How to Use Gravity: I2C ADS1115 16-Bit ADC Module: Examples, Pinouts, and Specs

The Gravity: I2C ADS1115 16-Bit ADC Module is a high-precision analog-to-digital converter (ADC) that provides 16-bit resolution over an I2C interface. This module is ideal for microcontrollers that do not have an analog-to-digital converter or when a higher precision ADC is required. Common applications include sensor reading, data logging, and industrial automation.

• Resolution: 16-bit
• Sampling Rate: Up to 860 samples per second (SPS)
• Input Voltage Range (VDD): 2.0V to 5.5V
• Analog Input Channels: 4 single-ended or 2 differential inputs
• Programmable Gain Amplifier (PGA): Up to ±6.144V
• I2C Address: Configurable (Default: 0x48)
• Operating Temperature Range: -40°C to +125°C

1. Powering the Module: Connect VDD to a 2.0V to 5.5V power supply and GND to the ground.
2. I2C Communication: Connect SCL and SDA to the I2C clock and data lines of your microcontroller, respectively.
3. Address Selection: Set the ADDR pin to the appropriate logic level to configure the I2C address if multiple devices are on the same bus.
4. Analog Inputs: Connect your analog signal to any of the A0-A3 pins. You can use these as single-ended inputs or in pairs for differential measurements.

• Ensure that the power supply voltage is within the specified range to avoid damaging the module.
• Use pull-up resistors on the SCL and SDA lines if they are not already present on the microcontroller board.
• When using differential inputs, ensure that the signals are within the common-mode range of the ADS1115.
• Avoid placing the module in environments with high electrical noise to prevent inaccurate readings.

#include <Wire.h>
#include <Adafruit_ADS1015.h>

Adafruit_ADS1115 ads;  // Create an instance of the ADS1115

void setup() {
  Serial.begin(9600);
  ads.begin();  // Initialize the ADS1115
}

void loop() {
  int16_t adc0 = ads.readADC_SingleEnded(0);  // Read from channel 0
  Serial.print("AIN0: "); Serial.println(adc0);
  delay(1000);
}

• No Data on I2C: Check connections and ensure pull-up resistors are installed. Use an I2C scanner sketch to verify the address.
• Inaccurate Readings: Ensure that the input voltage does not exceed the reference voltage set by the PGA.
• Noisy Signal: Use proper grounding and shielding techniques to minimize noise.

Q: Can I use this module with a 3.3V system? A: Yes, the ADS1115 can operate at 3.3V.

Q: How do I change the I2C address? A: Connect the ADDR pin to GND, VDD, SDA, or SCL to set the address to one of four possible values.

Q: What is the maximum voltage that can be measured? A: The maximum voltage is determined by the PGA setting, which can be up to ±6.144V.

Q: Can the ADS1115 be used with Raspberry Pi? A: Yes, it can be interfaced with a Raspberry Pi using the I2C protocol.

Q: How do I use the ALRT/RDY pin? A: This pin can be used as an alert or a conversion ready signal. Consult the ADS1115 datasheet for detailed configuration instructions.