Arduino Code

#include <Adafruit_LSM303_Accel.h>
#include <Adafruit_Sensor.h>
#include <Wire.h>

const int motor1pin1 = 4;             // motor 1 forwards
const int motor1pin2 = 5;             // motor 1 backwards

const int motor2pin1 = 6;             // motor 2 forwards
const int motor2pin2 = 7;             // motor 2 backwards

/* Assign a unique ID to this sensor at the same time */
Adafruit_LSM303_Accel_Unified accel = Adafruit_LSM303_Accel_Unified(54321);

void setup() {
#ifndef ESP8266
  while (!Serial)
    ; // will pause Zero, Leonardo, etc until serial console opens
#endif
  Serial.begin(9600);
  Serial.println("Accelerometer Test");
  Serial.println("");

  /* Initialise the sensor */
  if (!accel.begin()) {
    /* There was a problem detecting the ADXL345 ... check your connections */
    Serial.println("Ooops, no LSM303 detected ... Check your wiring!");
    while (1)
      ;
  }

  accel.setRange(LSM303_RANGE_4G);
  Serial.print("Range set to: ");
  lsm303_accel_range_t new_range = accel.getRange();
  switch (new_range) {
  case LSM303_RANGE_2G:
    Serial.println("+- 2G");
    break;
  case LSM303_RANGE_4G:
    Serial.println("+- 4G");
    break;
  case LSM303_RANGE_8G:
    Serial.println("+- 8G");
    break;
  case LSM303_RANGE_16G:
    Serial.println("+- 16G");
    break;
  }

  accel.setMode(LSM303_MODE_NORMAL);
  Serial.print("Mode set to: ");
  lsm303_accel_mode_t new_mode = accel.getMode();
  switch (new_mode) {
  case LSM303_MODE_NORMAL:
    Serial.println("Normal");
    break;
  case LSM303_MODE_LOW_POWER:
    Serial.println("Low Power");
    break;
  case LSM303_MODE_HIGH_RESOLUTION:
    Serial.println("High Resolution");
    break;
  }

  pinMode(motor1pin1, OUTPUT);
  pinMode(motor1pin2, OUTPUT);
  pinMode(motor2pin1, OUTPUT);
  pinMode(motor2pin2, OUTPUT);
}

void loop() {
  /* Get a new sensor event */
  sensors_event_t event;
  accel.getEvent(&event);

  /* Display the results (acceleration is measured in m/s^2) */
  double currX = event.acceleration.x, currY = event.acceleration.y;
  int angleX = (map (event.acceleration.x, -9.8, 9.8, -70, 70)), angleY = (map (event.acceleration.y, -9.8, 9.8, -70, 70));
  Serial.print("X:");
  Serial.print(angleX);
  Serial.print(" ");
  Serial.print("Y:");
  Serial.print(angleY);
  Serial.print(" ");
  Serial.println("degrees");

  int speed1 = map(abs(angleX), 0, 70, 120, 255), speed2 = map(abs(angleY), 0, 70, 120, 255);

  if (angleX > 0) {
    digitalWrite(motor2pin1, HIGH);
    digitalWrite(motor1pin1, HIGH);
    digitalWrite(motor1pin2, 0);
    digitalWrite(motor2pin2, 0);
  } else if (angleX == 0) {
    digitalWrite(motor2pin1, 0);
    digitalWrite(motor1pin1, 0);
  }  else {
    digitalWrite(motor2pin2, HIGH);
    digitalWrite(motor1pin2, HIGH);
    digitalWrite(motor1pin1, 0);
    digitalWrite(motor2pin1, 0);
  }

  if (angleY > 0) {
    digitalWrite(motor1pin1, HIGH);
    digitalWrite(motor2pin2, HIGH);
    digitalWrite(motor2pin1, 0);
    digitalWrite(motor1pin2, 0);
  } else if (angleY == 0) {
    digitalWrite(motor1pin1, 0);
    digitalWrite(motor2pin2, 0);
  }  else {
    digitalWrite(motor1pin2, HIGH);
    digitalWrite(motor2pin1, HIGH);
    digitalWrite(motor2pin2, 0);
    digitalWrite(motor1pin1, 0);
  }

  /* Delay before the next sample */
  delay(500);
}