Read-Sensor-Resistances/nano_c_mk1/nano_c_mk1.ino

#include <Adafruit_ADS1X15.h>  // https://github.com/adafruit/Adafruit_ADS1X15

#define WAIT_TIME      1000UL  // default wait time each value read
#define ADS_MAX        4       // # of analog input pins of an ADS1115
#define VOLTAGE_RANGE  6.144f  // ADS1115 default gain (+/- 6.144V). Change this number smaller will reduced its actual magnutude, and vice versa
#define CONST_I2C      32768   // a constant value

unsigned long currTime;  // non-blocking timer
Adafruit_ADS1115 adc;
int i;  // loop iterators
float adcReadings[ADS_MAX];  // buffer to hold all values read from an adc

void setup() {
  Wire.begin();
  Serial.begin(19200);
  adc.begin();
  currTime = millis();
}

void loop() {
  // TODO: The current reading is too slow beacuse `readADC_SingleEnded` is a blocking function. Not ideal on real-application.
  if (millis() - currTime >= WAIT_TIME) {  // non-blocking time delay
    for (i = 0; i < ADS_MAX; i++) {
        adcReadings[i] = adc.readADC_SingleEnded(i) * VOLTAGE_RANGE / CONST_I2C; // this part can just read the adc. The conversion part could done in the Python code for flexibility
    }
    Serial.print("[");
    // two seperate for loops for read adc and serial write to make it seems less laggy. again, this is completly wrong and need to replace it to something more non-blocking
    for (i = 0; i < ADS_MAX; i++) {
      Serial.print(adcReadings[i]);
      if (i != ADS_MAX - 1) {
        Serial.print(", ");
      }
    }
    Serial.println("]");
    currTime = millis();  
  }
}