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store 8bit raw data
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Nanu Frechen committed Oct 29, 2023
1 parent 049149f commit 4f357ce
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Showing 3 changed files with 128 additions and 147 deletions.
1 change: 1 addition & 0 deletions Teensy_prototype/.gitignore
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*.autosave
2 changes: 1 addition & 1 deletion Teensy_prototype/FFT_visualisation/FFT_visualisation.pde
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Expand Up @@ -9,7 +9,7 @@ int speed = 0;
int oldspeed = 0;
int num_fft_bins;
float spec_speed = 0;
int sample_rate = 44100;
int sample_rate = 12000;
float fft_bin_width = sample_rate/1024;
float speed_conversion = fft_bin_width/44.0; //44100/1024/44; //1.578125;
float max_speed;
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272 changes: 126 additions & 146 deletions Teensy_prototype/Teensy_prototype.ino
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Expand Up @@ -8,8 +8,6 @@
#include <utility/imxrt_hw.h>
#include <TimeLib.h>



// Audio shield SD card:
#define SDCARD_CS_PIN 10
#define SDCARD_MOSI_PIN 7 // Teensy 4 ignores this, uses pin 11
Expand All @@ -20,7 +18,6 @@
// #define SDCARD_MOSI_PIN 11 // not actually used
// #define SDCARD_SCK_PIN 13 // not actually used


void setI2SFreq(int freq) {
// PLL between 27*24 = 648MHz und 54*24=1296MHz
int n1 = 4; //SAI prescaler 4 => (n1*n2) = multiple of 4
Expand All @@ -42,44 +39,40 @@ void printDigits(int digits){
SerialUSB1.print('0');
SerialUSB1.print(digits);
}

// configs:
const uint16_t sample_rate = 12000;
const uint8_t audio_input = AUDIO_INPUT_LINEIN; //AUDIO_INPUT_LINEIN or AUDIO_INPUT_MIC
const uint8_t linein_level = 15; //only relevant if AUDIO_INPUT_LINEIN is used
float mic_gain = 1.0; //only relevant if AUDIO_INPUT_MIC is used
const float max_pedestrian_speed = 10.0;
const bool iq_measurement = true;
float send_max_speed = 100;
bool write_sd = false;
const bool write_8bit = true;
const bool write_raw_data = true;
const bool write_csv_table = false;

//variables
uint16_t send_num_fft_bins; // is calculated from sen_max_speed
float max_amplitude; //highest signal in spectrum
uint16_t max_freq_Index;
float mean_amplitude;
float speed_conversion = (sample_rate/1024)/44.0;
float max_pedestrian_speed = 10.0;
float speed_conversion = (sample_rate/1024.0)/44.0;
uint16_t max_pedestrian_bin = int(max_pedestrian_speed/speed_conversion);
float pedestrian_amplitude;
uint16_t send_max_fft_bin = (uint16_t)min(512, int(send_max_speed/speed_conversion));
int input;
char command[1];
float mic_gain = 1.0;
float saveDat[1024];
bool send_output = false;
float peak;
bool iq_measurement = true;
uint16_t iq_offset;
uint16_t send_max_fft_bins = 1024;
uint16_t send_from;
uint16_t send_min_fft_bin;
File data_file;
File csv_file;
time_t timestamp;
bool send_output = false;
unsigned long time_millis;
uint16_t file_version = 1;
bool write_sd = false;
bool write_8bit = true;
int write_counter=0;
bool write_raw_data = true;
uint16_t discard_counter = 0;
uint16_t discard_after_write = 0;

uint16_t length_write_buffer = 1;
unsigned long timestamps[100];
float speeds[100];
float strengths[100];
float means_amplitude[100];
float means_pedestrian_amplitudes[100];


// IQ calibration
float alpha = 1.10;
Expand All @@ -88,23 +81,23 @@ float A, C, D;

