GPS + IMU Wio Terminal Logger

The device was gently shaken up and down and, in theory, there should be a sine shaped plot on the Y axis, but it's obviously corrupted:

The logger was put on the dashboard of my van in an attempt to detect pot holes.

GPS logging was pretty good and after messing about with some basic sample length = 60 filters, I got some coherent results for the IMU. Potholes should have been seen on the Y axis in the last two 'hillocks' of speed, but nothing was seen !! Maybe a better IMU is required with less noise and more G-Force capability?

#include <SoftwareSerial.h>
#include <TinyGPS.h>
#include <TFT_eSPI.h> // Graphics and font library for ILI9341 driver 
#include"LIS3DHTR.h"
#include "RTC_SAMD51.h"
#include "DateTime.h"
#include <SPI.h>
#include <SD.h>
#include <FlashStorage_SAMD.h>
#define FLASH_DEBUG       0
#define TFT_GREY  0x5AEB
#define YELLOW    0xFFE0
#define RED       0xF800
FlashStorage(my_flash_store, int);
TFT_eSPI tft = TFT_eSPI();  // Invoke library
LIS3DHTR<TwoWire> lis;
RTC_SAMD51 rtc;

int captureTime;
int SDWriteTime;
unsigned long avSDWriteTime =0;
int SDwriteCycleTime;
unsigned long start1;
unsigned long finish1;
unsigned long start2;
unsigned long finish2;
unsigned long currentMicros1;
unsigned long previousMicros1 =0;
unsigned long count2 = 0;
// string to buffer output
String buffer;
String filename;
unsigned long lastMillis = 0;
int stateOne = 0;
float flat = 0.00000000;
float flon = 0.00000000;
float GPSspeed = 0.0;
int GPSsatelites = 0;
int GPSprecision = 0;
int flashNumber;
uint16_t address = 0;

// File object to represent file
File txtFile;

/* This sample code demonstrates the normal use of a TinyGPS object.
   It requires the use of SoftwareSerial, and assumes that you have a
   9600-baud serial GPS device hooked up on pins D0(rx) and D1(tx) - the
   SIM28 Seed studio grove GPS module.
   
*/

TinyGPS gps;
SoftwareSerial ss(0, 1);

void setup()
{
 // Read the content of emulated-EEPROM
  EEPROM.get(address, flashNumber);
  // Save into emulated-EEPROM the number increased by 1 for the next run of the sketch
  EEPROM.put(address, (int) (flashNumber + 1));
  if (!EEPROM.getCommitASAP())
  {
    // Serial.println("CommitASAP not set. Need commit()");
    EEPROM.commit();
  }
  tft.init();
  tft.setRotation(2);
  tft.fillScreen(TFT_BLACK);
  tft.setCursor(0, 0, 2);
  tft.setTextColor(YELLOW, TFT_BLACK);  tft.setTextSize(2);
  tft.println(" GPS + G-Force ");
  tft.println("  Data Logger  ");
  tft.println("     V.1.01    ");
  tft.setTextColor(TFT_WHITE, TFT_BLACK);  tft.setTextSize(2);
 
  Serial.begin(115200);
  // while(!Serial){1;};
  // tft.println("Serial started ...");
  delay(5000);
  ss.begin(9600);
  lis.begin(Wire1);
  rtc.begin();
  
  DateTime now = DateTime(F(__DATE__), F(__TIME__));
  Serial.println("adjust time!");
  rtc.adjust(now);

  // yyyy/MM/dd HH:mm:ss
  // SD file name is restricted to 8 characters !!
  // filename += now.year(); filename += "";
  // filename += now.month(); filename += "";
  filename += now.day(); filename += "";
  filename += now.hour(); filename += "_";
  // Use a flash stored variable to ensure unique filename:
  filename += String(flashNumber);
  filename += ".txt";

  if (!lis) 
  {
    Serial.println("ERROR");
    while(1);
  }
  lis.setOutputDataRate(LIS3DHTR_DATARATE_50HZ); //Data output rate
  lis.setFullScaleRange(LIS3DHTR_RANGE_2G); //Scale range set to 2g

  // reserve 1kB for String used as a buffer
  buffer.reserve(2048);

  // set LED pin to output, used to blink when writing
  pinMode(LED_BUILTIN, OUTPUT);

