Control An RC Car With A Smartphone

[tabby title=”Video Walkthrough”] Learn the basics of controlling objects with your Smartphone through Bluetooth!


[tabby title=”Parts List”]

Acquiring the Parts
Here’s what you will need:

TOTAL COST: ~$30.00

[tabby title=”Step 1″]

Adding Bluetooth to the Arduino

  1. To get started on adding bluetooth to the Arduino, you can watch my Arduino Bluetooth Basics Tutorial
  2. For a wiring diagram, you can reference my Fritzing sketch. (You need to download Fritzing
    in order t. view this.)

    h-bridge-wiring

[tabby title=”Step 2″]

Software

Android

  1. To find your bluetooth’s MAC address, a good program to use is called Ardudroid on the Google Play store.
  2. To control the car, Tolik777 has created a great app that you can download from here and install on your Anrdoid device.

Arduino

  1. The first thing you need to to is download the Arduino software for your computer.
  2. Then you need to copy this code to a new sketch and upload it to your Arduino device. Code provided by
 
#include "EEPROM.h"

#define D1 2          // direction of motor rotation 1
#define M1 3          // PWM left motor
#define D2 4          // direction of motor rotation 2
#define M2 5          // PWM right motor
#define HORN 13       // additional channel 1
//#define autoOFF 2500  // milliseconds after which the robot stops when the connection

#define cmdL 'L'      // UART-command for left motor
#define cmdR 'R'      // UART-command for right motor
#define cmdH 'H'      // UART-command for additional channel (for example Horn)
#define cmdF 'F'      // UART-command for EEPROM operation
#define cmdr 'r'      // UART-command for EEPROM operation (read)
#define cmdw 'w'      // UART-command for EEPROM operation (write)

char incomingByte;    // incoming data

char L_Data[4];       // array data for left motor
byte L_index = 0;     // index of array L
char R_Data[4];       // array data for right motor
byte R_index = 0;     // index of array R
char H_Data[1];       // array data for additional channel
byte H_index = 0;     // index of array H
char F_Data[8];       // array data for  EEPROM
byte F_index = 0;     // index of array F
char command;         // command

unsigned long currentTime, lastTimeCommand, autoOFF;

void setup() {
  Serial.begin(9600);       // initialization UART
  pinMode(HORN, OUTPUT);    // additional channel
  pinMode(D1, OUTPUT);      // output for motor rotation
  pinMode(D2, OUTPUT);      // output for motor rotation
  /*EEPROM.write(0,255);
  EEPROM.write(1,255);
  EEPROM.write(2,255);
  EEPROM.write(3,255);*/
  timer_init();             // initialization software timer
}

void timer_init() {
  uint8_t sw_autoOFF = EEPROM.read(0);   // read EEPROM "is activated or not stopping the car when losing connection"
  if(sw_autoOFF == '1'){                 // if activated
    char var_Data[3];
    var_Data[0] = EEPROM.read(1);
    var_Data[1] = EEPROM.read(2);
    var_Data[2] = EEPROM.read(3);
    autoOFF = atoi(var_Data)*100;        // variable autoOFF ms
  }
  else if(sw_autoOFF == '0'){        
    autoOFF = 999999;
  }
  else if(sw_autoOFF == 255){
    autoOFF = 2500;                      // if the EEPROM is blank, dafault value is 2.5 sec
  }
  currentTime = millis();                // read the time elapsed since application start
}
 
void loop() {
  if (Serial.available() > 0) {          // if received UART data
    incomingByte = Serial.read();        // raed byte
    if(incomingByte == cmdL) {           // if received data for left motor L
      command = cmdL;                    // current command
      memset(L_Data,0,sizeof(L_Data));   // clear array
      L_index = 0;                       // resetting array index
    }
    else if(incomingByte == cmdR) {      // if received data for left motor R
      command = cmdR;
      memset(R_Data,0,sizeof(R_Data));
      R_index = 0;
    }
    else if(incomingByte == cmdH) {      // if received data for additional channel
      command = cmdH;
      memset(H_Data,0,sizeof(H_Data));
      H_index = 0;
    }   
    else if(incomingByte == cmdF) {      // if received data for EEPROM op
      command = cmdF;
      memset(F_Data,0,sizeof(F_Data));
      F_index = 0;
    }
    else if(incomingByte == '\r') command = 'e';   // end of line
    else if(incomingByte == '\t') command = 't';   // end of line for EEPROM op
    