AudioAnalyzeFFT1024_IQ_F32 fft_IQ1024;
AudioAnalyzePeak_F32 peak1;
AudioEffectGain_F32 gain0;
AudioEffectGain_F32 I_gain;
AudioMixer4_F32 Q_mixer;


AudioInputI2S_F32 linein;
AudioOutputI2S_F32 headphone;
AudioControlSGTL5000 sgtl5000_1;
AudioConnection_F32 patchCord1(linein, 1, gain0, 0);
AudioConnection_F32 patchCord2(gain0, 0, fft_IQ1024, 0); // I-channel
AudioConnection_F32 patchCord3(linein, 1, Q_mixer, 0); // I input
AudioConnection_F32 patchCord3b(linein, 0, Q_mixer, 1); // Q input
AudioConnection_F32 patchCord4(Q_mixer, 0, fft_IQ1024, 1); // Q-channel
AudioConnection_F32 patchCord1(linein, 0, I_gain, 0); // I_gain I input
AudioConnection_F32 patchCord2(I_gain, 0, fft_IQ1024, 0); // FFT I input

AudioConnection_F32 patchCord3(linein, 0, Q_mixer, 0); // Q-mixer I input
AudioConnection_F32 patchCord3b(linein, 1, Q_mixer, 1); // Q-mixer Q input
AudioConnection_F32 patchCord4(Q_mixer, 0, fft_IQ1024, 1); // FFT Q input

AudioConnection_F32 patchCord5(linein, 0, peak1, 0);
AudioConnection_F32 patchCord6(linein, 0, headphone, 0);
AudioConnection_F32 patchCord7(linein, 1, headphone, 1);


void setup() {
setI2SFreq(sample_rate);

Expand All @@ -114,11 +107,11 @@ void setup() {

// Enable the audio shield, select input, and enable output
sgtl5000_1.enable();
sgtl5000_1.inputSelect(AUDIO_INPUT_LINEIN); //AUDIO_INPUT_LINEIN or AUDIO_INPUT_MIC
sgtl5000_1.micGain(0); //only relevant if AUDIO_INPUT_MIC is used
sgtl5000_1.lineInLevel(15); //only relevant if AUDIO_INPUT_LINEIN is used
sgtl5000_1.inputSelect(audio_input); //AUDIO_INPUT_LINEIN or AUDIO_INPUT_MIC
sgtl5000_1.micGain(mic_gain); //only relevant if AUDIO_INPUT_MIC is used
sgtl5000_1.lineInLevel(linein_level); //only relevant if AUDIO_INPUT_LINEIN is used
sgtl5000_1.volume(.5);
gain0.setGain(1);
I_gain.setGain(1);

fft_IQ1024.windowFunction(AudioWindowHanning1024);
fft_IQ1024.setNAverage(1);
Expand All @@ -129,11 +122,15 @@ void setup() {
digitalWrite(PIN_A4, LOW);

if(iq_measurement){
send_from = 1024-send_max_fft_bins;
iq_offset = 512;
send_num_fft_bins = send_max_fft_bin * 2;
send_max_fft_bin = send_max_fft_bin+512;
send_min_fft_bin = (1024-send_max_fft_bin);

}else{
send_from = 0;
iq_offset = 0;
send_min_fft_bin = 0;
send_num_fft_bins = send_max_fft_bin;
}