  // init the SD card
  if (!SD.begin()) 
  {
    tft.setTextColor(RED, TFT_BLACK);  tft.setTextSize(2);
    tft.println("  No SD card?  ");
    Serial.println("Card failed, or not present");
    // don't do anything more:
    while (1);
  }

  // If you want to start from an empty file,
  // uncomment the next line:
  // SD.remove(filename);

  // try to open the file for writing
  txtFile = SD.open(filename, FILE_WRITE);
  if (!txtFile) 
  {
    Serial.print("error opening ");
    Serial.println(filename);
    while (1);
  }

  txtFile.write("Millis,Timestamp,Accel_X,Accel_Y,Accel_Z,Satelites,Speed(km/h),Latitude,Longitude,GPSprecision \r\n");
  
  Serial.print("Simple TinyGPS library v. "); Serial.println(TinyGPS::library_version());
  Serial.println("by Mikal Hart");
  Serial.println();
}

void loop()
{
  bool newData = false;
  unsigned long chars;
  unsigned short sentences, failed;

  // For one second we parse GPS data and report some key values
  for (unsigned long currentMillis = millis(); millis() - currentMillis < 1000;)
  {
    while (ss.available())
    {
      start1 = micros();
      char c = ss.read();
      Serial.write(c); // uncomment this line if you want to see the GPS data flowing
      if (gps.encode(c)) // Did a new valid sentence come in?
        newData = true;
      finish1 = micros();
    }
    captureTime = finish1 - start1;

    float x_values, y_values, z_values;
    x_values = lis.getAccelerationX();
    y_values = lis.getAccelerationY();
    z_values = lis.getAccelerationZ();

//////////////////////////////////////////////////////////////////

    // check if it's been over 20 ms since the last line added
    unsigned long currentMillisTwo = millis();
    if ((currentMillisTwo - lastMillis) >= 20)
    {
      DateTime now = rtc.now();
      // Serial.println("Write to the buffer !!");
      // add a new line to the buffer
      buffer += currentMillisTwo; buffer += ",";

      // yyyy/MM/dd HH:mm:ss
      buffer += now.year(); buffer += "-";
      buffer += now.month(); buffer += "-";
      buffer += now.day(); buffer += " ";
      buffer += now.hour(); buffer += ":"; 
      buffer += now.minute(); buffer += ":"; 
      buffer += now.second(); buffer += ",";

      buffer += String(x_values,3); buffer += ",";
      buffer += String(y_values,3); buffer += ",";
      buffer += String(z_values,3); buffer += ",";
      GPSsatelites = gps.satellites();
      if (GPSsatelites == 255)
      {
        GPSsatelites = 0;
      }
      buffer += String(GPSsatelites); buffer += ",";
      GPSspeed = gps.f_speed_kmph();
      if (GPSspeed < 0)
      {
        GPSspeed = 0.0;
      }
      buffer += String(GPSspeed,3); buffer += ",";
      buffer += String(flat,8); buffer += ",";
      buffer += String(flon,8); buffer += ",";
      GPSprecision = gps.hdop();
      if (GPSprecision < 0)
      {
        GPSprecision = 0;
      }
      buffer += String(GPSprecision);
      buffer += "\r\n";
      // Serial.println(flat);
      // Serial.println(buffer);
      lastMillis = currentMillisTwo;
    }

    // check if the SD card is available to write data without blocking
    // and if the buffered data is enough for the full chunk size
    unsigned int chunkSize = txtFile.availableForWrite();
    // Serial.print("chunkSize: "); Serial.print(chunkSize);
    // Serial.print("  buffer.length(): "); Serial.println(buffer.length());
    

    if (chunkSize && buffer.length() >= chunkSize)
    {
      currentMicros1 = micros();
      SDwriteCycleTime = currentMicros1 - previousMicros1;
      previousMicros1 = currentMicros1;
      if (stateOne == 0)
      {
        stateOne = 1;
        digitalWrite(LED_BUILTIN, HIGH);
      }
      else
      {
        stateOne = 0;
        digitalWrite(LED_BUILTIN, LOW);
      }
      // Serial.println("Write the buffer to the SD card !!");
      start2 = micros();
      txtFile.write(buffer.c_str(), chunkSize);
      finish2 = micros();
      SDWriteTime = finish2 - start2;
      
