Documentation

// 5kg Load Cell + HX711 - Arduino Example
// DT -> D3, SCK -> D2, VCC -> 5V, GND -> GND
// Library: "HX711" by Bogdan Necula (bogde)

#include "HX711.h"

const int DT_PIN = 3;
const int SCK_PIN = 2;

// Start with 1.0, then calibrate:
// factor = (raw with weight - raw empty) / weight in grams
float CALIBRATION_FACTOR = 1.0;

HX711 scale;

void setup() {
  Serial.begin(9600);
  scale.begin(DT_PIN, SCK_PIN);

  Serial.println("Remove all weight... taring in 3 s");
  delay(3000);
  scale.tare();                       // zero the empty platform
  scale.set_scale(CALIBRATION_FACTOR);
  Serial.println("Ready. Place a known weight to calibrate,");
  Serial.println("or start weighing if already calibrated.");
}

void loop() {
  if (scale.is_ready()) {
    // Average 10 readings for a steady value
    float grams = scale.get_units(10);
    long raw = scale.get_value(10);   // tared raw counts (for calibration)

    Serial.print("Raw: ");
    Serial.print(raw);
    Serial.print("  |  Weight: ");
    Serial.print(grams, 1);
    Serial.println(" g");
  } else {
    Serial.println("HX711 not responding - check wiring");
  }
  delay(500);
}

// 5kg Load Cell + HX711 - ESP32 Example
// DT -> GPIO 16, SCK -> GPIO 4, VCC -> 3V3, GND -> GND
// Library: "HX711" by Bogdan Necula (works on ESP32)

#include "HX711.h"

const int DT_PIN = 16;
const int SCK_PIN = 4;

float CALIBRATION_FACTOR = 1.0;  // set after calibrating

HX711 scale;

void setup() {
  Serial.begin(115200);
  scale.begin(DT_PIN, SCK_PIN);

  Serial.println("Remove all weight... taring in 3 s");
  delay(3000);
  scale.tare();
  scale.set_scale(CALIBRATION_FACTOR);
  Serial.println("Ready.");
}

void loop() {
  if (scale.wait_ready_timeout(1000)) {
    float grams = scale.get_units(10);
    Serial.printf("Weight: %.1f g\n", grams);
  } else {
    Serial.println("HX711 not responding - check wiring");
  }
  delay(500);
}

#!/usr/bin/env python3
# 5kg Load Cell + HX711 - Raspberry Pi Example (no library needed)
# DT -> GPIO 5 (pin 29), SCK -> GPIO 6 (pin 31), VCC -> 3.3V (pin 1)

import time
import RPi.GPIO as GPIO

DT, SCK = 5, 6
CALIBRATION_FACTOR = 1.0   # (raw_with_weight - raw_empty) / grams

GPIO.setmode(GPIO.BCM)
GPIO.setup(DT, GPIO.IN)
GPIO.setup(SCK, GPIO.OUT, initial=GPIO.LOW)

def read_raw():
    # Wait until the HX711 signals data ready (DT goes low)
    while GPIO.input(DT) == 1:
        time.sleep(0.001)

    value = 0
    for _ in range(24):                 # clock out 24 data bits
        GPIO.output(SCK, GPIO.HIGH)
        GPIO.output(SCK, GPIO.LOW)
        value = (value << 1) | GPIO.input(DT)

    GPIO.output(SCK, GPIO.HIGH)         # 25th pulse = channel A, gain 128
    GPIO.output(SCK, GPIO.LOW)

    if value & 0x800000:                # sign-extend the 24-bit result
        value -= 1 << 24
    return value

def read_average(n=10):
    return sum(read_raw() for _ in range(n)) / n

print("Remove all weight... taring")
time.sleep(2)
zero = read_average(20)
print("Tared. Raw zero = {:.0f}".format(zero))

try:
    while True:
        raw = read_average(10)
        grams = (raw - zero) / CALIBRATION_FACTOR
        print("Raw: {:8.0f}  |  Weight: {:8.1f} g".format(raw - zero, grams))
        time.sleep(0.5)
except KeyboardInterrupt:
    print("Stopped by user")
finally:
    GPIO.cleanup()

# 5kg Load Cell + HX711 - Pico MicroPython Example (no library needed)
# DT -> GP14, SCK -> GP15, VCC -> 3V3(OUT), GND -> GND

from machine import Pin
import time

dt = Pin(14, Pin.IN)
sck = Pin(15, Pin.OUT, value=0)

CALIBRATION_FACTOR = 1.0   # (raw_with_weight - raw_empty) / grams

def read_raw():
    while dt.value() == 1:          # wait for data ready
        time.sleep_ms(1)

    value = 0
    for _ in range(24):             # clock out 24 data bits
        sck.value(1)
        sck.value(0)
        value = (value << 1) | dt.value()

    sck.value(1)                    # 25th pulse = channel A, gain 128
    sck.value(0)

    if value & 0x800000:            # sign-extend
        value -= 1 << 24
    return value

def read_average(n=10):
    return sum(read_raw() for _ in range(n)) / n

print("Remove all weight... taring")
time.sleep(2)
zero = read_average(20)
print("Tared. Raw zero =", int(zero))

while True:
    raw = read_average(10)
    grams = (raw - zero) / CALIBRATION_FACTOR
    print("Raw: {:8.0f}  |  Weight: {:8.1f} g".format(raw - zero, grams))
    time.sleep(0.5)