//============== SD card =============
Expand All @@ -150,26 +147,29 @@ void setup() {
if (!(SD.begin(SDCARD_CS_PIN))) {
Serial.println("Unable to access the SD card");
}else{
if (SD.exists("RECORD.BIN")) {
// The SD library writes new data to the end of the
// file, so to start a new recording, the old file
// must be deleted before new data is written.
SD.remove("RECORD.BIN");
if(write_raw_data){
if (SD.exists("RECORD.BIN")) {
// The SD library writes new data to the end of the
// file, so to start a new recording, the old file
// must be deleted before new data is written.
SD.remove("RECORD.BIN");
}
data_file = SD.open("RECORD.BIN", FILE_WRITE);
data_file.write((byte*)&file_version, 2);
data_file.write((byte*)&timestamp, 4);
data_file.write((byte*)&send_num_fft_bins, 2);
data_file.write((byte*)&iq_measurement, 1);
data_file.write((byte*)&sample_rate, 2);
data_file.flush();
}
data_file = SD.open("RECORD.BIN", FILE_WRITE);
data_file.write((byte*)&file_version, 2);
data_file.write((byte*)&timestamp, 4);
data_file.write((byte*)&send_max_fft_bins, 2);
data_file.write((byte*)&iq_measurement, 1);
data_file.write((byte*)&sample_rate, 2);
data_file.flush();

if(SD.exists("detections.csv")){
SD.remove("detections.csv");
if(write_csv_table){
if(SD.exists("detections.csv")){
SD.remove("detections.csv");
}
csv_file = SD.open("detections.csv", FILE_WRITE);
csv_file.println("timestamp, speed, strength, mean_amplitude, pedestrian_mean_amplitude");
csv_file.flush();
}
csv_file = SD.open("detections.csv", FILE_WRITE);
csv_file.println("timestamp, speed, strength, mean_amplitude, pedestrian_mean_amplitude");
csv_file.flush();
write_sd = true;
}

Expand Down Expand Up @@ -214,10 +214,12 @@ void loop() {
SerialUSB1.println(alpha);
SerialUSB1.print("psi = ");
SerialUSB1.println(psi);

//after https://www.faculty.ece.vt.edu/swe/argus/iqbal.pdf
A = 1/alpha;
C = -sin(psi)/(alpha*cos(psi));
D = 1/cos(psi);
gain0.setGain(A);
I_gain.setGain(A);
Q_mixer.gain(0, C);
Q_mixer.gain(1, D);
}
Expand Down Expand Up @@ -249,106 +251,84 @@ void loop() {
uint32_t i;

if(fft_IQ1024.available()){
if(discard_counter > 0){
SerialUSB1.println("discard this");
discard_counter--;
}else{
float* pointer = fft_IQ1024.getData();
for (int kk=0; kk<1024; kk++) saveDat[kk]= *(pointer + kk);

// detect highest frequency
max_amplitude = -200.0;
max_freq_Index = 0;
mean_amplitude = 0.0;
pedestrian_amplitude = 0.0;

//detect pedestrian
for(i = 3+iq_offset; i < max_pedestrian_bin+iq_offset; i++){
pedestrian_amplitude = pedestrian_amplitude + saveDat[i];
}
pedestrian_amplitude = pedestrian_amplitude/max_pedestrian_bin;

for(i = (max_pedestrian_bin+1+iq_offset); i < send_max_fft_bins; i++) {
mean_amplitude = mean_amplitude + saveDat[i];
if (saveDat[i] > max_amplitude) {
max_amplitude = saveDat[i]; //remember highest amplitude
max_freq_Index = i; //remember frequency index
}
}
mean_amplitude = mean_amplitude/(send_max_fft_bins-(max_pedestrian_bin+1+iq_offset)); // TODO: is this valid when working with dB values?


timestamps[write_counter] = millis();
speeds[write_counter] = (max_freq_Index-iq_offset)*speed_conversion;
strengths[write_counter] = max_amplitude;
means_amplitude[write_counter] = mean_amplitude;
means_pedestrian_amplitudes[write_counter] = pedestrian_amplitude;

write_counter++;

if(write_counter >= length_write_buffer){
//write_sd = true;
write_counter = 0;
}else{
write_sd = false;
float* pointer = fft_IQ1024.getData();
for (int kk=0; kk<1024; kk++) saveDat[kk]= *(pointer + kk);

// detect highest frequency
max_amplitude = -200.0;
max_freq_Index = 0;
mean_amplitude = 0.0;
pedestrian_amplitude = 0.0;

