PROJECT REVIEW- II

ELECTRONICS & COMMUNICATION ENGINEERING

MICROCONTROLLERBASED

SPEEDOMETERCUM

ODOMETER

S.NO BATCH MEMBERS REG.NO

1. P.ANISH 11410524

2. B.ANNAMALAI 11410525

3. C.ARUNKUMAR 11410526

4. A.GOKUL 11410530

5. S.GOKULAKRISHNAN

11410531 GUIDED BY

MRS.K.SUMATHI B.E., MISTE , (M.E)

OBJECTIVE: The aim of the project is to display the speed and distance covered by a vehicle per hour in digital. So that even a normal person can easily understand the readings.

SYNOPSIS: In this project we make use of a speed transducer. The rotation of the wheel is sensed by the combined action of a reed switch and a magnet fixed on the wheel. The sensor sends a pulse to the microcontroller each time a revolution is made using optocoupler and it is counted by the counter present in microcontroller. This count value is used to measure the speed and distance using the standard readings present in the memory. The speed and distance are displayed in LCD. The circuit uses a microcontroller AT89C2051, an LCD display, sensor, serial EEPROM and some commonly available components. It is very accurate when compared to analog meter. It is reliable due to use of microcontroller. It reset to zero after completion of 99,999.9km.. It is easy to build and fix on any vehicles.

LCD DISPLAY 16X2 EL1602MAGNET

IN WHEEL

REEDSWITCH

OPTOCOUPLER 4N35

MICROCONTROLLER ATC89C 2051

TIMER

SERIALEEPROM24C02C

VOLTAGEREGULATOR

7805

POWERSUPPLY12V DC

BLOCK DIAGRAM

REED SWITCH

The Reed Switch described above is a 1 Form A (normally open (N.O.)or Single Pole Single Throw (SPST)) Reed Switch

Many reed switches and reed sensors are used for proximity sensing and are activated by a magnet. As the magnet is brought into the proximity of the reed sensor/switch, the device activates. As the magnet is removed from the proximity of the reed sensor/switch, the device deactivates. However, the magnetic interaction involved in activating the reed switch contacts is not necessarily obvious. One way of thinking about the interaction is that the magnet induces magnetic poles into the metal parts of the reed switch and the resulting attraction between the electrical contacts causes the reed switch to activate.

WORKING OF REED SWITCH

MICROCONTROLLER

Features - AT89C2051 Compatible with MCS-51 Products2K Bytes of Reprogrammable Flash Memory2.7 to 6V Operating RangeFully Static Operation: 0 Hz to 24 MHzTwo-level Program Memory Lock128 x 8-bit Internal RAM15 Programmable I/O LinesTwo 16-bit Timer/CountersSix Interrupt SourcesProgrammable Serial UART ChannelDirect LED Drive OutputsOn-chip Analog ComparatorLow-power Idle and Power-down Modes20-pin DIP

EEPROM

AT24C02 is an electrically erasable and programmable ROM. It has a 2Kbits of memory size arranged in 32 pages of 8 byte each. There are 256 (32 x 8) words each of one byte. The data is transferred and received serially through serial data (SDA) pin.

LCD DISPLAY

Calculations

You first need to know the radius of the bike’s front wheel. The calculations here are based on Hero Honda’s Splendor model. The radius of the front wheel is 30 cm. (This can vary with the brand or model.)

Circumference of the wheel= 2πr(where ‘r’ is in cm)

= 2×3.14×30= 188.4 cm or 1.884 meters

Speed. Let’s assume that in 1 second the wheel completes one revolution. In other words, in one second, the bike has covered 1.88 meters. Therefore the speed in km/hour:

N×1.88×3600/1000 =N×6.784 or N×6.8

where ‘N’ is the number of revolutions per second. ‘6.8’ is a constant and only ‘N’ varies; for example, if ‘N’ is 5, the speed equals 5x6.8= 34 km/hour.Distance. The odometer is updated every 100 meters. To cover 100 meters, the wheel is required to make approximately 53 revolutions (100/1.88). The microcontroller takes care of the tasks of revolutions counting, speed calculation, conversion and display of results.

APPLICATION: 

It is used in motorbikes to display the speed in digital

It is used in cars to display the speed in km/hour

ADVANTAGE:1. Digital readout2. Speed displayed in km/hour3. Distance traveled displayed in Kilometers4. Readings saved in non-volatile memory (EEPROM)5. Reliability due to use of the microcontroller6. No mechanical wear and tear