Tag: RC Car

ProfileBlock™ – DIY Robot Platform – Design Concepts

[ Upload design concept 20170418]

ProfileBlock – DIY Robots & Rover & RC & Etc. Platform

3D Design Tool: SketchUp Pro

ProfileBlock’s robots are built on top of an open source Arduino-based(with ESP8266, Raspberry Pi) platform.

    • drawBot: Drawing Robot (Polargraph, Pen, …
    • Rover

Self Balancing Robot (eX-Robot, B-Robot, Roverbot, …

Hardware

Base Plate(Parts):

  • Profile DF 2020
  • Profile DRF 2020
  • Acrylic Plate
  • 3D Printing Parts

Step Motor:

  • NEMA 17 – Phase: 4, Step Angle: 1.8 Deg/Step, Holding Torque: 2.6Kg.cm
  • 28BYJ-48

Servo:

  • Standard Servo
  • SG90 Servo

Electrical

Control Board:

  • Arduino
  • ESP8266
  • Raspberry Pi

Power Requirements:

  • 4.2DVC
  • 8.4VDC
  • 12 VDC

Battery:

  • 18650 x 2ea
  • 16340 x 2ea

The open source ProfileBlock hardware and software is free and made with love. Please show your level of support with a voluntary donation.

Donate:
https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=RDN7ZGAVFS5UE

Wii 리모컨(Wiimote)으로 RC Car 조종하기 – 2WS (Tamiya M-03)

이젠 벽돌이 되어버린 니텐도 Wii를 되살리기 차원에서 Wii 리모컨을 사용하여 RC Car를 조종하는 프로젝트를 시작해봅니다.

Source를 수정하여 Tamiya M-03 샤시에 적용해 보기로 했습니다.

Circuit@Home에서 소개 받았습니다!

RC car controlled by Wii Remote on Arduino http://www.circuitsathome.com/mcu/rc-car-controlled-by-wii-remote-on-arduino

USB Host를 적용하여 Bluetooth로 직접 연결하는 방식이기 때문에 구성은 매우 간단합니다.

Arduino는 Nano를 사용하였고 USB Host Shield와 연결하기 위해 Mother Board를 하나 꾸며보았습니다.

기능도 조금 추가했습니다.

바나나를 던지거나 하지는 못하지만 “A” 버튼을 누르면 레이저가 발사되듯이 Fire LED가 켜지도록 하였고 “+” 버튼은 Head Light, “-” 버튼은 Back Light로 사용할 수 있도록 하였습니다.

그리고 좌우방향 버튼으로도 Steering이 가능하도록 하였습니다.

 Arrow Up  Left steering
 Arrow Down  Right steering
 Arrow Left  Gear Down
 Arrow Right  Gear Up
 A  Fire & Shutting
 B  –
 +  Head Light
 –  Back Light
 1  Backward
 2  Forward
 Home  Throttle mode change

하드웨어 (Hardware)

송신기 (Transmitter)

  • Wii 리모컨 (Wiimote)

수신기 (Reciver)

  • Arduino Nano

  • USB Host Shield
  • Bluetooth USB 어댑터 (Dongle)

  • DIY Mother Board
 
 

통신 거리는 Bluetooth 특성상 대략 10m 정도 밖에 안될 거라고 예상합니다만 그 이상도 충분합니다.

 

RC Car

  • Tamiya M-03

소프트웨어 (Software)

Arduino 용 라이브러리와 스케치를 포함한 파일은 github 에 있습니다.
이 라이브러리는 Richard Ibbotson이 만든 코드 wiiblue.pde 을 기반으로하고 있습니다.

샘플 스케치 (Sketch)

TwoWheelSterringWii.ino

#include “WiiRemote.h”

#include <MemoryFree.h>

#include <Servo.h>

#define PIN_STEERING_SIGNAL        2

#define PIN_ESC_SIGNAL             4

#define PIN_HEAD_LIGHT_SIGNAL     14

#define PIN_BACK_LIGHT_SIGNAL     15

#define PIN_FIRE_SIGNAL           17

#define PIN_STEERING_SELECT       16

#define SERIAL_DEBUG               0    // 0: active mode, 1: serial debug mode

enum eAngle

{

STEERING_ANGLE_MAX           = 165,   // to right

STEERING_ANGLE_CENTER        = 90,

STEERING_ANGLE_MIN           = 15,    // to left

STEERING_ANGLE_STEP          = 5,

STEERING_ANGLE_MAX_INVERT    = 165,   // to right

STEERING_ANGLE_CENTER_INVERT = 90,

STEERING_ANGLE_MIN_INVERT    = 15,    // to left

THROTTLE_ANGLE_MAX           = 160,   // 80,

THROTTLE_ANGLE_CENTER        = 90,

THROTTLE_ANGLE_MIN           = 10,

};

