Present project is designed using 8051 microcontroller to avoid railway accidents happening at unattended railway gates, if implemented in spirit. This project utilizes two powerful IR transmitters and two receivers; one pair of transmitter and receiver is fixed at up side (from where the train comes) at a level higher than a human being in exact alignment and similarly the other pair is fixed at down side of the train direction. Sensor activation time is so adjusted by calculating the time taken at a certain speed to cross at least one compartment of standard minimum size of the Indian railway. We have considered 5 seconds for this project. Sensors are fixed at 1km on both sides of the gate. We call the sensor along the train direction as ‘foreside sensor’ and the other as ‘aft side sensor’. When foreside receiver gets activated, the gate motor is turned on in one direction and the gate is closed and stays closed until the train crosses the gate and reaches aft side sensors. When aft side receiver gets activated motor turns in opposite direction and gate opens and motor stops. Buzzer will immediately sound at the fore side receiver activation and gate will close after 5 seconds, so giving time to drivers to clear gate area in order to avoid trapping between the gates and stop sound after the train has crossed.
The same principle is applied for track switching. Considering a situation wherein an express train and a local train are traveling in opposite directions on the same track; the express train is allowed to travel on the same track and the local train has to switch on to the other track. Two sensors are placed at the either sides of the junction where the track switches. If there’s a train approaching from the other side, then another sensor placed along that direction gets activated and will send an interrupt to the controller. The interrupt service routine switches the track. Indicator lights have been provided to avoid collisions. Here the switching operation is performed using a stepper motor. Assuming that within a certain delay, the train has passed the track is switched back to its original position, allowing the first train to pass without any interruption. This concept of track switching can be applied at 1km distance from the stations.
Railways being the cheapest mode of transportation are preferred over all the other means .When we go through the daily newspapers we come across many railway accidents occurring at unmanned railway crossings. This is mainly due to the carelessness in manual operations or lack of workers. We, in this project has come up with a solution for the same. Using simple electronic components we have tried to automate the control of railway gates. As a train approaches the railway crossing from either side, the sensors placed at a certain distance from the gate detects the approaching train and accordingly controls the operation of the gate. Also an indicator light has been provided to alert the motorists about the approaching train.
Using the same principle as that for gate control, we have developed a concept of automatic track switching. Considering a situation wherein an express train and a local train are travelling in opposite directions on the same track; the express train is allowed to travel on the same track and the local train has to switch on to the other track. Indicator lights have been provided to avoid collisions .Here the switching operation is performed using a stepper motor. In practical purposes this can be achieved using electromagnets.
The project consists of four main parts:
- 8051 microcontroller
- IR Transmitter
- IR Receiver
- Stepper Motor Circuit
The aim of this article is to get familiarized with the modern field of robotics and to find the technology know -how. Also here we are using the sophisticated emerging technology -embedded system. Here we have designed a robot arm, controlled by a microcontroller. We choose this deign because it is the most common form of robot we can find anywhere in industries like car assembling, bottling plant, packing section etc. The driver circuits for these motors are to be controlled using 8051 microcontroller with a control key panel. The movement is established using stepper motors. pick and place robots are the small robots using for continuous purpose in the industries then let us go through some thing about pick and place robot by this article .
WHAT IS A ROBOT?
Robot is any machine that does work on its own, automatically after it is programmed by humans. HISTORY OF ROBOTS:
The first robot’s name was Electro and his dog’s name was Sparko .They appeared at the New York world’s fair in 1939. While plugged in, Elektro could say 77 words and move backwards and forwards.
In1920’s, Karl Capek from Czechoslovakia introduced the words first robot on stage.
PICK AND PLACE ROBOT
We are going to design & implement a small model of pick and place robot, which pick and place object any where with in 360degrees and 30 cm diameters around it. The reason for choosing project is, the most extensively form of machine is used in most of the industries like car manufacturing, shipyards, assembling machine etc.
MICROCONROLLERS FOR EMBEDDED SYSTEMS
Microprocessors and microcontroller are widely used in embedded system products.
An embedded system is a system which is dedicated for a single purpose remains unchanged through out its entire life time. An embedded product uses a microprocessor (or microcontroller) to do one task and one task only.
A stepper motor is a widely used device that translates electrical pulses into mechanical movement. It is used for precise position control. # Increase or decrease the RPM (speed) of it.
To vary the RPM of motor we have to vary the PRF (Pulse Repetition frequency). Number of applied pulses will vary number of rotations and last to change direction we have to change pulse sequence.
The circuit mainly consists of three modules -control system, user interface module & a high voltage driver. A control system is nothing but the microcontroller. It has got the following modules.
- User Interface Module.
- Pulse Generator Module.
- Timing Control Module.
- Output Module.
When the keys are pressed the current flows directly to the ground due to the low resistive path making no more current available to the port pins pulling it down to low state, so when ever the keys are pressed the corresponding pins are pulled down. So normally every pin are at a high state giving a value of 1 when ever the keys are pressed the pins are to the low state giving the value 0.
This change is constantly monitored to check for any user interaction. The microcontroller constantly monitors port 0 for any change in port value and if it finds any change it generates the appropriate control signals. The stepper motor driver circuit consists of two stages-low power switching stage& high power switching stage. The function of the low power switching stage is to boost up the low power signal output from the micro controller to a high power signal so as to drive the power transistor.
Care should be taken while connecting the circuit to the motor as stepper has got a tendency to produce very high reverse current compared to DC motor.
To protect the circuit for this reverse current we have connected a diode in reverse bias across the coil supply so that whenever reverse current is present this diode will sink it protecting the circuit.
The main objective of this project is to implement an Pass word Based Door Locking System Using AT89c51 Microcontroller.
Security is a prime concern in our day-today life. Everyone wants to be as much secure as possible. An access control for doors forms a vital link in a security chain. The microcontroller based Door locker is an access control system that allows only authorized persons to access a restricted area. The system is fully controlled by the 8 bit microcontroller AT89C51 which has a 2Kbytes of ROM for the program memory. The password is stored in the EPROM so that we can change it at any time.
The system has a Keypad by which the password can be entered through it. When the entered password equals with the password stored in the memory then the Stepper motor rotate forward side so that the door is opened. If we entered a wrong password for more than three times then the Alarm is switched on. When we go inside and come back then the microcontroller will sense the person using the IR, the microcontroller will automatically open the door for you.
The default password is 1111 and you can change the password by dialing 1234, old password, and new password #button. for example if you want to change the password from the default to 4523 then dial 123411114523# after dialing you can hear a beep sound which confirm the operation goes successful.
- AT89c51 Microcontroller
- Stepper motor
- ULN2003 Motor Driver
- 5V Buzzer
- Embedded C
- KEIL Demo Version with Simulator