    if(command == cmdL && incomingByte != cmdL){
      L_Data[L_index] = incomingByte;              // store each byte in the array
      L_index++;                                   // increment array index
    }
    else if(command == cmdR && incomingByte != cmdR){
      R_Data[R_index] = incomingByte;
      R_index++;
    }
    else if(command == cmdH && incomingByte != cmdH){
      H_Data[H_index] = incomingByte;
      H_index++;
    }   
    else if(command == cmdF && incomingByte != cmdF){
      F_Data[F_index] = incomingByte;
      F_index++;
    }   
    else if(command == 'e'){                       // if we take the line end
      Control4WD(atoi(L_Data),atoi(R_Data),atoi(H_Data));
      delay(10);
    }
    else if(command == 't'){                       // if we take the EEPROM line end
      Flash_Op(F_Data[0],F_Data[1],F_Data[2],F_Data[3],F_Data[4]);
    }
    lastTimeCommand = millis();                    // read the time elapsed since application start
  }
  if(millis() >= (lastTimeCommand + autoOFF)){     // compare the current timer with variable lastTimeCommand + autoOFF
    Control4WD(0,0,0);                             // stop the car
  }
}

void Control4WD(int mLeft, int mRight, uint8_t Horn){

  bool directionL, directionR;      // direction of motor rotation L298N
  byte valueL, valueR;              // PWM M1, M2 (0-255)
  
  if(mLeft > 0){
    valueL = mLeft;
    directionL = 0;
  }
  else if(mLeft < 0){
    valueL = 255 - abs(mLeft);
    directionL = 1;
  }
  else {
    directionL = 0;
    valueL = 0;
  }
 
  if(mRight > 0){
    valueR = mRight;
    directionR = 0;
  }
  else if(mRight < 0){
    valueR = 255 - abs(mRight);
    directionR = 1;
  }
  else {
    directionR = 0;
    valueR = 0;
  }
   
  analogWrite(M1, valueL);            // set speed for left motor
  analogWrite(M2, valueR);            // set speed for right motor
  digitalWrite(D1, directionL);       // set direction of left motor rotation
  digitalWrite(D2, directionR);       // set direction of right motor rotation
  
  digitalWrite(HORN, Horn);           // additional channel
}

void Flash_Op(char FCMD, uint8_t z1, uint8_t z2, uint8_t z3, uint8_t z4){

  if(FCMD == cmdr){           // if EEPROM data read command
    Serial.print("FData:");       // send EEPROM data
    Serial.write(EEPROM.read(0));     // read value from the memory with 0 address and print it to UART
    Serial.write(EEPROM.read(1));
    Serial.write(EEPROM.read(2));
    Serial.write(EEPROM.read(3));
    Serial.print("\r\n");         // mark the end of the transmission of data EEPROM
  }
  else if(FCMD == cmdw){          // if EEPROM data write command
    EEPROM.write(0,z1);               // z1 record to a memory with 0 address
    EEPROM.write(1,z2);
    EEPROM.write(2,z3);
    EEPROM.write(3,z4);
    timer_init();             // reinitialize the timer
    Serial.print("FWOK\r\n");         // send a message that the data is successfully written to EEPROM
  }
}
[tabby title="Links"]

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Partner Project 13: Mobile Apps

In part 13 of the Partner Project, we discuss different options for making your website or Youtube channel mobile by showing you paid and free options for making mobile apps for your content.

For those interested in coding your own apps from scratch, here’s the links to the individual developer portals for each phone:

For Apple: http://developer.apple.com/ ($99)
For Windows Phone 7: http://create.msdn.com/en-US/ ($99)
And forJava Phones (which is essentially all dumb phones): http://www.oracle.com/technetwork/java/index-jsp-135888.html ($0)
And here’s the free App creator programs available:
AppInventor (Android): http://info.appinventor.mit.edu
Andromo (Android): http://www.andromo.com – splits add revenue with you 50/50
AppMakr (Android, iOS, WP7): http://www.appmakr.com
Conduit (All Smartphone Platforms): http://mobile.conduit.com – splits add revenue with you after your app becomes popular
If you’re using the app for a Youtube channel, here’s an extra tips to help you along:
To embed your Youtube Channel as an RSS feed, use this format:
feed://gdata.youtube.com/feeds/users/YOUR_CHANNEL/uploads
Where YOUR_CHANNEL is the name of your Youtube channel.

Partner Project 12: Domain Names

These are the highlights from my Live series “The Partner Project” which aired on Monday December 19th at 3:00pm. We discussed website domain names and the different options for attaining them.

Free Domain Names

* http://www.freedomain.co.nr

* http://co.cc/

Free Top Level Domains

* http://www.ezyfree.com/free-domain-name.php

* http://www.dot.tk/en/index.html?lang=en