enum eServoPulse

{

SERVO_PULSE_MAX              = 2400,  // to left

SERVO_PULSE_NEUTRAL          = 1550,  // 1500 Futaba compatible, 1.55msec

SERVO_PULSE_MIN              = 600,   // to right

SERVO_PULSE_MAX_INVERT       = 600,   // to right

SERVO_PULSE_NEUTRAL_INVERT   = 1450,  // 1460 Futaba compatible, 1.55msec

SERVO_PULSE_MIN_INVERT       = 2400,  // to left

};

enum eESCPulse

{

/*

*  Futaba timing

*

*  0us     1072us         1522us          1922us

*   +———*————+-*-+————-*

*   |   n/a   |   forwad   |d|d|   Reverse   |

*   +———*————+-*-+————-*

*          Max Forwad     Neutral         Max Reverse

*

*   d: dead zone, +10us and -10us

*/

ESC_PULSE_NEUTRAL     = 1522,

ESC_PULSE_BRAKE       = 1600,

ESC_PULSE_FWD_MAX     = 800,   //1200, // 1072

ESC_PULSE_FWD_MIN     = 1510,

ESC_PULSE_FWD_3RD     = (ESC_PULSE_FWD_MIN – 240),

ESC_PULSE_FWD_2ND     = (ESC_PULSE_FWD_MIN – 160),

ESC_PULSE_FWD_1ST     = (ESC_PULSE_FWD_MIN – 80),

ESC_PULSE_REV_MAX     = 1700,  // 1922

ESC_PULSE_REV_FIX     = 1650,

ESC_PULSE_REV_MIN     = 1600,

};

enum eGear

{

GEAR_1ST = 1,

GEAR_2ND = 2,

GEAR_3RD = 3,

};

WiiRemote wiiremote;

Servo SteeringServo;

Servo ESC;

void setup()

{

#if SERIAL_DEBUG

Serial.begin(115200);

Serial.print(“\r\nfreeMemory() reports: “);

Serial.print(freeMemory(), DEC);

Serial.println(“Serial connect…”);

#endif

SteeringServo.attach(PIN_STEERING_SIGNAL);

SteeringServo.writeMicroseconds(SERVO_PULSE_NEUTRAL);

ESC.attach(PIN_ESC_SIGNAL);

ESC.writeMicroseconds(ESC_PULSE_NEUTRAL);

pinMode(PIN_HEAD_LIGHT_SIGNAL, OUTPUT);

pinMode(PIN_BACK_LIGHT_SIGNAL, OUTPUT);

digitalWrite(PIN_HEAD_LIGHT_SIGNAL, LOW);

digitalWrite(PIN_BACK_LIGHT_SIGNAL, LOW);

pinMode(PIN_FIRE_SIGNAL, OUTPUT);

digitalWrite(PIN_FIRE_SIGNAL, LOW);

pinMode(PIN_STEERING_SELECT, INPUT);

digitalWrite(PIN_STEERING_SELECT, LOW);

wiiremote.init();

/*

unsigned char wiiremote_bdaddr[6] = {0x00, 0x1e, 0x35, 0xda, 0x48, 0xbc};

wiiremote.setBDAddress(wiiremote_bdaddr, 6);

wiiremote.setBDAddressMode(BD_ADDR_FIXED);

*/

#if SERIAL_DEBUG

Serial.println(“Wiimote connecting…”);

Serial.println(“Please press 1 button and 2 button simultaneously”);

#endif

}

void loop()

{

wiiremote.task(&myapp);

}

int steering_angle          = STEERING_ANGLE_CENTER;

int steering_angle_invert   = STEERING_ANGLE_CENTER_INVERT;

int old_steering_angle      = STEERING_ANGLE_CENTER;

bool analog_throttle        = false;  // false = use “One” button as throttle

int throttle_angle          = THROTTLE_ANGLE_CENTER;

int gear                    = GEAR_1ST;

int pulse_steering;

int pulse_esc;

bool fire                   = false;                  // fire

bool head_light             = false;                  // head light

bool back_light             = false;                  // back light

void myapp(void)

