Documentation

// ACS712 5A Current Sensor - Arduino Example (DC current)
// OUT -> A0, VCC -> 5V, GND -> GND, load in series through IP+/IP-

const int sensorPin = A0;
const float SENSITIVITY = 0.185;   // volts per amp (5A version)
float zeroVolts = 2.5;             // measured at startup

float readVolts(int samples) {
  long total = 0;
  for (int i = 0; i < samples; i++) {
    total += analogRead(sensorPin);
    delay(1);
  }
  return (total / (float)samples) * (5.0 / 1023.0);
}

void setup() {
  Serial.begin(9600);

  // Calibrate the zero point - no load current for these 2 seconds!
  Serial.println("Calibrating zero point, keep load OFF...");
  zeroVolts = readVolts(500);
  Serial.print("Zero = ");
  Serial.print(zeroVolts, 3);
  Serial.println(" V. Measuring...");
}

void loop() {
  float volts = readVolts(100);
  float amps = (volts - zeroVolts) / SENSITIVITY;

  Serial.print("OUT: ");
  Serial.print(volts, 3);
  Serial.print(" V | Current: ");
  Serial.print(amps, 3);
  Serial.println(" A");

  delay(500);
}

# ACS712 5A Current Sensor - ESP32 MicroPython Example (DC current)
# OUT -> 10k/20k divider -> GPIO 34, VCC -> VIN (5V)
# Divider scales 5V -> 3.33V, so multiply measured volts by 1.5

from machine import ADC, Pin
import time

adc = ADC(Pin(34))
adc.atten(ADC.ATTN_11DB)      # full 0-3.3V range

SENSITIVITY = 0.185           # volts per amp (5A version)
DIVIDER = 1.5                 # (10k + 20k) / 20k

def read_volts(samples):
    total = 0
    for _ in range(samples):
        total += adc.read_uv()
        time.sleep_ms(1)
    return total / samples / 1_000_000 * DIVIDER

# Calibrate the zero point - no load current for these 2 seconds!
print("Calibrating zero point, keep load OFF...")
zero = read_volts(500)
print("Zero = {:.3f} V. Measuring...".format(zero))

while True:
    volts = read_volts(100)
    amps = (volts - zero) / SENSITIVITY
    print("OUT: {:.3f} V | Current: {:.3f} A".format(volts, amps))
    time.sleep(0.5)

#!/usr/bin/env python3
# ACS712 5A Current Sensor - Raspberry Pi + ADS1115 Example (DC current)
# OUT -> 10k/20k divider -> ADS1115 A0, SDA/SCL -> GPIO 2/3
# Install: pip3 install adafruit-circuitpython-ads1x15

import time
import board
import busio
import adafruit_ads1x15.ads1115 as ADS
from adafruit_ads1x15.analog_in import AnalogIn

SENSITIVITY = 0.185    # volts per amp (5A version)
DIVIDER = 1.5          # (10k + 20k) / 20k

i2c = busio.I2C(board.SCL, board.SDA)
ads = ADS.ADS1115(i2c)
ads.gain = 1           # +/-4.096V range
channel = AnalogIn(ads, ADS.P0)

def read_volts(samples):
    total = 0.0
    for _ in range(samples):
        total += channel.voltage
        time.sleep(0.002)
    return total / samples * DIVIDER

print("Calibrating zero point, keep load OFF...")
zero = read_volts(300)
print("Zero = {:.3f} V. Measuring...".format(zero))

try:
    while True:
        volts = read_volts(100)
        amps = (volts - zero) / SENSITIVITY
        print("OUT: {:.3f} V | Current: {:.3f} A".format(volts, amps))
        time.sleep(0.5)
except KeyboardInterrupt:
    print("Stopped by user")

# ACS712 5A Current Sensor - Pico MicroPython Example (DC current)
# OUT -> 10k/20k divider -> GP26 (ADC0), VCC -> VBUS (5V)

from machine import ADC
import time

adc = ADC(26)
CONVERSION = 3.3 / 65535
SENSITIVITY = 0.185        # volts per amp (5A version)
DIVIDER = 1.5              # (10k + 20k) / 20k

def read_volts(samples):
    total = 0
    for _ in range(samples):
        total += adc.read_u16()
        time.sleep_ms(1)
    return total / samples * CONVERSION * DIVIDER

print("Calibrating zero point, keep load OFF...")
zero = read_volts(500)
print("Zero = {:.3f} V. Measuring...".format(zero))

while True:
    volts = read_volts(100)
    amps = (volts - zero) / SENSITIVITY
    print("OUT: {:.3f} V | Current: {:.3f} A".format(volts, amps))
    time.sleep(0.5)