Measuring RPMs using PIC16F877

siphorob · Joined: 12 Oct 2010 Posts: 12 Location: South Africa

Hi,

I'm using a hall effect sensor to calculate the speed of a dc motor, I tried a couple of Examples listed in CCS with very little luck.

Please help.
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Regards,
Brandon

jacqueskleynhans · Posted: Sun Oct 24, 2010 9:38 am

Hi Brandon, You have to be more clear than that.

Post your code that you have so far with your compiler v.
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siphorob · Joined: 12 Oct 2010 Posts: 12 Location: South Africa

Hi,

I am using the example in EX_FREQC.C:

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Code removed.

Reason: Forum Rule #10

10. Don't post the CCS example code or drivers, or ask for such code and drivers.
http://www.ccsinfo.com/forum/viewtopic.php?t=26245

-- Forum Moderator
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Regards,
Brandon

siphorob · Joined: 12 Oct 2010 Posts: 12 Location: South Africa

Was the information provided enough?
Please advise.
_________________
Regards,
Brandon

SherpaDoug · Joined: 07 Sep 2003 Posts: 1640 Location: Cape Cod Mass USA

When you say you had very little luck, what happened? What did it do that it should not have, or what didn't it do that it should have? Did it hang? Did it give bad numbers? Zeros? Etc.
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PCM programmer · Joined: 06 Sep 2003 Posts: 21708

siphorob,
Use the forum's search page to find code for this. There is a link to
the Search page at top of the forum. Search for this:

biozen · Joined: 08 Sep 2010 Posts: 10

We use Allegro gear tooth sensors for a product. The sensors produce a square wave which 'reflects' when the gear tooth passes across the sensor. Use the External Interrupt on the PIC to catch the rise/fall that indicates a gear tooth just passed. Using a timer you can measure the time between the two (or more) gear teeth. Do the maths there after to get the RPM...

We use a gear of 16 teeth. Start the timer and start counting the teeth. At the end of 16 counts of gear, stop and read timer. Average this over a few readings. This is the time for one rotation.

HTH,
Mohit.

siphorob · Joined: 12 Oct 2010 Posts: 12 Location: South Africa

Dear PCM programmer,

I have tried a variety of samples found on the search results, the problems I have with code is very vague, or does not work completely.
Some of the treads are left with no conclusions. Is there a thread that maybe has a good solution?

Kind Regards,
Brandon

[email protected]

siphorob · Joined: 12 Oct 2010 Posts: 12 Location: South Africa

I also tried using the count.c program on this thread:
http://www.ccsinfo.com/forum/viewtopic.php?t=41877
_________________
Regards,
Brandon