DESIGN CONSTRUCTION & IMPLEMENTATION OF DIGITAL RPM & FARE METER

Presentation on DESIGN CONSTRUCTION & IMPLEMENTATION OF DIGITAL RPM & FARE METER

Objectives

1. Design, construction & implementation of a digital RPM meter & FARE meter.
2. Performance test of the rpm meter & fare meter.
3. To remove the drawbacks of the measurement techniques.
4. To make rpm meter for certain speed range.
5. To make the project cost effective.
6. To study the working principle & characteristics of all components.

Importance of speed measurement

1. To take a signal representing the demanded speed.
2. Different drive platforms need to synchronize wheel speed.
3. Motor must rotate at its rated speed, otherwise it cannot work efficiently.

Why use low range rpm meter?

1. High speed rpm meter is available in market. If we use the same meter for any range of speed, this will not be cost effective.
2. Low range rpm meter is less complex.

Technique of speed measurement

1. Speed measurement can be done by two methods: invasive & noninvasive.
2. Here we use noninvasive method.
3. It is better technique than invasive.
4. We use IR LED & photodiode in our project.
5. We can use LASER but it has harmful effect on eyes if ray cannot control.

Importance of digital fare meter in Bangladesh

Digital fare meter is used in taxicab & in CNG. We have to import it from abroad but it is costly. If we can make it in our country, we will try to minimize its cost of the present time. Passenger or driver cannot bargain with each other about the fare if fare meter is set up.

Working principle

In case of measure the speed of a motor, we connect a reflector to the shaft of the motor. The IR LED continuously generates a light of infrared wavelength. Light wave falls on the reflector, it reflects to the receiver photodiode and it produces a current which is amplified by its action which shows equivalent  rpm of the motor.

Block diagram representation

 

Methodology

In In order to obtain our objectives we follow particular methodology:

Operational wave shape

Circuit Diagram

Real-time Connection

Receiver Output

Mathematical Interpretation

In 1s no. of pulse	=	N
In 60s no. of pulse	=	60 N
So, speed(rpm)	=	no of rotation in 60s /1
	=	60N
Fare-1	=	Tk. 14 (For 1st 2 km)
Fare-2	=	Distance * Tk./km (Distance ≥ 2km)
Total Fare	=	Fare-1 + Fare-2

Comparison with RPM meter in lab

N.B. From the performance table we can see that the accuracy increase with the rpm of the vehicle. We have taken these data before our supervisor was coming. But due to maladjustment voltage sparks and our voltage regulating IC, microcontroller & LCD display were damaged. The equipments are not available in Chittagong & the time was too short to buy them from Dhaka and present it in our project show. We will show it to our supervisor teacher after our final presentation which was said by our supervisor.