      // Initialise the averaging calc:
      if (avSDWriteTime == 0)
      {
        avSDWriteTime = SDWriteTime;
      }
      // Apply arbitary averaging weights:
      avSDWriteTime = (avSDWriteTime*49 + SDWriteTime)/50;
      
      // remove written data from buffer
      buffer.remove(0, chunkSize);
    }
///////////////////////////////////////////////////////////
  }

  if (newData)
  {
    unsigned long age;
    gps.f_get_position(&flat, &flon, &age);
    Serial.print("LAT=");
    Serial.print(flat == TinyGPS::GPS_INVALID_F_ANGLE ? 0.0 : flat, 6);
    Serial.print(" LON=");
    Serial.print(flon == TinyGPS::GPS_INVALID_F_ANGLE ? 0.0 : flon, 6);
    Serial.print(" SAT=");
    Serial.print(gps.satellites() == TinyGPS::GPS_INVALID_SATELLITES ? 0 : gps.satellites());
    Serial.print(" PREC=");
    Serial.print(gps.hdop() == TinyGPS::GPS_INVALID_HDOP ? 0 : gps.hdop());

    tft.fillScreen(TFT_BLACK);
    tft.setCursor(0, 0, 2);
    tft.print("LAT= ");tft.println(flat == TinyGPS::GPS_INVALID_F_ANGLE ? 0.0 : flat, 6);
    tft.print("LON= ");tft.println(flon == TinyGPS::GPS_INVALID_F_ANGLE ? 0.0 : flon, 6);
    tft.print("SATS= ");tft.println(gps.satellites() == TinyGPS::GPS_INVALID_SATELLITES ? 0 : gps.satellites());
    tft.print("PREC= ");tft.println(gps.hdop() == TinyGPS::GPS_INVALID_HDOP ? 0 : gps.hdop());
    // tft.print("SPEED= ");tft.println(gps.f_speed_kmph(), TinyGPS::GPS_INVALID_F_SPEED, 6, 2);
    tft.print("SPEED= ");tft.println(gps.f_speed_kmph() == TinyGPS::GPS_INVALID_F_SPEED ? 0.0 : gps.f_speed_kmph());
    tft.print("CAPT= ");tft.print(captureTime);tft.println(" uS");
    tft.print("SDWr= ");tft.print(SDWriteTime);tft.println(" uS");
    tft.print("aSDW= ");tft.print(avSDWriteTime);tft.println(" uS");
    tft.print("SDWc= ");tft.print(SDwriteCycleTime);tft.println(" uS");
    tft.print("FName= ");tft.print(filename);
    
  }
  else
  {
    tft.fillScreen(TFT_BLACK);
    tft.setCursor(0, 0, 2);
    tft.println("No GPS fix");
    tft.print("CAPT= ");tft.println(captureTime);
  }
  
  gps.stats(&chars, &sentences, &failed);
  Serial.print(" CHARS=");
  Serial.print(chars);
  Serial.print(" SENTENCES=");
  Serial.print(sentences);
  Serial.print(" CSUM ERR=");
  Serial.println(failed);
  if (chars == 0)
    Serial.println("** No characters received from GPS: check wiring **");
}

#include <SoftwareSerial.h>
#include <TinyGPS.h>
#include <TFT_eSPI.h> // Graphics and font library for ILI9341 driver 
#include"LIS3DHTR.h"
#include "RTC_SAMD51.h"
#include "DateTime.h"
#include <SPI.h>
#include <SD.h>
#define TFT_GREY  0x5AEB
#define YELLOW    0xFFE0
#define RED       0xF800
TFT_eSPI tft = TFT_eSPI();  // Invoke library
LIS3DHTR<TwoWire> lis;
RTC_SAMD51 rtc;

int captureTime;
unsigned long start;
unsigned long finish;
// string to buffer output
String buffer;
String filename;
unsigned long lastMillis = 0;
int stateOne = 0;
float flat = 0.00000000;
float flon = 0.00000000;
float GPSspeed = 0.0;
int GPSsatelites = 0;
int GPSprecision = 0;

// File object to represent file
File txtFile;

