In this project we show that how we control the movement of any small robot with the help of sensors. We will use thermistor for detecting fire .
Our project is to be divided into few parts.
- Automatic Vehicle
- Fountain sprayer
- LDR circuit for fire detection
CONCEPT:
In this project we use smart logic and control system of embedded system by using microcontroller. In this project we use ic 89S52 as a main processor.. microcontroller sense the signal and drive the motor of the robotic vehicle. .
will use LDR circuit for fire detection. We are using this sensor because we want to implement this concept in godown point of view.
We will use transistorized signal conditioning circuit for detection of signal from LDR sensor. After detection circuit we will give signal to microcontroller 89s52 at port 1. so we have to study signal 89s52 for detection and control purpose. We will give signal to optocouplers . optocouplers will give signal to H bridge circuit . optocoupler works as a isolator and as a switch.
Output of the microcontroller is connected to the optocoupler circuit. Here in this project we use ic pc 817 as a optocoupler to interface the microcontroller to small slow speed dc gear motor. One gear motor drive the vehicle and second gear motor change the front wheel of vehicle..
Power supply circuit.
In this project we use 9 volt battery to drive the vehicle. One 9 volt battery for the microcontroller circuit. Second 9 volt battery drive the motor driver circuit . Here in the project we one 5 volt regulator circuit. Output of the 9 volt dc is converted into 5 volt dc by using 7805 regulator circuit. Ic 7805 regulator converts the 9 volt dc into 5 volt dc with the help of the 5 volt regulator 7805.
VEHICLE CONTROL.
In this project we use two small gear dc motor for drive the small robot. One motor for the back wheel and one motor for the front wheel. Back motor drive the both tyre at a time and front motor control the direction of the vehicle . Here we use powerful gear dc motor instead of stepper motor. Stepper is not suitable for the drive the vehicle. Stepper motor is suitable for positioning sensor but gear motor is suitable for the vehicle drive.
Motors
To make the robots mobile we need to have motors and the control circuitry that could control the motors. There are different kinds of motors available for different application.
1. DC motor
2. Stepper motor
3. Servo motor
DC motors
These are the motors that are commonly found in the toys and the tape recorders. These motors change the direction of rotation by changing the polarity. Most chips can’t pass enough current or voltage to spin a motor. Also, motors tend to be electrically noisy (spikes) and can slam power back into the control lines when the motor direction or speed is changed.
Specialized circuits (motor drivers) have been developed to supply motors with power and to isolate the other ICs from electrical problems. These circuits can be designed such that they can be completely separate boards, reusable from project to project.
A very popular circuit for driving DC motors (ordinary or gearhead) is called an H-bridge. It’s called that because it looks like the capital letter ‘H’ on classic schematics. The great ability of an H-bridge circuit is that the motor can be driven forward or backward at any speed, optionally using a completely independent power source.
COMPONENTS USED
89s52 MICRCONTROLLER.
89C2051 MICROCONTROLLER. Is a 40 pin version of 52 family,. Program written for this controller is same for the 8051 controller. In this controller there is total 32 input and output pins. For controlling the process control.
OPTOCOUPLER ( PC 817) In this project we use optocoupler to provide a electrical isolation between process control circuit and motor drive circuit. In this project we use separate supply for processor and control circuit. Pc 817 is 4 pin ic. In this coupler two pin is input and two pin is output.
CRYSTAL. In this project we use two crystal. One for the dtmf decoder and second with the microcontroller Main use of the crystal is to provide a external frequency for the internal oscillator. With the dtmf decoder we use crystal 3.58 Mhz and with the microcontroller we use 12 Mhz crystal.
DC MOTOR. We use slow speed dc motor to drive the movement of vehicle. In this project we use two dc motor. One for the drive the vehicle and second motor to change the direction of the vehicle.
H BRIDGE LOGIC: H bridge logic is basically provide a forward and reverse logic to the motor.
