Contactless Digital Tachometer using PIC Microcontroller

Hey friends, I should have posted this project last month itself but there was some problem with the circuit. [link], author of this project did an exellent job. I have been watching him learning on this website. He came as a total noob but now he is well versed with 8051 and PIC microcontroller. earlier he has submitted Microcontroller Based Home Security System



This project is about A Contactless Digital Tachometer. As per defination from wikipedia

A tachometer (revolution-counter, Tach, rev-counter, RPM gauge) is an instrument measuring the rotation speed of a shaft or disk, as in a motor or other machine. The device usually displays the revolutions per minute (RPM) on a calibrated analogue dial, but digital displays are increasingly common. The word comes from Greek Ταχος, tachos, "speed", and metron, "to measure".

wikipedia



Following diagram explains the logic of this project.



The infra red reflective object sensor work by simply emitting the infra red beam and when it encounter the white object surface than the infra red beam will be reflected back to the phototransistor; next the phototransistor and the 2N3904 transistor which formed the Darlington pair will start to conduct and will generate enough voltage across the 470 Ohm resistor to be considered by the PIC16f690 microcontroller build in Capture Compare Pulse width modulation(CCP )module input port as the logical "1". When the infra red beam encounters the black tire surface than both of the phototransistor and 2N3904 transistor will turn off; and the voltage across 470 Ohm resistor will drop to 3.5 volt (logical "0").

Therefore by timing the generated pulse period by the infra red reflective object sensor we could easily calculate the RPM using this following formula:

Frequency = 1/T Hz; T is the generated pulse period in second.

RPM (Rotation per Minute) = Frequency x 60

Here is a sample video of working project:



You can download project related files here:

Download Contactless Digital Tachometer project

Thank you Romel for this contribution. If anyone has doubts regarding this project, please use forum.
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ExperimenterUK
Sun Jan 25 2015, 08:10 PM
This box is for chat. Post problems in a suitable forum
ExperimenterUK
Sun Jan 25 2015, 08:04 PM
@gaurav.k Use the purple "Post reply" button. Green buttons often present a fresh edit box.
ExperimenterUK
Sun Jan 25 2015, 07:33 PM
@avianash..we have no entry for avianash.. Are you sure that is your login name ?
Fri Jan 23 2015, 04:29 AM
lolokijuh
DJ Bakal tulungan mo ako s IC Tester
Fri Jan 23 2015, 04:29 AM
lolokijuh
sir help about IC Tester
Thu Jan 22 2015, 01:59 PM
apparao majji
could you please help in programming
Thu Jan 22 2015, 10:13 AM
avianash
hi my account is inactive plz help me
gaurav.k
Thu Jan 22 2015, 07:04 AM
not able top post any reply from my login... after pressing "post Reply "it takes me to a blank page
Thu Jan 22 2015, 04:06 AM
frankie
friend, that modification should be done in the program so that led up and down oscillation is one blink, thanks
Wed Jan 21 2015, 05:06 PM
Gargiarya
to get a clear view of seven segment with 8051 visit http://www.mechaterrain.com/seven-segment-fixed-display-using-8051

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nawfel
Sat Jan 17 2015, 07:27 AM
Rohi123
Sat Jan 10 2015, 11:00 AM
safakarici
Fri Jan 09 2015, 08:55 PM
Nikita_Pinjare
Thu Jan 08 2015, 03:10 PM
mayank058
Wed Jan 07 2015, 05:43 AM
Overeating
Tue Jan 06 2015, 05:56 AM
trancebreaker11
Sun Jan 04 2015, 07:42 AM
akash474001
Thu Jan 01 2015, 05:49 AM

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ExperimenterUK Avatar
Posted By ExperimenterUK
Sun Jan 25 2015, 08:19 PM
According to this page the output is fairly linear...
mayank058 Avatar
Posted By mayank058
Thu Jan 22 2015, 12:16 PM
dear sir, Now i want to generate a si...
mayank058 Avatar
Posted By mayank058
Tue Jan 20 2015, 06:40 AM
dear sir, Now its working properly. Th...
ajay_bhargav Avatar
Posted By ajay_bhargav
Tue Jan 20 2015, 04:36 AM
ajay_bhargav Avatar
Posted By ajay_bhargav
Tue Jan 20 2015, 04:35 AM
I found another issue with your code:calling PWMIn...
mayank058 Avatar
Posted By mayank058
Mon Jan 19 2015, 05:47 AM
dear sir, Please do it for me..
PsySc0rpi0n Avatar
Posted By PsySc0rpi0n
Sun Jan 18 2015, 08:23 PM
But it's a way to debug to consider to the future ...
ajay_bhargav Avatar
Posted By ajay_bhargav
Sun Jan 18 2015, 06:04 AM
I remember i created small library for lpc23xx ser...
ajay_bhargav Avatar
Posted By ajay_bhargav
Sun Jan 18 2015, 06:00 AM
It's obviously a personal choice. Digging into map...
ajay_bhargav Avatar
Posted By ajay_bhargav
Sun Jan 18 2015, 05:58 AM
@karan123 I suggest you to create a new thread for...