16-05-2012, 01:49 PM
RF based speed control of vehicles in school zones
RF based speed control of vehicles in school zones.pdf (Size: 49.67 KB / Downloads: 150)
Nowadays people are driving very fast, accidents are occurred more frequently,
we loss our valuable life by making small mistake while driving. So to avoid such
kind of accidents, it is necessary to alert the driver and to control the speed of
vehicle automatically.
The main objective of this project is to develop signaling unit to indicate the type
of zone to the vehicle and to control the vehicle speed. Every zone like school,
highway and etc may have a transmitter tag to transmit the zone information by
RF signal. This signal should be received by the vehicles and accordingly varies
the speed limit of the vehicle. In practical, an actuator may be used to control the
throttle of the vehicle. But to show the demo module here we used a DC motor,
and varying the speed of it.
Transmitter Block
Receiver Block
Transmitter Block
This block contains a micro controller (AT89C2051) and a RF module. The zone
information is pre-programmed in the micro controller. The micro controller sends
the zone code in serial data format to the RF module. The RF Module gets the
serial data and modulates data with 433Mhz carrier. The modulation is Amplitude
Shift Keying (ASK) type.
Receiver Block
The signal transmitted by the transmitter tag is received by a RF module. The RF
module is tuned to 433Mhz. The RF module demodulates the carrier and
reproduces the serial data. The reproduced serial data is send to the micro
controller (AT89C51). The firmware stored in Micro controller decodes the serial
data and finds the zone and accordingly it varies the DAC (Digital to Analog
Converter) data. The DAC produces analog signal in the range of 0-5V, which is
fed to the power driver circuitry. The power driver varies the power of DC motor.
For example if it is school zone, the tag sends the school zone code. The
receiver gets the information and reduces the DC motor speed.
The application program (firmware) for the micro controller will be written in
embedded ‘C’ and will be stored in the flash memory of the micro controller.