TinyScreen / Accel

#define BLACK           0x00
#define BLUE            0xE0
#define RED             0x03
#define GREEN           0x1C
#define DGREEN           0x0C
#define YELLOW          0x1F
#define WHITE           0xFF
#define ALPHA           0xFE
#define BROWN           0x32

#include "SSD1331.h"
#include "BMA250.h"
#include <SPI.h>
#include <Wire.h>
#include <SD.h>

SSD1331 display = SSD1331(0);
BMA250 accel;
const int chipSelect = 10;

int x,y,z  = 0;
long count, time, delta = 0;
uint8_t back = BLACK;

void setup(void) {
  Serial.begin(9600); while (!Serial) { ; /*  wait for serial port to connect. */ }
  Wire.begin();

  // Init accelerator
  accel.begin(BMA250_range_2g, BMA250_update_time_64ms); //This sets up the BMA250 accelerometer

  // Init display
  display.begin();

  // Init SD Card
  Serial.print("Initializing SD card...");
  pinMode(10, OUTPUT);

  // see if the card is present and can be initialized:
  if (!SD.begin(chipSelect)) {
    Serial.println("Card failed, or not present"); return; // don't do anything more:
  }
  Serial.println("card initialized.");
}

void loop() {
  accel.read(); // Retrieve accelerometer data
  display.setFont(liberationSans_12ptFontInfo);

  int math = abs(accel.X - x) + abs(accel.Y - y) + abs(accel.Z - z);
  if (math > 50){
    x = accel.X;  y = accel.Y;  z = accel.Z;
    count = 0;
  }

  if (count++ > 4){
    writeSD(delta, time); time = 0;
    back = BLACK;
    display.clearWindow(0,0,96,64);
  } else {
    time++;
    back = RED;
    display.drawRect(0,0,96,64,1,back);
  }

  display.setCursor(0,10);
  display.fontColor(BLUE,back);
  display.print("X = "+ String(accel.X) + " / " + String(x));

  display.setCursor(0,25);
  display.fontColor(YELLOW,back);
  display.print("Y = "+ String(accel.Y) + " / " + String(y));

  display.setCursor(0,40);
  display.fontColor(GREEN,back);
  display.print("Z = "+ String(accel.Z) + " / " + String(z));

  // Serial.print("  Temperature(C) = ");
  // Serial.println((accel.rawTemp*0.5)+24.0,1);
  delta++;
  delay(250); // Retrieve accelerometer data more than 64ms update time set on the BMA250
}

void writeSD(long delta, long time){
  if (time == 0) return;
  File dataFile = SD.open("datalog.json", FILE_WRITE);
  String str = "{ \"delta\": " + String(delta*250/1000) + ", \"duration\":" + String(time*250/1000) + "}";
  dataFile.println(str);
  dataFile.close();
  Serial.println(str);

  if (SD.exists("datalog.json")) {
    Serial.println("datalog.json exists.");
  }
}