Introduction

In this post we talk about the Analogic-Digital Converter (ADC) 16-bits module ADS1115 for Arduino industrial automation controller. You will find some information about the module and the way to connect with Arduino automation and read analog values.

Requeriments

ADC 16-bits module ADS1115 >>

ADS1115 Adafruit library >> 

M-Duino >> or Ardbox >> family 

ADS1115

The ADS1115 is a precision analog-to-digital converter with 16-bits of resolution offered in an ultra-small, leadless WFN_10 package or an MSOP-10 package. It is designed with precision, power and ease of implementation in mind. Data are transferred via an I2C-compatible serial interface; four I2C slave addresses can be selected.

Technical features

Connections 

According to Hardware Configuration (page 11) of the ADS115 Datasheet. The connections are the following:

Arduino Mega

Arduino mega2560 rev3 >>

M-Duino PLC 

Arduino PLC Ethernet >>

Library

To be able to read the Analog Pins values in a more confortable and easy way, we advice to use the Adafruit ADS1115 library. Here you gave the link: Adafruit_ADS1115.

Once you have downloaded the .zip file, in the Arduino IDE go to Sketch -> Include Library -> Add .ZIP Library... You will find the .zip file Adafruit_ADS1X15-master in the Downloads folder. Now we can include the Adafruit_ADS1015.h header in our programs in oder to use the functions that we have available. 

Code

The same code for Arduino Mega or M-Duino. 

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

Adafruit_ADS1115 ads;
const float multiplier = 0.0001875F;

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

  // There are different GAINs
  // ads.setGain(GAIN_TWOTHIRDS);  +/- 6.144V  1 bit = 0.1875mV (default)
  // ads.setGain(GAIN_ONE);        +/- 4.096V  1 bit = 0.125mV
  // ads.setGain(GAIN_TWO);        +/- 2.048V  1 bit = 0.0625mV
  // ads.setGain(GAIN_FOUR);       +/- 1.024V  1 bit = 0.03125mV
  // ads.setGain(GAIN_EIGHT);      +/- 0.512V  1 bit = 0.015625mV
  // ads.setGain(GAIN_SIXTEEN);    +/- 0.256V  1 bit = 0.0078125mV

  ads.setGain(GAIN_TWOTHIRDS);  
  ads.begin();
}

void loop() {
  int16_t adc0;

  adc0 = ads.readADC_SingleEnded(0);
  Serial.print("Analog 0: "); 

  // Read value from 0 to 32767 from 16 bits register, so it's necessary to convert to real value
  // by multiplying by 0.0001875 (GAIN)

  Serial.println(adc0 * multiplier);
  delay(1000);
}

To test the program we connected the Power Supply to A0 at 2.5 V. That's the result in the Serial Monitor:

• With multiplier = 1. Decimal value of the 16 bit register. 

• With Multiplier = 0.0001875F. Decimal value of the 16 bit register multiplied by the appropriate multiplier to get the real value representation in V units. 

It is also possible to use the the module ADS1115 to Raspberry Pi.