{

#if SERIAL_DEBUG

Serial.print(“\r\n”);

#endif

/* Steering */

steering_angle = getSteeringAngle();

steering_angle_invert = getSteeringAngleInvert();

if (digitalRead(PIN_STEERING_SELECT) == HIGH) {

pulse_steering = map(steering_angle,

STEERING_ANGLE_MIN, STEERING_ANGLE_MAX,

SERVO_PULSE_MAX, SERVO_PULSE_MIN);

SteeringServo.writeMicroseconds(pulse_steering);

} else {

pulse_steering = map(steering_angle_invert,

STEERING_ANGLE_MIN_INVERT, STEERING_ANGLE_MAX_INVERT,

SERVO_PULSE_MAX_INVERT, SERVO_PULSE_MIN_INVERT);

SteeringServo.writeMicroseconds(pulse_steering);

}

if (wiiremote.buttonPressed(WIIREMOTE_UP)) {

steering_angle = STEERING_ANGLE_MIN;

steering_angle_invert = STEERING_ANGLE_MIN_INVERT;

if (digitalRead(PIN_STEERING_SELECT) == HIGH) {

pulse_steering = map(steering_angle, STEERING_ANGLE_MIN, STEERING_ANGLE_MAX, SERVO_PULSE_MAX, SERVO_PULSE_MIN);

SteeringServo.writeMicroseconds(pulse_steering);

} else {

pulse_steering = map(steering_angle_invert, STEERING_ANGLE_MIN_INVERT, STEERING_ANGLE_MAX_INVERT, SERVO_PULSE_MAX_INVERT, SERVO_PULSE_MIN_INVERT);

SteeringServo.writeMicroseconds(pulse_steering);

}

} else if (wiiremote.buttonPressed(WIIREMOTE_DOWN)) {

steering_angle = STEERING_ANGLE_MAX;

steering_angle_invert = STEERING_ANGLE_MAX_INVERT;

if (digitalRead(PIN_STEERING_SELECT) == HIGH) {

pulse_steering = map(steering_angle, STEERING_ANGLE_MIN, STEERING_ANGLE_MAX, SERVO_PULSE_MAX, SERVO_PULSE_MIN);

SteeringServo.writeMicroseconds(pulse_steering);

} else {

pulse_steering = map(steering_angle_invert, STEERING_ANGLE_MIN_INVERT, STEERING_ANGLE_MAX_INVERT, SERVO_PULSE_MAX_INVERT, SERVO_PULSE_MIN_INVERT);

SteeringServo.writeMicroseconds(pulse_steering);

}

}

#if SERIAL_DEBUG

Serial.print(“\tServo=”);

Serial.print(pulse_steering);

#endif

/* Brake and Throttle */

if (wiiremote.buttonPressed(WIIREMOTE_ONE)) {

if (pulse_esc < ESC_PULSE_NEUTRAL) {

// moving forward before press “One”

brake();

pulse_esc = ESC_PULSE_NEUTRAL;

} else {

// while stopping or moving backward, keep moving backward

pulse_esc = ESC_PULSE_REV_FIX;

}

} else {

if (analog_throttle) {

throttle_angle = getThrottleAngle();

pulse_esc = map(throttle_angle,

THROTTLE_ANGLE_MIN, THROTTLE_ANGLE_MAX,

ESC_PULSE_FWD_MIN, ESC_PULSE_FWD_MAX);

} else if (wiiremote.buttonPressed(WIIREMOTE_TWO)) {

switch (gear) {

case GEAR_1ST:

pulse_esc = ESC_PULSE_FWD_1ST;

break;

case GEAR_2ND:

pulse_esc = ESC_PULSE_FWD_2ND;

break;

case GEAR_3RD:

pulse_esc = ESC_PULSE_FWD_3RD;

break;

default:

pulse_esc = ESC_PULSE_NEUTRAL;

break;

}

} else {

pulse_esc = ESC_PULSE_NEUTRAL;

}

}

ESC.writeMicroseconds(pulse_esc);

//delay(15);

#if SERIAL_DEBUG

Serial.print(“\tESC=”);

Serial.print(pulse_esc);

#endif

/* Throttle mode */

if (wiiremote.buttonClicked(WIIREMOTE_HOME)) {

analog_throttle = !analog_throttle;

if (analog_throttle) {

wiiremote.setLED(WIIREMOTE_LED4); // analog mode

} else {

wiiremote.setLED(WIIREMOTE_LED1); // fixed mode, 1st gear

gear = GEAR_1ST;

