Seeed Studio の半導体ガスセンサ11種類の出力をI2Cに接続するサンプル。Adafruit_ADS1115はADDRピンの接続先を変更することで最大4種類のI2Cアドレスを設定することができます。

scent_sensor.ino

#include "M5Atom.h"
#include <Adafruit_ADS1X15.h>
Adafruit_ADS1115 ads, ads2, ads3;

uint8_t
  DisBuff[2 + 5 * 5 * 3]; 

void setBuff(uint8_t Rdata, uint8_t Gdata,
             uint8_t Bdata) {
  DisBuff[0] = 0x05;
  DisBuff[1] = 0x05;
  for (int i = 0; i < 25; i++) {
    DisBuff[2 + i * 3 + 0] = Rdata;
    DisBuff[2 + i * 3 + 1] = Gdata;
    DisBuff[2 + i * 3 + 2] = Bdata;
  }
}

bool i2cActive(int8_t address) {
  Wire.beginTransmission(address);
  int error = Wire.endTransmission();
  Serial.print("I2C ");
  Serial.print(address, HEX);
  if (error == 0) {
    Serial.println(" found.");
    return true;
  }
  Serial.println(" not found.");
  return false;
}


void setup() {
  M5.begin(true, false, true);
  Serial.begin(115200);
  delay(10);
  setBuff(0xff, 0x00, 0x00);
  M5.dis.displaybuff(
    DisBuff);
  Wire.begin(26, 32);
  delay(500);
  Serial.println("M5Atom I2C Tester"); 

  i2cActive(0x48);
  if (!ads.begin(0x48, &Wire)) {
    Serial.println("Failed to initialize ADS.");
    while (1) {
      delay(100);
    }
  }

  i2cActive(0x49);
  if (!ads2.begin(0x49, &Wire)) {
    Serial.println("Failed to initialize ADS.");
    while (1) {
      delay(100);
    }
  }

  i2cActive(0x4A);
  if (!ads3.begin(0x4A, &Wire)) {
    Serial.println("Failed to initialize ADS.");
    while (1) {
      delay(100);
    }
  }
}

uint8_t FSM = 0;

void loop() {

  if (M5.Btn
        .wasPressed()) {
    switch (FSM) {
      case 0:
        setBuff(0x40, 0x00, 0x00);
        break;
      case 1:
        setBuff(0x00, 0x40, 0x00);
        break;
      case 2:
        setBuff(0x00, 0x00, 0x40);
        break;
      case 3:
        setBuff(0x20, 0x20, 0x20);
        break;
      default:
        break;
    }
    M5.dis.displaybuff(DisBuff);

    FSM++;
    if (FSM >= 4) {
      FSM = 0;
    }
  }
  delay(50);
  int16_t adc0, adc1, adc2, adc3;
  int16_t adc4, adc5, adc6, adc7;
  int16_t adc8, adc9, adc10;
  float volts0, volts1, volts2, volts3;

  adc0 = ads.readADC_SingleEnded(0);
  adc1 = ads.readADC_SingleEnded(1);
  adc2 = ads.readADC_SingleEnded(2);
  adc3 = ads.readADC_SingleEnded(3);

  adc4 = ads2.readADC_SingleEnded(0);
  adc5 = ads2.readADC_SingleEnded(1);
  adc6 = ads2.readADC_SingleEnded(2);
  adc7 = ads2.readADC_SingleEnded(3);

  adc8 = ads3.readADC_SingleEnded(0);
  adc9 = ads3.readADC_SingleEnded(1);
  adc10 = ads3.readADC_SingleEnded(2);

  Serial.print(adc0);
  Serial.print(",");
  Serial.print(adc1);
  Serial.print(",");
  Serial.print(adc2);
  Serial.print(",");
  Serial.print(adc3);
  Serial.print(",");
  Serial.print(adc4);
  Serial.print(",");
  Serial.print(adc5);
  Serial.print(",");
  Serial.print(adc6);
  Serial.print(",");
  Serial.print(adc7);
  Serial.print(",");
  Serial.print(adc8);
  Serial.print(",");
  Serial.print(adc9);
  Serial.print(",");
  Serial.print(adc10);
  Serial.println();

  M5.update();
  delay(1000);
}