AnalogAveraging.ino

Shows how averaging steadies a reading: for averaging 1, 4, 8, 16 and 32, takes 100 readings of A0 and A3 and prints the lowest, the highest and the spread, in 12-bit ADC steps.

analogReadAveraging() applies to every analog pin: A3-A5 average inside the external ADC, A0-A2 take the samples one after another.

Wiring

Optional: a steady voltage, e.g. a potentiometer wiper, on A0 (0-3.3 V) and A3 (0-2.048 V).

Output

Serial Monitor at 115200 baud, for example:

Averaging 1:   A0 2041-2058 (spread 17)   A3 1022-1025 (spread 3)
Averaging 32:   A0 2048-2050 (spread 2)   A3 1023-1023 (spread 0)

// Shows how averaging steadies a reading. For each setting, takes 100
// readings of A0 and A3 and prints the lowest, the highest and the spread
// between them (in ADC steps). Connect a steady voltage, e.g. a potentiometer
// wiper, to A0 (0-3.3 V) and A3 (0-2.048 V), or leave them as they are.
//
// analogReadAveraging() applies to every analog pin: A3-A5 average in the
// external ADC itself, A0-A2 take the samples one after another.
 
const int READINGS = 100;
const uint8_t SETTINGS[] = {1, 4, 8, 16, 32};
 
void printSpread(const char* name, pin_size_t pin) {
    int lowest = 4095;
    int highest = 0;
    for (int i = 0; i < READINGS; i++) {
        const int value = analogRead(pin);
        if (value < lowest) lowest = value;
        if (value > highest) highest = value;
    }
    Serial.print(name);
    Serial.print(" ");
    Serial.print(lowest);
    Serial.print("-");
    Serial.print(highest);
    Serial.print(" (spread ");
    Serial.print(highest - lowest);
    Serial.print(")   ");
}
 
void setup() {
    Serial.begin(115200);
    while (!Serial) {}
    analogReadResolution(12);  // 0-4095, to see the small changes
}
 
void loop() {
    for (uint8_t samples : SETTINGS) {
        analogReadAveraging(samples);
        Serial.print("Averaging ");
        Serial.print(samples);
        Serial.print(":   ");
        printSpread("A0", A0);
        printSpread("A3", A3);
        Serial.println();
    }
    Serial.println();
    delay(3000);
}