}

}

/* Shift up or down */

if (!analog_throttle) {

if (wiiremote.buttonClicked(WIIREMOTE_RIGHT)) {

shiftUp();

} else if (wiiremote.buttonClicked(WIIREMOTE_LEFT)) {

shiftDown();

}

}

/* Fire */

if (wiiremote.buttonPressed(WIIREMOTE_A)) {

digitalWrite(PIN_FIRE_SIGNAL, HIGH);

} else {

digitalWrite(PIN_FIRE_SIGNAL, LOW);

}

/* Head light LED */

if (wiiremote.buttonClicked(WIIREMOTE_PLUS)) {

head_light = !head_light;

if (head_light) {

digitalWrite(PIN_HEAD_LIGHT_SIGNAL, HIGH);

} else {

digitalWrite(PIN_HEAD_LIGHT_SIGNAL, LOW);

}

}

/* Back light LED */

if (wiiremote.buttonClicked(WIIREMOTE_MINUS)) {

back_light = !back_light;

if (back_light) {

digitalWrite(PIN_BACK_LIGHT_SIGNAL, HIGH);

} else {

digitalWrite(PIN_BACK_LIGHT_SIGNAL, LOW);

}

}

} // myapp

int getSteeringAngle(void)

{

double rad;

int deg;

rad = acos((double) wiiremote.Report.Accel.Y);

deg = (int) (rad * 180.0 / PI);

/* clipping */

if (deg > STEERING_ANGLE_MAX) { deg = STEERING_ANGLE_MAX; }

if (deg < STEERING_ANGLE_MIN) { deg = STEERING_ANGLE_MIN; }

return deg;

}

int getSteeringAngleInvert(void)

{

double rad;

int deg;

rad = acos((double) wiiremote.Report.Accel.Y);

deg = (int) (rad * 180.0 / PI);

/* clipping */

if (deg > STEERING_ANGLE_MAX_INVERT) { deg = STEERING_ANGLE_MAX_INVERT; }

if (deg < STEERING_ANGLE_MIN_INVERT) { deg = STEERING_ANGLE_MIN_INVERT; }

return deg;

}

int getThrottleAngle(void)

{

double rad;

double compensate_z;

int deg;

rad = asin((double) wiiremote.Report.Accel.Y);

compensate_z = (double) wiiremote.Report.Accel.Z / cos(rad);

rad = asin(compensate_z);

deg = (int) (rad * 180.0 / PI);

/* clipping */

if (deg > THROTTLE_ANGLE_MAX) { deg = THROTTLE_ANGLE_MAX; }

if (deg < THROTTLE_ANGLE_MIN) { deg = THROTTLE_ANGLE_MIN; }

return deg;

}

inline void brake(void)

{

ESC.writeMicroseconds(ESC_PULSE_BRAKE);

delay(15);

ESC.writeMicroseconds(ESC_PULSE_NEUTRAL);

delay(15);

}

inline void shiftUp(void)

{

if (gear < GEAR_3RD) {

gear++;

wiiremote.setLED( (WIIREMOTE_LED1 << (gear – GEAR_1ST)) );

}

}

inline void shiftDown(void)

{

if (gear > GEAR_1ST) {

gear–;

wiiremote.setLED( (WIIREMOTE_LED1 << (gear – GEAR_1ST)) );

}

}

Wii 리모컨(Wiimote)으로 RC Car 조종하기

이젠 벽돌이 되어버린 니텐도 Wii를 바라보다 갑자기 아깝다는 생각이 들어 폭풍 검색을 하다가 Wii 리모컨을 활용할 수 있는 괜찮은 소스를 찾은 것 같아 아래와 같이 소개 합니다.

잘~ 응용하면 재밋는 장난감이 되겠네요.

Circuit@Home에서 소개 받았습니다!

RC car controlled by Wii Remote on Arduino http://www.circuitsathome.com/mcu/rc-car-controlled-by-wii-remote-on-arduino

곳곳에서 Wii 리모컨을 사용한 재미있는 프로젝트를 볼 수 있습니다. PC에서 Bluetooth Stack를 이용한 프로젝트는 많은 있지만, PC를 사용하지 않고 마이컴 (AVR, PIC)에서 Bluetooth Stack를 이용한 프로젝트는 적은 것 같습니다. 그래서 (새삼 느낌입니다 만…) 마리오 카트를 조종하는 느낌으로 무선조종을 만들어 보았습니다. #바나나를 던지거나 하지는 않습니다.

