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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Conversation

Tue Mar 03 2015, 06:59 AM
candyyyy
Hi! Can i ask how do you connect the Vo contrast pin? Do i leave it open?
ExperimenterUK
Sun Mar 01 2015, 07:06 AM
@Anupam Biswas..post all you have done in the GSM forum
Sat Feb 28 2015, 02:51 PM
Anupam Biswas
I am doinga project on gsm based home automation.I have done alittle study about at commands.I am using Atmel 89c51 with yhe gsm module.I am unable to receive any message via the module.The simulation is done on proteus and i am using a virtual terminal.Can anyone please help me?Thanks in advance.
Tue Feb 24 2015, 12:47 AM
MrCurious
is Stat a global variable too? you reference it in Chan's "disk_status" function.
Sat Feb 21 2015, 09:10 PM
Harikumar
കൊള്ളാം
ExperimenterUK
Fri Feb 20 2015, 06:28 AM
@sugikz.. I have asked Ajay about it, he'll soon sort it out
Thu Feb 19 2015, 12:22 PM
sugikz
"Sorry no bots allowed! You entered two different email addresses. Please enter a valid email address in the two fields provided"
Thu Feb 19 2015, 12:21 PM
sugikz
this are the problem notice box;
Thu Feb 19 2015, 12:20 PM
sugikz
yes, i still got stuck on email problem, i've used gmail, yahoo, and told some friends of mine to sign up on the site, but they face the same problem as iam,
Thu Feb 19 2015, 05:48 AM
sjeeva
hi, is any doing a project on raspberry pi

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MALIKATIF
Mon Mar 02 2015, 04:47 PM
raamchandran
Mon Mar 02 2015, 11:20 AM
ABiDAEV
Sat Feb 28 2015, 11:31 PM
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Wed Feb 25 2015, 05:28 AM
sugikz11
Wed Feb 25 2015, 04:23 AM
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Sat Feb 21 2015, 02:00 AM
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Thu Feb 19 2015, 12:50 PM

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steve_yu_chan Avatar
Posted By steve_yu_chan
Tue Mar 03 2015, 04:32 PM
Dear All ,can you help me to solve the regarding t...
ABiDAEV Avatar
Posted By ABiDAEV
Sun Mar 01 2015, 11:42 AM
Thanks for sharing, but can you please update the ...
sankalp_s Avatar
Posted By sankalp_s
Thu Feb 26 2015, 09:27 PM
What are you trying to make ?ExperimenterUKsir i w...
ExperimenterUK Avatar
Posted By ExperimenterUK
Thu Feb 26 2015, 12:58 AM
We seem to be moving away from the original projec...
ajay_bhargav Avatar
Posted By ajay_bhargav
Wed Feb 25 2015, 02:02 PM
You will need a 64 bytes buffer that will be writt...
PsySc0rpi0n Avatar
Posted By PsySc0rpi0n
Wed Feb 25 2015, 09:24 AM
I've already read that tutorial and almost all oth...
ajay_bhargav Avatar
Posted By ajay_bhargav
Wed Feb 25 2015, 04:56 AM
brightness control is going to be tough job as you...
ajay_bhargav Avatar
Posted By ajay_bhargav
Wed Feb 25 2015, 04:36 AM
I've already read that tutorial and almost all oth...
sankalp_s Avatar
Posted By sankalp_s
Tue Feb 24 2015, 07:18 PM
The attached code is for up to 16 LEDs.Just point ...
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Posted By sankalp_s
Tue Feb 24 2015, 07:16 PM