The Vehicle speed detection is a method having a very important application worldwide. Radio Detection and Ranging (RADAR) is an electromagnetic device for detecting the presence, location and speed of objects. The presence of objects and their speed are determined by the transmission and return of electromagnetic energy. In modern systems Doppler shift based method is used in the measurement of vehicle speed.
Using the Doppler Effect is a great way to measure relative speed. In practice, the Doppler Effect is a shift in frequency perceived by a receiver from a signal source due to relative movement of the sender and / or receiver. In a Doppler radar system, a known frequency signal is transmitted from an antenna which is pointed at a reference object. A separate antenna is used to receive the signal that is reflected back from the reference to measure the Doppler shift of the signal. A simple Doppler module, also called as the microwave motion sensor, can be easily integrated into multiple types of systems for various purposes. Doppler modules have an internal oscillator used to produce the signal frequency transmitted as the source. The received signal is then mixed with this set signal, which produces an output that is a sinusoid containing the frequency difference between the sender and receiver signals. Usually, these values need to be processed is usually done with the help of a microcontroller.
The advantages of the use of microwave sensor modules in RADAR technology are these are very compact, having high gain and highly directional antennas. Speed is measured by distance travelled by an object with respect to time. In Doppler RADARs when a moving target is detected by a continuous wave RADAR signal, frequency shift occurs in the return signal given by Doppler frequency shift, fd=2f/c, where f is the transmitted frequency and c is the velocity of light. When the target is moving toward the RADAR receiver, the signal frequency increases by fd and when it is moving away from the receiver the frequency decreases by fd. Most of the modern systems use complex analysis and processing of output signals by using expensive digital signal processors and microcontrollers.
Radar speed signs by the side of the roads that caution vehicle driver about his/her speed and the speed limits. An over-speeding vehicle may voluntarily drive at the prescribed speed limits after reading the Radar speed sign. The traffic police can find out the speed of vehicles and over-speeding vehicles can be punished or fined againts any violations in speed limits by vehicle drivers. One of the major reasons for road accidents is vehicle overspeed.
We are here using HB100 Doppler Radar Sensor. It does not have in built amplifier so we need to design op-amp based amplifier having high gain. The amplified output is then given to microcontroller Atmega328 for processing which shows vehicle speed on 16×2 LCD dsiplay. We can also use seven segment display.
SOFTWARE :
- ARDUINO IDE
- EMBDDED CPP CODE
HARDWARE :
- HB100 MICROWAVE SENSOR MODULE
- SIGNAL AMPLIFIER
- ARDUINO UNO (ATMEGA328)
- 16X2 LCD DISPLAY
Technical Specifications Of HB100:
- Working Voltage : 5V
- Working Current : 30 ma
- Detection Range : 2 meter-16 meter
- Frequency : 10.52 Ghz
- Output Power : 12 dBm
- Vertical Beam Width : 36 degree
- Horizontal Beam Width : 72 degree