11-10-2016, 12:03 PM
1458587725-PROJECTREPORT.doc (Size: 1.04 MB / Downloads: 4)
Introduction
Present project is designed using PIC microcontroller to avoid railway accidents happening at unattended railway gates. This project utilizes four powerful IR transmitters and four receivers whenever train passes gate will automatically gets closed and after passes gate will be opened.
Features :
• Easy to use for day to day operation.
• Stand alone device – no computer or any other hardware required.
• Needs to be programmed only once.
• Easy to program.
• Uses IR sensor.
Benefits :
• Eliminates human error
• No manual intervention
• Saves man power and money.
• Easy programming with the help of manual.
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. 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
Description
TSAL6200 is a high efficiency infrared emitting diode in GaAlAs on GaAs technology, molded in clear, bluegrey tinted plastic packages.
In comparison with the standard GaAs on GaAstechnology these emitters achieve more than 100 % radiant power improvement at a similar wavelength.
The forward voltages at low current and at high pulse current roughly correspond to the low values of the standard technology. Therefore these emitters are ideally suitable as high performance replacements of standard emitters.
Features
• Extra high radiant power and radiant intensity
• High reliability
• Low forward voltage
• Suitable for high pulse current operation
• Standard T-1¾ (5 mm) package
• Angle of half intensity = ± 17°
• Peak wavelength = 940 nm
• Good spectral matching to Si photodetectors
Applications
• Infrared remote control units with high power requirements
• Free air transmission systems
• Infrared source for optical counters and card readers
• IR source for smoke detectors
Description
The TSOP17 series are miniaturized receivers for infrared remote control systems. PIN diode and preamplifier are assembled on lead frame, the epoxy package is designed as IR filter. The demodulated output signal can directly be decoded by a microprocessor. TSOP17 is the standard IR remote control receiver series, supporting all major transmission codes.
Features
• Photo detector and preamplifier in one package
• Internal filter for PCM frequency
• Improved shielding against electrical field disturbance
• Low power consumption
• High immunity against ambient light
• Continuous data transmission possible(upto2400bps)
• TTL and CMOS compatibility
• Output active low
• Suitable burst length 10 cycles/burst
The circuit of the TSOP17 is designed in that way that unexpected output pulses due to noise or disturbance signals are avoided. A bandpassfilter, an integrator stage and an automatic gain control are used to suppress such disturbances. The distinguishing mark between data signal and disturbance signal are carrier frequency, burst length and duty cycle. The data signal should fullfill the following condition: • Carrier frequency should be close to center frequency of the bandpass (e.g. 38kHz). •
Burst length should be 10 cycles/burst or longer. After each burst which is between 10 cycles and 70 cycles a gap time of at least 14 cycles is neccessary. • For each burst which is longer than 1.8ms a corresponding gap time is necessary at some time in the data stream. This gap time should have at least same length as the burst. •
Up to 1400 short bursts per second can be received continuously. Some examples for suitable data format are: NEC Code, Toshiba Micom Format, Sharp Code, RC5 Code, RC6 Code, R¬2000 Code, Sony Format (SIRCS).
When a disturbance signal is applied to the TSOP17.. it can still receive the data signal. However the sensitivity is reduced to that level that no unexpected pulses will occur. Some examples for such disturbance signals which are suppressed by the TSOP17.. are: • DC light (e.g. from tungsten bulb or sunlight) • Continuous signal at 38kHz or at any other frequency • Signals from fluorescent lamps with electronic ballast (an example of the signal modulation is in the figure below).
The 555 Timer IC is an integrated circuit (chip) implementing a variety of timer and multivibrator applications. The original name was the SE555 (metal can)/NE555 (plastic DIP) and the part was described as "The IC Time Machine".
The standard 555 package includes over 20 transistors, 2 diodes and 15 resistors on a silicon chip installed in an 8-pin mini dual-in-line package (DIP-8).Variants available include the 556 (a 14-pin DIP combining two 555s on one chip), and the 558 (a 16-pin DIP combining four slightly modified 555s with DIS & THR connected internally, and TR falling edge sensitive instead of level sensitive).
Ultra-low power versions of the 555 are also available, such as the 7555 and TLC555.The 7555 requires slightly different wiring using fewer external components and less power.
The 555 has three operating modes:
• Monostable mode: in this mode, the 555 functions as a "one-shot". Applications include timers, missing pulse detection, bouncefree switches, touch switches, frequency divider, capacitance measurement, pulse-width modulation (PWM) etc
• Astable - free running mode: the 555 can operate as an oscillator. Uses include LED and lamp flashers, pulse generation, logic clocks, tone generation, security alarms, pulse position modulation, etc.
• Bistable mode or Schmitt trigger: the 555 can operate as a flip-flop, if the DIS pin is not connected and no capacitor is used. Uses include bouncefree latched switches, etc.