samples)
print("Zero offset: {:.3f} V".format(offset))

while True:
    v = ch.voltage
    amps = (v - offset) / SENSITIVITY
    print("V={:.3f}  I={:.2f} A".format(v, amps))
    time.sleep(0.25)