if you want to know how to make a robot which can be control using android mobile via Bluetooth module then you are at right place .

Step 1: GET Components

1. old CD drive case
2. two small toy gear motor
3. Bluetooth module
4. Arduino uno
5. four tyre
6. motor driver circuit
7. some wires
8. small breed board for installing bluetooth module
9. 2 Dummy motor
10. 12v and 9v batteries
11. and at last a Android with Arduino Bluetooth Controller app installed in it.

TOOLS :-
1.hot melt glue stick
2.soldering iron and soldering wire
3.screwdriver (to open cd drive)
4.Drill machine -(optional)
5.double sided tape .

Step 2: First Make Cheap ROBOT CHASSIS

1. Take a old CD drive remove its all component and circuits and you will get strong aluminium box.
By using CD drive you have a advantage that we get small compartment for your components(best for war robots).

2. Join motor and dummy motor using hot glue gun and nuts you can easily make holes in aluminum using drill or screwdriver for nuts.

3.Insulate upper chassis using transparent tape . this is to prevent loss of current due to short circuit.

4. Paint chassis if you want

warning!!!!!!
dont hurt yourself while opening CD drive it is not easy to open it.

Step 3: Choose Good TYRES

Buy tyres with good rubber grip.
2 for motor and 2 for dummy motor.

remember toy gear motor and dummy motor need different tyre so dont buy all same tyre.

tyre of toy gear motor is also called hobby tyre and sometime they are sold with motor itself.

-> It is advisable not to buy metal gear motor as they need big hole and you may destroy your robot chassis while making hole as aluminium is tough metal .

Step 4: BATTERIES

Battery is heart of a robot .good batteries will give more power and more speed to your bot.

I brought 5 small 4v lead acid battery and some 9v battery connector

1. join 3 battery in series (4+4+4=12)
and 9 v battery connector to it
2. similarly join other 2 other batteries.(2+2=8)

8v for Arduino and 12v for robot.

WHY LEAD ACID BATTERIES ?

though they are big and heavy compared to lithium battery but they have many advantages

1. They can be charged from simple rectifier circuit so they don't need balance or special charger.

2.These batteries cost me 1$ each but if you use li-po or li-on it will cost you minimum 20$ and their charger for 15$.

3.safety!!!! lead acid are safe you can break them ,short circuit them, charge them on higher voltage but if you do some thing with li-x batteries then you will surly set your home in fire.

warning!!!!!
never short circuit your battery . heat can damage insulation of wire and you may also burn your fingers

Step 5: MOTOR DRIVER CIRCUIT

Arduino cannot power motor so we need motor driver circuit for amplification of signal from Arduino

you have 3 choice for this

1.buy readymade motor driver module (beginner)
2.make motor driver circuit using L293D ic on breadboard? (learners)
3.make your own motor driver circuit using L298N ic with heat sink. (expert)

if u buy cheap motor driver module remember that it can control only 2 motors

DIFFERENCE b//w L293D $ L298N

1. L298N cannot be used in breadboard but you can by bending its legs but not advisable. so you should be expert in making circuit.

2. L293d not made for high current that's why it has 4 ground pin to act as heat sink

3.L298n cost you double than L293d

i made my own using two L298N for with 4 output

HINT :-)

use 2 ic for 4 input and 4 output so that in future you can modify your robot.

Step 6: Burn Your PROGRAM. 囧

Burn your program in arduino uno

its program is simple but if you have any problem mail me anmolmamgain1@gmail.com

//copy paste this program
//
byte m1 = 2,m2 = 3,m11 = 4,m22 = 5;
char data;

void setup()
{ pinMode(9, OUTPUT);
digitalWrite(9, HIGH);
Serial.begin(9600);
pinMode(m1, OUTPUT); pinMode(m2, OUTPUT); pinMode(m11, OUTPUT); pinMode(m22, OUTPUT);
}

void loop()
{
if (Serial.available())
{ data = Serial.read(); }

if (data=='f')
{
digitalWrite(m1, HIGH);
digitalWrite(m11, HIGH);
delay(100);
}
else if (data=='b')
{
digitalWrite(m2, HIGH);
digitalWrite(m22, HIGH);
delay(100);
}
else if (data=='l')
{ digitalWrite(m2, HIGH);
digitalWrite(m11, HIGH);
delay(100);
}
else if (data=='r')
{ digitalWrite(m22, HIGH);
digitalWrite(m1, HIGH);
delay(100);
}

else
{
digitalWrite(m2, LOW);
digitalWrite(m1, LOW);
digitalWrite(m22, LOW);
digitalWrite(m11, LOW);
}

data = 'O';
}

Step 7: CONNECTIONS

connection should be made as per your program and remember you cant upload your program if Bluetooth module is attached with it so remove tx and rx wire before uploading program .

connect Arduino to motor driver as given below

Arduino | motor driver
Pin 2 | input 1
Pin 3 | input 2
Pin 4 | input 3
Pin 5 | input 4
+5 v to + 5v
ground to ground

connecting Bluetooth is also easy
connect it in small bread board
bt rx to Arduino tx
bt tx to Arduino rx
enable pin to pin 9
and +5v to Arduino +5v
and ground pin to Arduino ground

ATTENTION !!!!!
before connecting motor driver circuit check it using multimeter for back current as a single mistake can fry your Arduino.

if your motor driver circuit is readymade it has enable pin for speed control connect it with +5v as controlling speed is not needed in this project

Step 8: FINAL STEP. (if Bot Is Not Working Don't Check It Remake It)

this is final step check every thing twice place your robot on hard surface and follow step given below

1.power the Arduino and robot

2.Run ArduinoRC app in your phone pair it with Bluetooth module of bot your phone will ask password and password should be 1234

3.Now app will ask which mode ?
there are car mode, dimmer mode, controller mode and terminal mode.

4. chose terminal mode first and send command to move your bot as per your program.
if it is moving go to controller mode set command for forward button and similarly for all direction

eg.. if you program is
if(data==f)
{OUTPUT(m1,HIGH); OUTPUT(m2,HIGH); }

then send 'f ' to move it forward from terminal mode

and set forward button to 'f' in controller mode settings
similarly set these command in setting of controller mode.
f -> forward
b -> backward
l -> left
r -> right

Run your robot and have fun└(^o^)┘

Step 9: NOW WHAT TO DO SIR???? (?_?)

you can do many thing now.

1. Attach gripper to it.

2. Attach weapon to it and challenge your friend for bot war.

3. like my Facebook page "ROBO maker ".

4. modify it by attaching sensor to it you can put rf camera on it and become spy .

5.don't abuse me for my English as it is my second language