Published © GPL3+

F1 in Schools Car - Safety Modulation

Programming Adafruit Feather 32u4 to write acceleration and gyroscopic variables onto an SD card.

IntermediateWork in progress384
F1 in Schools Car - Safety Modulation

Things used in this project

Hardware components

Arduino UNO & Genuino UNO
Arduino UNO & Genuino UNO

Software apps and online services

Arduino IDE
Arduino IDE

Hand tools and fabrication machines



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The code, if u couldnt get it before



The code for the accelerometer and gyroscope
// (c) Michael Schoeffler 2017,
#include "Wire.h" // This library allows you to communicate with I2C devices.
#include <SPI.h>
#include <SD.h>
const int MPU_ADDR = 0x68; // I2C address of the MPU-6050. If AD0 pin is set to HIGH, the I2C address will be 0x69.
int16_t accelerometer_x, accelerometer_y, accelerometer_z; // variables for accelerometer raw data
int16_t gyro_x, gyro_y, gyro_z; // variables for gyro raw data
int16_t temperature; // variables for temperature data
char tmp_str[7]; // temporary variable used in convert function
char* convert_int16_to_str(int16_t i) { // converts int16 to string. Moreover, resulting strings will have the same length in the debug monitor.
sprintf(tmp_str, "%6d", i);
return tmp_str;
const int chipSelect = 4;
void setup() {
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port only

Serial.print("Initializing SD card...");

// see if the card is present and can be initialized:
if (!SD.begin(4)) {
Serial.println("Card failed, or not present");
// don't do anything more:
while (1);
Serial.println("card initialized.");
Wire.beginTransmission(MPU_ADDR); // Begins a transmission to the I2C slave (GY-521 board)
Wire.write(0x6B); // PWR_MGMT_1 register
Wire.write(0); // set to zero (wakes up the MPU-6050)

void loop() {
// make a string for assembling the data to log:
String dataString = "";

// read three sensors and append to the string:
for (int analogPin = 0; analogPin < 3; analogPin++) {
int sensor = analogRead(analogPin);
dataString += String(sensor);
if (analogPin < 2) {
dataString += ",";

// open the file. note that only one file can be open at a time,
// so you have to close this one before opening another.
File dataFile ="datalog.txt", FILE_WRITE);

// if the file is available, write to it:
if (dataFile) {
// print to the serial port too:
// if the file isn't open, pop up an error:
else {
Serial.println("error opening datalog.txt");
Wire.write(0x3B); // starting with register 0x3B (ACCEL_XOUT_H) [MPU-6000 and MPU-6050 Register Map and Descriptions Revision 4.2, p.40]
Wire.endTransmission(false); // the parameter indicates that the Arduino will send a restart. As a result, the connection is kept active.
Wire.requestFrom(MPU_ADDR, 7*2, true); // request a total of 7*2=14 registers

// "<<8 |;" means two registers are read and stored in the same variable
accelerometer_x =<<8 |; // reading registers: 0x3B (ACCEL_XOUT_H) and 0x3C (ACCEL_XOUT_L)
accelerometer_y =<<8 |; // reading registers: 0x3D (ACCEL_YOUT_H) and 0x3E (ACCEL_YOUT_L)
accelerometer_z =<<8 |; // reading registers: 0x3F (ACCEL_ZOUT_H) and 0x40 (ACCEL_ZOUT_L)
temperature =<<8 |; // reading registers: 0x41 (TEMP_OUT_H) and 0x42 (TEMP_OUT_L)
gyro_x =<<8 |; // reading registers: 0x43 (GYRO_XOUT_H) and 0x44 (GYRO_XOUT_L)
gyro_y =<<8 |; // reading registers: 0x45 (GYRO_YOUT_H) and 0x46 (GYRO_YOUT_L)
gyro_z =<<8 |; // reading registers: 0x47 (GYRO_ZOUT_H) and 0x48 (GYRO_ZOUT_L)

// print out data
Serial.print("aX = "); Serial.print(convert_int16_to_str(accelerometer_x));
Serial.print(" | aY = "); Serial.print(convert_int16_to_str(accelerometer_y));
Serial.print(" | aZ = "); Serial.print(convert_int16_to_str(accelerometer_z));
// the following equation was taken from the documentation [MPU-6000/MPU-6050 Register Map and Description, p.30]
Serial.print(" | tmp = "); Serial.print(temperature/340.00+36.53);
Serial.print(" | gX = "); Serial.print(convert_int16_to_str(gyro_x));
Serial.print(" | gY = "); Serial.print(convert_int16_to_str(gyro_y));
Serial.print(" | gZ = "); Serial.print(convert_int16_to_str(gyro_z));

// delay




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