APADevices PHX ADS1015 Library

Arduino library for pH and ORP/Redox measurements using ADS1015 ADC. Originally designed for APADevices PHX hardware but compatible with any pH/ORP analog circuits using ADS1015.

Features

• Non-blocking operation with state machine design
• Two-point calibration for both pH and ORP
• Configurable sampling and filtering
• Built-in error detection
• Rolling average support
• No external dependencies (uses only Wire.h)
• pH range: 0-14 with validation
• ORP range: 0-1000mV with validation (configurable)

Installation

1. Download the library files
2. Create folder APAPHX_ADS1015 in your Arduino libraries directory
3. Copy all files into the created folder
4. Restart Arduino IDE

Hardware Setup

Connect your ADS1015 to Arduino:

• VDD to 3.3V or 5V
• GND to GND
• SCL to SCL (A5 on most Arduino boards)
• SDA to SDA (A4 on most Arduino boards)
• ADDR pin:
  • GND for address 0x48
  • VDD for address 0x49
  • SDA for address 0x4A
  • SCL for address 0x4B

Basic Usage

#include "APAPHX_ADS1015.h"

// Create instances
ADS1015 ads1015PH(ADDRESS_49);  // pH sensor
ADS1015 ads1015RX(ADDRESS_48);  // ORP sensor

void setup() {
    ads1015PH.begin();
    ads1015RX.begin();

    //Set preferred ADS gains aligned with your needs
    ads1015PH.setGain(ADS1015_REG_SET_GAIN1_4_096V);
    ads1015RX.setGain(ADS1015_REG_SET_GAIN1_4_096V);
}

void loop() {
    // Configure reading
    PHXConfig config = {
        .type = "ph",        // "ph" or "rx"
        .samples = 100,      // samples per reading
        .delay_ms = 10,      // delay between samples
        .avg_buffer = 3      // rolling average size
    };
    
    // Take reading
    ads1015PH.startReading(config);
    while(ads1015PH.getState() != PHXState::IDLE) {
        ads1015PH.updateReading();
    }
    
    float ph = ads1015PH.getLastReading();
}

Calibration

Two-point calibration is required for accurate readings:

// pH Calibration (using pH 4 and 7 buffers by default, configurable - see bellow)
PHX_Calibration phCal;

// First point (pH 4)
phCal.ref1_mV = ads1015PH.calibratePHXReading("ph");
phCal.ref1_value = 4.0;

// Second point (pH 7)
phCal.ref2_mV = ads1015PH.calibratePHXReading("ph");
phCal.ref2_value = 7.0;

ads1015PH.calibratePHX("ph", phCal);

// ORP Calibration (using 475mV and 650mV solution buffers by default, edit if wanted)
PHX_Calibration orpCal;
orpCal.ref1_mV = ads1015RX.calibratePHXReading("rx");
orpCal.ref1_value = 475.0;
orpCal.ref2_mV = ads1015RX.calibratePHXReading("rx");
orpCal.ref2_value = 650.0;
ads1015RX.calibratePHX("rx", orpCal);

Error Handling

PHXError error = sensor.getLastError();
switch(error) {
    case PHXError::NONE: break;
    case PHXError::PH_LOW: // pH below 0
    case PHXError::PH_HIGH: // pH above 14
    case PHXError::ORP_LOW: // ORP below 0mV
    case PHXError::ORP_HIGH: // ORP above 1000mV
}

Examples

The library includes three example sketches:

1. APAPHX_basic_example: Simple continuous reading with calibration
2. APAPHX_intermediate_example: Separate pH/ORP calibration with rolling average
3. APAPHX_advanced_example: Full feature demonstration including error handling

Available Gain Settings

• ADS1015_REG_SET_GAIN0_6_144V: ±6.144V (recommended for APA Devicess pH module and for classic ph analog module as well)
• ADS1015_REG_SET_GAIN1_4_096V: ±4.096V (recommanded for APA Device ORP module)
• ADS1015_REG_SET_GAIN2_2_048V: ±2.048V
• ADS1015_REG_SET_GAIN4_1_024V: ±1.024V
• ADS1015_REG_SET_GAIN8_0_512V: ±0.512V
• ADS1015_REG_SET_GAIN16_0_256V: ±0.256V

License

This library is released under the MIT License.

Author

APADevices [@kecup]

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Support

No support included! Use as is or leave it. Sorry about that.