/* This sample code demonstrates the normal use of a TinyGPS object.
   It requires the use of SoftwareSerial, and assumes that you have a
   9600-baud serial GPS device hooked up on pins D0(rx) and D1(tx).
*/

TinyGPS gps;
SoftwareSerial ss(0, 1);

void setup()
{
  tft.init();
  tft.setRotation(2);
  tft.fillScreen(TFT_BLACK);
  tft.setCursor(0, 0, 2);
  tft.setTextColor(YELLOW, TFT_BLACK);  tft.setTextSize(2);
  tft.println(" GPS + G-Force ");
  tft.println("  Data Logger  ");
  tft.println("     V.1.01    ");
  tft.setTextColor(TFT_WHITE, TFT_BLACK);  tft.setTextSize(2);
 
  Serial.begin(115200);
  // while(!Serial){1;};
  // tft.println("Serial started ...");
  delay(5000);
  ss.begin(9600);
  lis.begin(Wire1);
  rtc.begin();
  
  DateTime now = DateTime(F(__DATE__), F(__TIME__));
  Serial.println("adjust time!");
  rtc.adjust(now);

  // yyyy/MM/dd HH:mm:ss
  // SD file name is restricted to 8 characters !!
  // filename += now.year(); filename += "";
  // filename += now.month(); filename += "";
  filename += now.day(); filename += "";
  filename += now.hour(); filename += "";
  filename += now.minute(); filename += "";
  filename += now.second();
  filename += ".txt";

  if (!lis) 
  {
    Serial.println("ERROR");
    while(1);
  }
  lis.setOutputDataRate(LIS3DHTR_DATARATE_50HZ); //Data output rate
  lis.setFullScaleRange(LIS3DHTR_RANGE_2G); //Scale range set to 2g

  // reserve 1kB for String used as a buffer
  buffer.reserve(2048);

  // set LED pin to output, used to blink when writing
  pinMode(LED_BUILTIN, OUTPUT);

  // init the SD card
  if (!SD.begin()) 
  {
    tft.setTextColor(RED, TFT_BLACK);  tft.setTextSize(2);
    tft.println("  No SD card?  ");
    Serial.println("Card failed, or not present");
    // don't do anything more:
    while (1);
  }

  // If you want to start from an empty file,
  // uncomment the next line:
  // SD.remove(filename);

  // try to open the file for writing
  txtFile = SD.open(filename, FILE_WRITE);
  if (!txtFile) 
  {
    Serial.print("error opening ");
    Serial.println(filename);
    while (1);
  }

  txtFile.write("Millis,Timestamp,Accel_X,Accel_Y,Accel_Z,Satelites,Speed(km/h),Latitude,Longitude,GPSprecision \r\n");
  
  Serial.print("Simple TinyGPS library v. "); Serial.println(TinyGPS::library_version());
  Serial.println("by Mikal Hart");
  Serial.println();
}

void loop()
{
  bool newData = false;
  unsigned long chars;
  unsigned short sentences, failed;

  // For one second we parse GPS data and report some key values
  for (unsigned long currentMillis = millis(); millis() - currentMillis < 1000;)
  {
    while (ss.available())
    {
      start = micros();
      char c = ss.read();
      Serial.write(c); // uncomment this line if you want to see the GPS data flowing
      if (gps.encode(c)) // Did a new valid sentence come in?
        newData = true;
      finish = micros();
    }
    captureTime = finish - start;

    float x_values, y_values, z_values;
    x_values = lis.getAccelerationX();
    y_values = lis.getAccelerationY();
    z_values = lis.getAccelerationZ();

//////////////////////////////////////////////////////////////////

    // check if it's been over 20 ms since the last line added
    unsigned long currentMillisTwo = millis();
    if ((currentMillisTwo - lastMillis) >= 20)
    {
      DateTime now = rtc.now();
      // Serial.println("Write to the buffer !!");
      // add a new line to the buffer
      buffer += currentMillisTwo; buffer += ",";

