ADS1232_ADC

Thread-safe Arduino/ESP32 library for the ADS1232 24-bit analog-to-digital converter, designed for load cell and weight scale applications.

Features:

• FreeRTOS background sampling task (no polling needed)
• Mutex-protected data access — safe to read from any task/core
• Ring buffer with configurable averaging window and outlier rejection
• Multi-instance support (multiple load cells on one ESP32)
• Calibration and tare helpers
• Power-down / power-up control

Based on HX711_ADC by Olav Kallhovd. Original ADS1232 port by Sofronio Chen.

Installation

PlatformIO

Add to platformio.ini:

lib_deps =
    https://github.com/decentespresso/ADS1232_ADC.git

Arduino IDE

Download this repository as a ZIP and install via Sketch > Include Library > Add .ZIP Library.

Wiring

ADS1232 Pin	ESP32 GPIO	Description
DOUT	any input	Data output (active low when ready)
SCLK	any output	Serial clock
PDWN	any output	Power down (HIGH = on, LOW = off)
A0	any output	Channel select (optional, pass 255 to skip)

Connect load cell excitation and signal lines to the ADS1232 analog inputs per the datasheet.

Quick Start

Background Sampling (recommended)

#include <ADS1232_ADC.h>

// ADS1232_ADC(dout, sck, pdwn, a0, samples, ignoreHighest, ignoreLowest)
ADS1232_ADC scale(11, 12, 13, 255, 16, true, true);

void setup() {
    Serial.begin(115200);

    scale.begin();                    // Initialize pins, power up
    scale.start(2000, true);          // 2s stabilization + tare
    scale.setCalFactor(1234.56);      // Set calibration factor
    scale.beginTask(100);             // Background sampling every 100ms
}

void loop() {
    float weight = scale.getData();   // Thread-safe, returns smoothed value
    Serial.printf("Weight: %.2f g\n", weight);
    delay(200);
}

Polling Mode

For simpler setups without FreeRTOS tasks:

#include <ADS1232_ADC.h>

ADS1232_ADC scale(11, 12, 13, 255, 16, true, true);

void setup() {
    Serial.begin(115200);

    scale.begin();
    scale.start(2000, true);
    scale.setCalFactor(1234.56);
}

void loop() {
    if (scale.update()) {             // Returns 1 when new data was read
        float weight = scale.getData();
        Serial.printf("Weight: %.2f g\n", weight);
    }
}

Dual Load Cells

ADS1232_ADC scale1(11, 12, 13, 255, 16, true, true);
ADS1232_ADC scale2(47, 48,  9, 255, 16, true, true);

void setup() {
    scale1.begin();
    scale1.start(2000, true);
    scale1.setCalFactor(1234.56);
    scale1.beginTask(100);

    scale2.begin();
    scale2.start(2000, true);
    scale2.setCalFactor(2345.67);
    scale2.beginTask(100);
}

void loop() {
    float w1 = scale1.getData();
    float w2 = scale2.getData();
    Serial.printf("Scale 1: %.2f g  Scale 2: %.2f g\n", w1, w2);
    delay(200);
}

Calibration

1. Start with no load on the scale, call tare()
2. Place a known mass on the scale
3. Call getNewCalibration(known_mass) — returns and applies the new factor
4. Store the calibration factor (e.g. in NVS/EEPROM) and restore with setCalFactor() on boot

// During calibration:
scale.tare();
// ... place known weight ...
float cal = scale.getNewCalibration(100.0);  // 100g reference weight
Serial.printf("Calibration factor: %.2f\n", cal);

// On subsequent boots:
scale.setCalFactor(cal);

API Reference

Constructor

ADS1232_ADC(uint8_t dout, uint8_t sck, uint8_t pdwn,
            uint8_t a0 = 255,       // Channel select pin (255 = unused)
            int samples = 64,        // Averaging window size (max 256)
            bool ignHigh = true,     // Reject highest sample in average
            bool ignLow = true);     // Reject lowest sample in average

Lifecycle

Method	Description
begin()	Initialize GPIO pins, power up the ADC
begin(uint8_t gain)	Initialize with specific gain setting
start(unsigned long t)	Stabilize for t ms + tare
start(unsigned long t, bool dotare)	Stabilize, optionally tare
beginTask(uint32_t intervalMs)	Start FreeRTOS background sampling task
end()	Stop background task, release resources

Data Access (thread-safe)

Method	Description
getData()	Returns smoothed, calibrated weight value
tare()	Blocking tare (up to 2s timeout)
tareNoDelay()	Non-blocking tare (captures current average as offset)
getTareStatus()	Check if tare is complete
setCalFactor(float cal)	Set calibration factor
getCalFactor()	Get current calibration factor
getNewCalibration(float known_mass)	Calculate and apply new calibration factor

Sampling Control

Method	Description
setSamplesInUse(int samples)	Change averaging window (resets buffer)
update()	Manual poll (no-op when background task running)
refreshDataSet()	Fill buffer with fresh readings (blocking, no-op when task running)

Hardware Control

Method	Description
powerDown()	Power down the ADC
powerUp()	Power up the ADC
setGain(uint8_t gain)	Set gain (affects clock pulse count)
setChannelInUse(int channel)	Select ADC channel (0 or 1)
getChannelInUse()	Get current channel

License

GPL-3.0-or-later — see LICENSE.