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realtime clock sync; filename with timestamp (no overwrite of files);…
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… distance from noise floor as amplitude threshold; bins_with_signal as trigger for cars passing by
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Nanu Frechen committed Jan 12, 2024
1 parent e457bea commit 8187d8a
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4 changes: 2 additions & 2 deletions Teensy_prototype/FFT_visualisation/FFT_visualisation.pde
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Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,7 @@ String inString;
float oldpeak = 0;
int baseline;
PImage img;
int speed_cutoff = 10;
int speed_cutoff = 0;
int step;

int[] num = new int[512];
Expand Down Expand Up @@ -235,7 +235,7 @@ void draw () {
}else{
i = int(map(pixel, 0, img.height-1, max_speed/speed_conversion-1, 0));
}
float col = map(nums[i], -120, 1, 255, 0);
float col = map(nums[i], 4, 80, 255, 0);
img.pixels[pixel] = color(col,col,col);
}

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88 changes: 47 additions & 41 deletions Teensy_prototype/Teensy_prototype.ino
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,8 @@
#include <SerialFlash.h>
#include <utility/imxrt_hw.h>
#include <TimeLib.h>
#include "noise_floor.h"
#include "functions.h"

// Audio shield SD card:
#define SDCARD_CS_PIN 10
Expand All @@ -18,27 +20,9 @@
// #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
int n2 = 1 + (24000000 * 27) / (freq * 256 * n1);
double C = ((double)freq * 256 * n1 * n2) / 24000000;
int c0 = C;
int c2 = 10000;
int c1 = C * c2 - (c0 * c2);
set_audioClock(c0, c1, c2, true);
CCM_CS1CDR = (CCM_CS1CDR & ~(CCM_CS1CDR_SAI1_CLK_PRED_MASK | CCM_CS1CDR_SAI1_CLK_PODF_MASK))
| CCM_CS1CDR_SAI1_CLK_PRED(n1-1) // &0x07
| CCM_CS1CDR_SAI1_CLK_PODF(n2-1); // &0x3f
}

void printDigits(int digits){
// utility function for digital clock display: prints preceding colon and leading 0
SerialUSB1.print(":");
if(digits < 10)
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
Expand All @@ -51,8 +35,17 @@ bool write_sd = false;
const bool write_8bit = true;
const bool write_raw_data = true;
const bool write_csv_table = true;
float mean_amplitude_trigger_threshold;
float mean_amplitude_reverse_trigger_threshold = mean_amplitude_trigger_threshold;
float mean_amplitude_trigger_wait_time;
float noise_floor_distance_threshold = 8; //dB
uint8_t bins_with_signal;
uint8_t bins_with_signal_reverse;

//variables
char file_name_bin[30];
char file_name_csv[30];
float noise_floor_distance[1024];
uint16_t send_num_fft_bins; // is calculated from sen_max_speed
float max_amplitude; //highest signal in spectrum
uint16_t max_freq_Index;
Expand All @@ -77,8 +70,8 @@ unsigned long time_millis;
uint16_t file_version = 1;

// IQ calibration
float alpha = 0.9; //1.10;
float psi = 0.04; //-0.04;
float alpha = 1.10;
float psi = -0.04;
float A, C, D;

AudioAnalyzeFFT1024_IQ_F32 fft_IQ1024;
Expand All @@ -101,6 +94,7 @@ AudioConnection_F32 patchCord6(linein, 0, headphone, 0);
AudioConnection_F32 patchCord7(linein, 1, headphone, 1);

void setup() {
setSyncProvider(getTeensy3Time);
setI2SFreq(sample_rate);

// Audio connections require memory to work. For more
Expand Down Expand Up @@ -151,18 +145,14 @@ void setup() {
//timestamp = now();
timestamp = Teensy3Clock.get();
setTime(timestamp);
sprintf(file_name_bin, "rawdata_%0d-%0d-%0d_%0d-%0d-%0d.BIN", year(), month(), day(), hour(), minute(), second());
sprintf(file_name_csv, "metrics_%0d-%0d-%0d_%0d-%0d-%0d.csv", year(), month(), day(), hour(), minute(), second());

if (!(SD.begin(SDCARD_CS_PIN))) {
Serial.println("Unable to access the SD card");
}else{
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 = SD.open(file_name_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);
Expand All @@ -171,11 +161,8 @@ void setup() {
data_file.flush();
}
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, direction, strength, mean_amplitude, mean_amplitude_reverse, pedestrian_mean_amplitude");
csv_file = SD.open(file_name_csv, FILE_WRITE);
csv_file.println("timestamp, speed, direction, strength, mean_amplitude, mean_amplitude_reverse, bins_with_signal, bins_with_signal_reverse, pedestrian_mean_amplitude");
csv_file.flush();
}
write_sd = true;
Expand Down Expand Up @@ -269,23 +256,35 @@ void loop() {
mean_amplitude_reverse = 0.0;
pedestrian_amplitude = 0.0;
direction = 1;
bins_with_signal = 0;
bins_with_signal_reverse = 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 = 0; i < 1024; i++){
noise_floor_distance[i] = saveDat[i] - noise_floor[i];
}

for(i = (max_pedestrian_bin+1+iq_offset); i < send_max_fft_bin; i++) {
mean_amplitude = mean_amplitude + saveDat[i];
mean_amplitude_reverse = mean_amplitude_reverse + saveDat[1024-i];
if (max(saveDat[i], saveDat[1024-i]) > max_amplitude) {
max_amplitude = max(saveDat[i], saveDat[1024-i]); //remember highest amplitude
mean_amplitude = mean_amplitude + noise_floor_distance[i];
if(noise_floor_distance[i] > noise_floor_distance_threshold){
bins_with_signal++;
}
mean_amplitude_reverse = mean_amplitude_reverse + noise_floor_distance[1024-i];
if(noise_floor_distance[1024-i] > noise_floor_distance_threshold){
bins_with_signal_reverse++;
}
if (max(noise_floor_distance[i], noise_floor_distance[1024-i]) > max_amplitude) {
max_amplitude = max(noise_floor_distance[i], noise_floor_distance[1024-i]); //remember highest amplitude
max_freq_Index = i; //remember frequency index
}
}
if(iq_measurement){
if(saveDat[max_freq_Index] > saveDat[1024-max_freq_Index]){
if(noise_floor_distance[max_freq_Index] > noise_floor_distance[1024-max_freq_Index]){
direction = 1;
}else{
direction = -1;
Expand Down Expand Up @@ -327,6 +326,10 @@ void loop() {
csv_file.print(", ");
csv_file.print(mean_amplitude_reverse);
csv_file.print(", ");
csv_file.print(bins_with_signal);
csv_file.print(", ");
csv_file.print(bins_with_signal_reverse);
csv_file.print(", ");
csv_file.println(pedestrian_amplitude);
csv_file.flush();
}
Expand All @@ -350,12 +353,15 @@ void loop() {
// send spectrum
for(i = send_min_fft_bin; i < send_max_fft_bin; i++)
{
Serial.write((byte*)&saveDat[i], 4);
Serial.write((byte*)&noise_floor_distance[i], 4);
}

send_output = false;
}
}
}


time_t getTeensy3Time()
{
return Teensy3Clock.get();
}

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