하드웨어 (Hardware)

Arduino에서 Bluetooth Stack을 실현하여 무선조종서보와 ESC를 제어합니다.

송신기 (Transmitter)

  • Wii 리모컨 (Wiimote)

수신기 (Reciver)

  • Arduino
  • USB Host Shield
  • Bluetooth USB 어댑터 (Dongle)

통신 거리는 Bluetooth 특성상 대략 10m 정도 밖에 안될 거라고 예상합니다. 통신 거리를 늘리려면 XBee 등을 사용해야 할 것 입니다.

소프트웨어 (Software)

Arduino 용 라이브러리는 github 에 있습니다.
이 라이브러리는 Richard Ibbotson이 만든 코드 wiiblue.pde 을 기반으로하고 있습니다.
또한 이 라이브러리를 사용하기 위해서는, Oleg Mazurov가 개발 한 라이브러리 가 필요합니다.

샘플 스케치 (Sketch)

 

SterringWii.ino

#include "WiiRemote.h"
#include <MemoryFree.h>
#include <Servo.h>
#define PIN_STEERING_SIGNAL 2
#define PIN_ESC_SIGNAL  3
#define SERIAL_DEBUG 0
enum eAngle {
  STEERING_ANGLE_MAX    = 165,  // to right
  STEERING_ANGLE_MIN    = 15,   // to left
  STEERING_ANGLE_CENTER = 90,
  STEERING_ANGLE_STEP   = 5,
  THROTTLE_ANGLE_MAX    = 80,
  THROTTLE_ANGLE_MIN    = 10,
  THROTTLE_ANGLE_CENTER = 90,
};
enum eServoPulse {
  SERVO_PULSE_NEUTRAL = 1500, // Futaba compatible, 1.55msec
  SERVO_PULSE_MAX     = 1800, // to left
  SERVO_PULSE_MIN     = 1200, // to right
};
enum eESCPulse {
/*
 *  Futaba timing
 *
 *  0us     1072us         1522us          1922us
 *   +---------*------------+-*-+-------------*
 *   |   n/a   |   forwad   |d|d|   Reverse   |
 *   +---------*------------+-*-+-------------*
 *          Max Forwad     Neutral         Max Reverse
 *
 *   d: dead zone, +10us and -10us
 */
  ESC_PULSE_NEUTRAL = 1522,
  ESC_PULSE_BRAKE   = 1600,
  ESC_PULSE_FWD_MAX = 1200, // 1072
  ESC_PULSE_FWD_MIN = 1510,
  ESC_PULSE_FWD_3RD = (ESC_PULSE_FWD_MIN - 200),
  ESC_PULSE_FWD_2ND = (ESC_PULSE_FWD_MIN - 140),
  ESC_PULSE_FWD_1ST = (ESC_PULSE_FWD_MIN - 80),
  ESC_PULSE_REV_FIX = 1650,
  ESC_PULSE_REV_MAX = 1700, // 1922
  ESC_PULSE_REV_MIN = 1600,
};
enum eGear {
  GEAR_1ST = 1,
  GEAR_2ND = 2,
  GEAR_3RD = 3,
};
WiiRemote wiiremote;
Servo SteeringServo;
Servo ESC;
void setup()
{
#if SERIAL_DEBUG
  Serial.begin(9600);
  Serial.print("\r\nfreeMemory() reports: ");
  Serial.print(freeMemory(), DEC);
#endif
  SteeringServo.attach(PIN_STEERING_SIGNAL);
  SteeringServo.writeMicroseconds(SERVO_PULSE_NEUTRAL);
  ESC.attach(PIN_ESC_SIGNAL);
  ESC.writeMicroseconds(ESC_PULSE_NEUTRAL);
  wiiremote.init();
  /*
  unsigned char wiiremote_bdaddr[6] = {0x00, 0x1e, 0x35, 0xda, 0x48, 0xbc};
  wiiremote.setBDAddress(wiiremote_bdaddr, 6);
  wiiremote.setBDAddressMode(BD_ADDR_FIXED);
  */
}
void loop()
{
  wiiremote.task(&myapp);
}
int steering_angle = STEERING_ANGLE_CENTER;
int old_steering_angle = STEERING_ANGLE_CENTER;
bool analog_throttle = false;  // false = use "One" button as throttle
int throttle_angle = THROTTLE_ANGLE_CENTER;
int gear = GEAR_1ST;
int pulse_steering;
int pulse_esc;
void myapp(void) {
#if SERIAL_DEBUG
  Serial.print("\r\n");
#endif
  /* Steering */
  steering_angle = getSteeringAngle();
  pulse_steering = map(steering_angle,
                       STEERING_ANGLE_MIN, STEERING_ANGLE_MAX,
                       SERVO_PULSE_MAX, SERVO_PULSE_MIN);
