ArduinoFHT Library

fht_adc.pde guest openmusiclabs.com 9.5.12 example sketch for testing the fht library. it takes in data on ADC0 (Analog0) and processes them with the fht. the data is sent out over the serial port at 115.2kb. there is a pure data patch for visualizing the data. */

#define LOG_OUT 1 // use the log output function #define FHT_N 256 // set to 256 point fht

#include <FHT.h> // include the library

void setup() {

• Serial.begin(115200); // use the serial port TIMSK0 = 0; // turn off timer0 for lower jitter ADCSRA = 0xe5; // set the adc to free running mode ADMUX = 0x40; // use adc0 DIDR0 = 0x01; // turn off the digital input for adc0

}

void loop() {

• while(1) { // reduces jitter
  • cli(); // UDRE interrupt slows this way down on arduino1.0

    for (int i = 0 ; i < FHT_N ; i++) { // save 256 samples

    • while(!(ADCSRA & 0x10)); // wait for adc to be ready ADCSRA = 0xf5; // restart adc byte m = ADCL; // fetch adc data byte j = ADCH; int k = (j << 8) | m; // form into an int k -= 0x0200; // form into a signed int k <<= 6; // form into a 16b signed int fht_input[i] = k; // put real data into bins

    } fht_window(); // window the data for better frequency response fht_reorder(); // reorder the data before doing the fht fht_run(); // process the data in the fht fht_mag_log(); // take the output of the fht sei(); Serial.write(255); // send a start byte Serial.write(fht_log_out, FHT_N/2); // send out the data
  }

}