### Contactless Digital Tachometer using PIC Microcontroller

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:

Thank you Romel for this contribution. If anyone has doubts regarding this project, please use forum.

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#### Conversation

Mon Apr 27 2015, 08:14 PM
@Janvier This project is in assembly. It is unlikely anyone has a 'c' code
Mon Apr 27 2015, 04:47 PM
Janvier
hello! can u help me to find c code for a project called " automatic light controller with visitor counter". Best regards.
Mon Apr 27 2015, 05:27 AM
@mostfa.. it's a browser thing. Check your settings/try another browser.
Sat Apr 25 2015, 06:16 AM
rohan_verma
sir this circuit is tested?can i use it directly on developing PCB
Sat Apr 25 2015, 06:13 AM
rohan_verma
MSCOMM32.ocx cannot be copied in the systems folder even with administration rights.
Fri Apr 24 2015, 01:58 AM
mostfa
please fix the LCD Interfacing Tutorial as all pictures is gone
Fri Apr 24 2015, 01:57 AM
mostfa
LCD Interfacing Tutorial
Tue Apr 21 2015, 07:31 AM
hello every one i have made pic industrial and domestic timer and i can,t understand c code written in Hi-Tech please send me Mikroc code for this project anyone...................
Wed Apr 15 2015, 05:07 PM
@Bibek.. and everyone. Create threads if you need help. The chat box is just for chat
Wed Apr 15 2015, 05:06 PM
@mohd atif ..login..create a post/thread,then I can post a copy of the missing file

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##### Posted By ExperimenterUK
Sat Apr 25 2015, 06:03 PM
plz tell me how i edit this code file in MPLAB if ...
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Thu Apr 23 2015, 08:00 PM
Right click on the virtual terminal and turn on "E...
##### Posted By gsdvprasad
Thu Apr 23 2015, 12:49 PM
The LED scrolling display project. http://www.8051...
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Tue Apr 21 2015, 04:37 PM
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A multimeter won't help :(The most practical way i...
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As I don't have CRO, Can we test the crystal with ...
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i can,t understand C Code written in Hi-Tech pleas...
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Mon Apr 20 2015, 07:04 AM
k..let me make all this simple for u so u can add...
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Please zip and attach the code in future. You forg...
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Sun Apr 19 2015, 06:48 PM
It is really hard to say which course and/or insti...