I need to read an analog signal at about 500-1000Hz for at least 5 seconds.

I've a battery powered microphone wired into an analog and ground pin on my arduino and am trying to measure the frequency (and amplitude) of sound coming from a rijke tube

To accurately represent the sound waves I need to take samples with a frequency at least twice that of the sound I'm studying, hence the frequency above. I plan to next do FFT to find the frequencies associated with the sound sample

Having stripped down every other part of my code, I could still only get at the most 107 readings a second, as shown below

#define VOLT_CAL 269
#define CURRENT_CAL 60
unsigned long time;

EnergyMonitor emon1;             // Create an instance

void setup()

  Serial.println("LABEL, DATE, TIME,Wall Voltage,Wall Current, Mic Voltage, Time Elapsed");

void loop()
  int sensorValue = analogRead(A4);

   time = millis();

  Serial.println(time); //prints time since program started

can anyone tell me what I'm doing wrong/how I can increase the sample rate?

I've also tried to use a for loop to take my readings first, only printing them at the end but also maxed out at only 100 readings a second with the next attempt.

I've read also about preclocking, but the example codes were too complex for me to understand. A starting point in this direction would also be very much appreciated.

  • Serial prints at 9600 baud slow your loop down
    – Juraj
    Commented Mar 27, 2019 at 6:05
  • i've tried it with 115200 and even 250000, it didnt get faster
    – zueses
    Commented Mar 27, 2019 at 6:21
  • 500 samples per second for 5 seconds with 16 bit integer = 5000 byte. The arduino uno has 2000 byte sram. Do you have another arduino board?
    – Jot
    Commented Mar 27, 2019 at 7:13
  • no...is it really complex to get maybe 400Hz? it doesn't need to be integers, i just need to read analog
    – zueses
    Commented Mar 27, 2019 at 8:26
  • Use a hardware timer, for example arduino.stackexchange.com/questions/50045/… . Data sampling rates up to 100 kHz are possible!
    – MichaelT
    Commented Mar 27, 2019 at 10:00


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