  SteeringServo.writeMicroseconds(pulse_steering);
  //delay(15);
  Serial.print("\tServo=");
  Serial.print(pulse_steering);
  /* Brake and Throttle */
  if (wiiremote.buttonPressed(WIIREMOTE_ONE)) {
    if (pulse_esc < ESC_PULSE_NEUTRAL) {
      // moving forward before press "One"
      brake();
      pulse_esc = ESC_PULSE_NEUTRAL;
    } else {
      // while stopping or moving backward, keep moving backward
      pulse_esc = ESC_PULSE_REV_FIX;
    }
  } else {
    if (analog_throttle) {
      throttle_angle = getThrottleAngle();
      pulse_esc = map(throttle_angle,
                      THROTTLE_ANGLE_MIN, THROTTLE_ANGLE_MAX,
                      ESC_PULSE_FWD_MIN, ESC_PULSE_FWD_MAX);
    } else if (wiiremote.buttonPressed(WIIREMOTE_TWO)) {
      switch (gear) {
       case GEAR_1ST:
        pulse_esc = ESC_PULSE_FWD_1ST;
        break;
       case GEAR_2ND:
        pulse_esc = ESC_PULSE_FWD_2ND;
        break;
       case GEAR_3RD:
        pulse_esc = ESC_PULSE_FWD_3RD;
        break;
       default:
        pulse_esc = ESC_PULSE_NEUTRAL;
        break;
      }
    } else {
      pulse_esc = ESC_PULSE_NEUTRAL;
    }
  }
  ESC.writeMicroseconds(pulse_esc);
  //delay(15);
  Serial.print("\tESC=");
  Serial.print(pulse_esc);
  /* Throttle mode */
  if (wiiremote.buttonClicked(WIIREMOTE_A)) {
    analog_throttle = !analog_throttle;
    if (analog_throttle) {
      wiiremote.setLED(WIIREMOTE_LED4); // analog mode
    } else {
      wiiremote.setLED(WIIREMOTE_LED1); // fixed mode, 1st gear
      gear = GEAR_1ST;
    }
  }
  /* Shift up or down */
  if (!analog_throttle) {
    if (wiiremote.buttonClicked(WIIREMOTE_RIGHT)) {
      shiftUp();
    } else if (wiiremote.buttonClicked(WIIREMOTE_LEFT)) {
      shiftDown();
    }
  }
} // myapp
int getSteeringAngle(void) {
  double rad;
  int deg;
  rad = acos((double) wiiremote.Report.Accel.Y);
  deg = (int) (rad * 180.0 / PI);
  /* clipping */
  if (deg > STEERING_ANGLE_MAX) { deg = STEERING_ANGLE_MAX; }
  if (deg < STEERING_ANGLE_MIN) { deg = STEERING_ANGLE_MIN; }
  return deg;
}
int getThrottleAngle(void) {
  double rad;
  double compensate_z;
  int deg;
    rad = asin((double) wiiremote.Report.Accel.Y);
    compensate_z = (double) wiiremote.Report.Accel.Z / cos(rad);
    rad = asin(compensate_z);
    deg = (int) (rad * 180.0 / PI);
  /* clipping */
  if (deg > THROTTLE_ANGLE_MAX) { deg = THROTTLE_ANGLE_MAX; }
  if (deg < THROTTLE_ANGLE_MIN) { deg = THROTTLE_ANGLE_MIN; }
  return deg;
}
inline void brake(void)
{
    ESC.writeMicroseconds(ESC_PULSE_BRAKE);
    delay(15);
    ESC.writeMicroseconds(ESC_PULSE_NEUTRAL);
    delay(15);
}
inline void shiftUp(void)
{
    if (gear < GEAR_3RD) {
        gear++;
        wiiremote.setLED( (WIIREMOTE_LED1 << (gear - GEAR_1ST)) );
    }
}
inline void shiftDown(void)
{
    if (gear > GEAR_1ST) {
        gear--;
        wiiremote.setLED( (WIIREMOTE_LED1 << (gear - GEAR_1ST)) );
    }
}