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ABSTRACT:
The Dynamic Speed Governor is a system that can be implemented effectively for an efficient and perfectly controlled traffic system. This system can limit the speed of a moving vehicle over an area where the speed has to be restricted and retained within a predetermined value. The Dynamic Speed Governor consists of mainly two parts, the Transmitter section and the Receiver section. The transmitter section is mounted on the signal board, on which the speed limit over that area is indicated. Receiver section is kept inside the vehicle. The radio frequency signal from the transmitter is transmitted and the receiver receives it. If the speed of the vehicle is greater than the speed limit proposed for that particular area, which in turn is transmitted by the transmitter section, the speed governor comes into action and restricts the driver from going beyond that rated speed. If the system detects that the speed of the vehicle has gone beyond the speed limit, a signal is generated from the dynamic speed governor circuit. This signal in turn is used to drive the mechanical part of the vehicle, which closes the fuel nozzle of the vehicle thereby restricting the vehicle from going beyond that speed. In this particular reproduction of the system, to indicate the signal produced, the signal output from the circuit is used to trigger a monostable multi-vibrator, which in turn sounds a buzzer.
INTRODUCTION
The proposed mini project work is a Dynamic Speed Governor. Dynamic speed governor is designed with the aim of dynamically limiting the speed of the vehicle to a preset value, when the driver drives through an area that has a preset speed limit, thereby encouraging safe driving and preventing accidents. The main idea is to transmit the speed limit for the area to the vehicle, as it approaches an area that has speed restriction, so that the driver can be warned and the speed of the vehicle is automatically reduced. The system is implemented with the help of a RF transmitter that transmits a speed limit to the approaching vehicle, and an RF receiver inside the vehicle that accepts the incoming signal and then feeds the speed limit as one of the inputs to a comparator. The other input of the comparator comes from a digital tachometer. When the comparator detects an input speed that is greater than the speed limit received by the RF receiver, it will trigger off a chain of reactions that induce the mechanical functioning of the vehicle to automatically bring down the speed of the vehicle to a range in tandem with the preset value and thus the desired results are obtained from the system.
OBJECTIVES
The primary design criteria for this project work were as follows:
 Incorporate easily available components
 Use cheap and easily worked materials platform
 Minimize the weight of the unit
 Maintain a level of robustness
 Bring about solid design and construction features
 Limit the consumption of energy
 Modular design

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DYNAMIC SPEED GOVERNORS
Introduction
With the of aim of dynamically limiting the speed of the vehicle to a preset value.
Presently available option-Static governors.
Static governors have the limitation of setting the maximum speed of the vehicle.
The main idea is to transmit the speed limit for the area to the vehicle, as it approaches an area that has speed restriction, so that the driver can be warned and the speed of the vehicle is automatically reduced.
An RF transmitter used in the system transmits a speed limit to the approaching vehicle and the RF receiver inside the vehicle receives this signal.
The comparator present inside the vehicle compares the received speed and the vehicle speed to give an output.
This output can be used to control the governor in the vehicle there by controlling the speed.
Components of the System
RF transmitter unit (HT 640)
Sensor unit
RF receiving unit(HT 648)
Digital tachometer unit
Seven segment display device
Display drivers
Comparator
Alarm unit
Objective
The primary design criteria for this project work were as follows:
Incorporate easily available components
Use cheap and easily worked materials platform
Minimize the weight of the unit
Maintain a level of robustness
Bring about solid design and construction features
Limit the consumption of energy
Modular design
Block Schematic of Transmitter Section
Block Schematic of Receiver and Tachometer Section
RF Transmitting Unit
Consists of
A sensor unit
Transmitting unit
First section consist of a sensor unit, mono-stable vibrator, astable multi vibrator.
Sensor unit consists of a LDR and photo diode.
Followed by a mono-stable vibrator and astable vibrator.
Receiver Module
Seven Segment Display
NUMBER OF PULSES TO SPEED (KM/HR) CONVERSION
Speed in km/hr = distance traveled in km in 1 hr.
Also, speed in km/hr = distance traveled in km in (1/a) hr × a
Where ‘a’ is the scaling factor and (1/a) hr is the measuring time.
Now, distance travelled in (1/a) hr = number of rotations in (1/a) hr × 2π × radius of wheel.
Counter value = D1hr = D (1/a) hr × a
= 2Nr× π ×r×a
But counter value = number of pulses counted = Np
Hence Np = 2Nr × π × r × a.
Np/Nr= 2 π × r × a.
We take Np/Nr = 1 i.e. no scaling which means that sensor output is directly coupled to counter.
Therefore, 1 = 2 π ×r × a
a = 1/(2 π ×r).
Here we take the radius of the wheel as,
22.5 cm = 22.5×10-5 km.
Value of a = 1/(2 π × r) = 707.35
Hence measuring time = (1/a) hr
= 3600 sec/707.35
= 5.08 sec
Therefore the measuring time is approximately taken as 5 seconds.