Thank you for coming up with a for loop for me. J goes to 127 and I am not sure what fft_log_out is printing in relation to j. I got frequencies printed from this code written by hongp (forum.arduino.cc/index.php?topic=175679.new#new) but his code is made for a specific school project involving pumps. His code prints just one freq at a time and its kinda slow, but it pushes out a freq.
When I first tried your for loop, tmd3, I got the same type of characters on the output. I was trying to take out pieces of hongp's code to see if I could get a freq value. Still garbage. I realized that the Serial.begin was different than the examples so I changed it too 9600, which is the usual. then your for loop and many other things I tried gave real numbers rather than strange characters.
115200 = no good for reading serial print ---- 9600 = readable serial print
doing a frequency test that goes through all of the audible frequencies through hongp's code pushes this.
37hz - 111hz - 148hz -185hz - 222hz - 259hz - 296hz - 333hz - 370hz - 407 hz - 444 hz - 481hz - 518hz - 555hz - 592hz -629hz - 666hz - 703hz - 740hz - 777hz - 814hz - 851hz - 888hz - 925hz - 962hz - 999 hz - 1036hz - 1073hz - 1110hz - 1147hz - 1184hz - 1221hz - 1221hz - 1258hz - 1295hz - 1369hz - 1406hz - 1480hz- 1517hz - 1554hz
until hitting 4699 and dropping back down. This probably has to do with his int resolution, removing this does not give good results.
I think I will need to spend a good amount of time learning FFT and how it works to really be able to get into this code. I was thinking that I was going to easily find frequencies with it, at least by simply going through a frequency test.
#define LOG_OUT 1 // use the log output function
#define FFT_N 256 // set to 256 point fft
#include <FFT.h> // include the library
//UNO clock Frequency = 16 MHz
//It takes 13 clock cycles to finish analog reading
int refFrequency = 0;
int currentFrequency = 0;
int previousFrequency = 0;
int errorFrequency = 0;
int refState = 0;
int currentState = 0;
int tunningState = 0;
boolean inRange = false;
float P = 0;
float I = 0.0;
float D = 0.0;
float drive = 0;
int pwmDrive = 0;
const int refInput = 8; //reference pin
const int currentInput = 9; //final pin
const int ForMotorControl = 10; //pump control pin PWM
const int BacMotorControl = 11; //pump control pin PWM
const int tunning = 12; //tuning control pin
int bin = 0;
int frequency = 0;
int resolution = 9615 / 256;
int maxLogOut = 0;
void setup() {
Serial.begin(9600); // use the serial port
pinMode(refInput, INPUT);
pinMode(currentInput, INPUT);
pinMode(tunning, INPUT);
pinMode(ForMotorControl, OUTPUT);
pinMode(BacMotorControl, OUTPUT);
ADCSRA |= (1<<ADPS2)|(1<<ADPS1)|(1<<ADPS0); //set adc prescaler=128
ADMUX = 0x40; // use adc0
ADCSRA |= (1<<ADATE); //enable auto trigger
ADCSRA |= (1<<ADEN); //enable ADC
ADCSRA |= (1<<ADSC); //start ADC measurements
}
void loop() {
while(1) { // reduces jitter
cli(); // UDRE interrupt slows this way down on arduino1.0
//sampling
for (int i = 0 ; i < 512 ; i += 2) { // save 256 samples
while(!(ADCSRA & 0x10)); // wait for adc to be ready
ADCSRA |=(1<<ADSC); //start ADC measurements
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
fft_input[i] = k; // put real data into even bins
fft_input[i+1] = 0; // set odd bins to 0
}//end of for
//FFT
fft_window(); // window the data for better frequency response
fft_reorder(); // reorder the data before doing the fft
fft_run(); // process the data in the fft
fft_mag_log(); // take the output of the fft
sei();
maxLogOut = 0;
for(int i = 1; i < 128; i++){
if(fft_log_out[i] > maxLogOut && fft_log_out[i] > 150){
maxLogOut = fft_log_out[i];
bin = i;
}//end of if
}//end of for
frequency = bin * resolution;
if(frequency > 1500 && frequency < 2700){
inRange = true;
} else {
inRange = false;
}
//if digital pin 8 is high, set the reference frequency
//if digital pin 9 is high, set the current frequency
//if digital pin 12 is high, set tunning state = high
refState = digitalRead(refInput);
currentState = digitalRead(currentInput);
tunningState = digitalRead(tunning);
if(refState == HIGH && inRange == true){
refFrequency = frequency;
} else if(currentState == HIGH && inRange == true){
currentFrequency = frequency;
} //end of else if
//error tracking
//highest frequency = (2405)2479 hz lowest frequency = (1517) 1628 hz
errorFrequency = refFrequency - currentFrequency;
P = errorFrequency; //proportional term
// I = Integral * 0; //intergral term
// D = (previousFrequency - currentFrequency) * 0; //derivative term
// previousFrequency = currentFrequency;
drive = P * (255.0/888.0); //scaleFactor = 255 * 888;
//start tuning if tunning state = high
if(tunningState == HIGH){
//motor control
if(errorFrequency > 30){ //pump liquid out
//digitalWrite(); //pump in one direction
digitalWrite(BacMotorControl, HIGH);
analogWrite(ForMotorControl, 0);
} else if (errorFrequency < -30){ //pump liquid in
//digitalWrite(); //pump in another direction
digitalWrite(BacMotorControl, LOW);
pwmDrive = (int)abs(drive);
if(pwmDrive < 80){ pwmDrive = pwmDrive + 80;}
analogWrite(ForMotorControl, pwmDrive);
} else { //stop pumping
analogWrite(ForMotorControl, 0); //stop the motor
digitalWrite(BacMotorControl, LOW);
}
} else {
analogWrite(ForMotorControl, 0); //stop the motor
digitalWrite(BacMotorControl, LOW);
}
//debug
Serial.print("frequency: ");
Serial.print(frequency);
Serial.print(" | ");
Serial.print("reference frequency: ");
Serial.print(refFrequency);
Serial.print(" | ");
Serial.print("Current frequency: ");
Serial.print(currentFrequency);
Serial.print(" | ");
Serial.print("error frequency: ");
Serial.println(errorFrequency);
}//end of while
}//end of loop
