Hello everyone,
I'm very new to arduino etc etc, but I've decided to go ahead and Hack an old toy car. For the time being I would like to get this old toy car to work forwards and backwards via Bluetooth / Android Phone. The Bluetooth actually does what it's supposed to and drives the motor in both directions.
My problem is with the L293D. The motor runs at full speed when connected to the batteries directly (5.9V across the motor), but when connected to pins 3 & 6 of the L293D, it'll only run at approximately 1/2 the required speed (3.6V across the motor).
I have attached a photo of the circuit diagram for your perusal (sorry its hand written).
Also here is the code which I cannot take any credit for whatsoever 
Hope someone can help
/*
* created by Rui Santos, http://randomnerdtutorials.wordpress.com
* Control DC motor with Smartphone via bluetooth
* 2013
*/
int motorPin1 = 3; // pin 2 on L293D IC
int motorPin2 = 4; // pin 7 on L293D IC
int enablePin = 5; // pin 1 on L293D IC
int state;
int flag=0; //makes sure that the serial only prints once the state
void setup() {
// sets the pins as outputs:
pinMode(motorPin1, OUTPUT);
pinMode(motorPin2, OUTPUT);
pinMode(enablePin, OUTPUT);
// sets enablePin high so that motor can turn on:
digitalWrite(enablePin, HIGH);
// initialize serial communication at 9600 bits per second:
Serial.begin(9600);
}
void loop() {
//if some date is sent, reads it and saves in state
if(Serial.available() > 0){
state = Serial.read();
flag=0;
}
// if the state is '0' the DC motor will turn off
if (state == '0') {
digitalWrite(motorPin1, LOW); // set pin 2 on L293D low
digitalWrite(motorPin2, LOW); // set pin 7 on L293D low
if(flag == 0){
Serial.println("Motor: off");
flag=1;
}
}
// if the state is '1' the motor will turn right
else if (state == '1') {
digitalWrite(motorPin1, LOW); // set pin 2 on L293D low
digitalWrite(motorPin2, HIGH); // set pin 7 on L293D high
if(flag == 0){
Serial.println("Motor: right");
flag=1;
}
}
// if the state is '2' the motor will turn left
else if (state == '2') {
digitalWrite(motorPin1, HIGH); // set pin 2 on L293D high
digitalWrite(motorPin2, LOW); // set pin 7 on L293D low
if(flag == 0){
Serial.println("Motor: left");
flag=1;
}
}
}