//detect pedestrian
for(i = 3+iq_offset; i < max_pedestrian_bin+iq_offset; i++){
pedestrian_amplitude = pedestrian_amplitude + saveDat[i];
}
pedestrian_amplitude = pedestrian_amplitude/max_pedestrian_bin;

for(i = (max_pedestrian_bin+1+iq_offset); i < send_max_fft_bin; i++) {
mean_amplitude = mean_amplitude + saveDat[i];
if (saveDat[i] > max_amplitude) {
max_amplitude = saveDat[i]; //remember highest amplitude
max_freq_Index = i; //remember frequency index
}

// save data on sd card
if(write_sd){
time_millis = millis();
if(write_raw_data){
if(write_8bit){
data_file.write((byte*)&time_millis, 4);
for(i = 0; i < 1024; i++){
data_file.write((uint8_t)-saveDat[i]);
}
}else{
data_file.write((byte*)&time_millis, 4);
data_file.write((byte*)pointer, 1024*4);
}
mean_amplitude = mean_amplitude/(send_max_fft_bin-(max_pedestrian_bin+1+iq_offset)); // TODO: is this valid when working with dB values?

// save data on sd card
if(write_sd){
time_millis = millis();
if(write_raw_data){
if(write_8bit){
data_file.write((byte*)&time_millis, 4);
for(i = send_min_fft_bin; i < send_max_fft_bin; i++){
data_file.write((uint8_t)-saveDat[i]);
}
}else{
data_file.write((byte*)&time_millis, 4);
for(i = send_min_fft_bin; i < send_max_fft_bin; i++){
data_file.write((byte*)&saveDat[i], 4);
}
data_file.flush();
}

for(i = 0; i < length_write_buffer; i++){
//csv_file.println("timestamp, speed, strength, mean_amplitude, pedestrian_amplitude");
csv_file.print(timestamps[i]);
csv_file.print(", ");
csv_file.print(speeds[i]);
csv_file.print(", ");
csv_file.print(strengths[i]);
csv_file.print(", ");
csv_file.print(means_amplitude[i]);
csv_file.print(", ");
csv_file.println(means_pedestrian_amplitudes[i]);
}
data_file.flush();
}
if(write_csv_table){
//"timestamp, speed, strength, mean_amplitude, pedestrian_amplitude"
csv_file.print(time_millis);
csv_file.print(", ");
csv_file.print((max_freq_Index-iq_offset)*speed_conversion);
csv_file.print(", ");
csv_file.print(max_amplitude);
csv_file.print(", ");
csv_file.print(mean_amplitude);
csv_file.print(", ");
csv_file.println(pedestrian_amplitude);
csv_file.flush();
discard_counter = discard_after_write;

// SerialUSB1.print("csv sd write time: ");
// SerialUSB1.println(millis()-time_millis);
}

// send data via Serial
if(send_output){
Serial.write((byte*)&mic_gain, 1);
// SerialUSB1.print("csv sd write time: ");
// SerialUSB1.println(millis()-time_millis);
}


Serial.write((byte*)&max_freq_Index, 2);
// send data via Serial
if(Serial && send_output){
Serial.write((byte*)&mic_gain, 1);

peak = peak1.read();
Serial.write((byte*)&peak, 4);

Serial.write((byte*)&max_freq_Index, 2);

uint16_t number_send = send_max_fft_bins-send_from;
Serial.write((byte*)&(number_send), 2);
peak = peak1.read();
Serial.write((byte*)&peak, 4);

// send spectrum
for(i = send_from; i < send_max_fft_bins; i++)
{
Serial.write((byte*)&saveDat[i], 4);
}
Serial.write((byte*)&(send_num_fft_bins), 2);

send_output = false;
// send spectrum
for(i = send_min_fft_bin; i < send_max_fft_bin; i++)
{
Serial.write((byte*)&saveDat[i], 4);
}

send_output = false;
}
}
}
Expand Down

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