      // yyyy/MM/dd HH:mm:ss
      buffer += now.year(); buffer += "-";
      buffer += now.month(); buffer += "-";
      buffer += now.day(); buffer += " ";
      buffer += now.hour(); buffer += ":"; 
      buffer += now.minute(); buffer += ":"; 
      buffer += now.second(); buffer += ",";

      buffer += String(x_values,3); buffer += ",";
      buffer += String(y_values,3); buffer += ",";
      buffer += String(z_values,3); buffer += ",";
      GPSsatelites = gps.satellites();
      if (GPSsatelites == 255)
      {
        GPSsatelites = 0;
      }
      buffer += String(GPSsatelites); buffer += ",";
      GPSspeed = gps.f_speed_kmph();
      if (GPSspeed < 0)
      {
        GPSspeed = 0.0;
      }
      buffer += String(GPSspeed,3); buffer += ",";
      buffer += String(flat,8); buffer += ",";
      buffer += String(flon,8); buffer += ",";
      GPSprecision = gps.hdop();
      if (GPSprecision < 0)
      {
        GPSprecision = 0;
      }
      buffer += String(GPSprecision);
      buffer += "\r\n";
      // Serial.println(flat);
      // Serial.println(buffer);
      lastMillis = currentMillisTwo;
    }

    // check if the SD card is available to write data without blocking
    // and if the buffered data is enough for the full chunk size
    unsigned int chunkSize = txtFile.availableForWrite();
    // Serial.print("chunkSize: "); Serial.print(chunkSize);
    // Serial.print("  buffer.length(): "); Serial.println(buffer.length());
    

    if (chunkSize && buffer.length() >= chunkSize)
    {
      if (stateOne == 0)
      {
        stateOne = 1;
        digitalWrite(LED_BUILTIN, HIGH);
      }
      else
      {
        stateOne = 0;
        digitalWrite(LED_BUILTIN, LOW);
      }
      // Serial.println("Write the buffer to the SD card !!");
      txtFile.write(buffer.c_str(), chunkSize);

      // remove written data from buffer
      buffer.remove(0, chunkSize);
    }
///////////////////////////////////////////////////////////
    
  }

  if (newData)
  {
    unsigned long age;
    gps.f_get_position(&flat, &flon, &age);
    Serial.print("LAT=");
    Serial.print(flat == TinyGPS::GPS_INVALID_F_ANGLE ? 0.0 : flat, 6);
    Serial.print(" LON=");
    Serial.print(flon == TinyGPS::GPS_INVALID_F_ANGLE ? 0.0 : flon, 6);
    Serial.print(" SAT=");
    Serial.print(gps.satellites() == TinyGPS::GPS_INVALID_SATELLITES ? 0 : gps.satellites());
    Serial.print(" PREC=");
    Serial.print(gps.hdop() == TinyGPS::GPS_INVALID_HDOP ? 0 : gps.hdop());

    tft.fillScreen(TFT_BLACK);
    tft.setCursor(0, 0, 2);
    tft.print("LAT= ");tft.println(flat == TinyGPS::GPS_INVALID_F_ANGLE ? 0.0 : flat, 6);
    tft.print("LON= ");tft.println(flon == TinyGPS::GPS_INVALID_F_ANGLE ? 0.0 : flon, 6);
    tft.print("SATS= ");tft.println(gps.satellites() == TinyGPS::GPS_INVALID_SATELLITES ? 0 : gps.satellites());
    tft.print("PREC= ");tft.println(gps.hdop() == TinyGPS::GPS_INVALID_HDOP ? 0 : gps.hdop());
    // tft.print("SPEED= ");tft.println(gps.f_speed_kmph(), TinyGPS::GPS_INVALID_F_SPEED, 6, 2);
    tft.print("SPEED= ");tft.println(gps.f_speed_kmph() == TinyGPS::GPS_INVALID_F_SPEED ? 0.0 : gps.f_speed_kmph());
    tft.print("CAPT= ");tft.print(captureTime);tft.println(" usecs");
  }
  else
  {
    tft.fillScreen(TFT_BLACK);
    tft.setCursor(0, 0, 2);
    tft.println("No GPS fix");
    tft.print("CAPT= ");tft.println(captureTime);
  }
  
  gps.stats(&chars, &sentences, &failed);
  Serial.print(" CHARS=");
  Serial.print(chars);
  Serial.print(" SENTENCES=");
  Serial.print(sentences);
  Serial.print(" CSUM ERR=");
  Serial.println(failed);
  if (chars == 0)
    Serial.println("** No characters received from GPS: check wiring **");
}