rpm counter

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mnoman

Joined: 26 Feb 2006
Posts: 10

15 Aug 2006 15:18 counter timer 8052 rpm

i want to make a rpm counter using simple IR LED and detector using the slotted disk and interface it with 89c51 can any one just give me the idea how it may be possible

amrstaha

Joined: 29 Aug 2005
Posts: 141
Helped: 6
Location: Egypt

15 Aug 2006 21:20 download rpm counter 2006

count the number of pulses (p) coming from your sensor for a period 1 second. Depending the number of pulses per revolution (no of teeth of your disk): n

RPM=p/n*60

The 1 second delay can accurately adjusted with the help of a timer, and you may pull the sensor input. Or you can count the pulses using an external interrupt while looping in an accurately calculated 1 seond software delay loop.

You may shorten the 1 second delay for a quicker response. But for the sake of just display, I think the 1 second delay is satisfactory.

ferika

Joined: 11 Jul 2006
Posts: 3

16 Aug 2006 11:35 infrared led sensor rpm counter

If the turn frequency is too slow, you may make others - use your signal as gate signal for an highspeed clock generated in one internal timer of 8051. You become the the length of your pulses measured in the peride of the internal clock. This methode is better even if the external turn-signals are relatively slow.

smxx

Joined: 18 Aug 2005
Posts: 188
Helped: 8
Location: iran(ahwaz)

16 Aug 2006 14:08 rpm counter

hi
It can be made by using interrupt .
when a rellected signal recive to IR detector an interrupt occur and a counter begain to count .in next interrupt first reed counter ,rest and begain to count.

yuo can use captuer mode of timer2 in 8052.

hameeds01

Joined: 23 Aug 2005
Posts: 308
Helped: 15
Location: NUST Islamabad

17 Aug 2006 5:41 rpm = (1/time) * 60

How to generate an interrupt of 1 sec by using timer 2 it’s a 16 bit timer .as my friend told me that timer 2 can only be used to create an interrupt from 1ms to 60ms is that right
eg???????

smxx

Joined: 18 Aug 2005
Posts: 188
Helped: 8
Location: iran(ahwaz)

17 Aug 2006 7:49 rpm counter

hi hameeds01
for this the easy way is use of multi task programing for 8051 (reel time operating system) RTO

swapgo

Joined: 24 Jun 2004
Posts: 127
Helped: 2

17 Aug 2006 11:16 Re: rpm counter

Just tie the RFID signal to an interrupt PIN and in the ISR measure the time diff betweem the two interrupts.

Based on this time we can find the RPM easily

mnoman

Joined: 26 Feb 2006
Posts: 10

18 Aug 2006 7:57 rpm counter

if i run a counter for 1sec then make it clear then after some time again run it to refresh the value may this work ?
do any one has code for that

smxx

Joined: 18 Aug 2005
Posts: 188
Helped: 8
Location: iran(ahwaz)

20 Aug 2006 13:58 rpm counter

hi mnoman
you use C or assmebly

blapcb

Joined: 07 Jan 2007
Posts: 67
Helped: 2

15 Jan 2007 2:26 Re: rpm counter

I think Hall Effect sensors are much better for this application, at least you can get ready products for it (like vehicle speed sensor etc.)

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mmokhrtar

Joined: 12 Sep 2007
Posts: 5

16 Sep 2007 8:27 rpm counter

can someone show me how to use the interupt for this RPM? im using hall effect sensor for my project.

i write program in basic.

nandhu015

Joined: 11 Feb 2006
Posts: 641
Helped: 46
Location: Tamilnadu, India

16 Sep 2007 17:50 Re: rpm counter

hi mmokhrtar

It is simple...

turn on the timer on first interrupt and turn the timer off at the second interrupt.

frequency = 1 / time

rpm = 60 * frequency

so you have rpm = 60 *(1/time)

that's all

Nandhu

alamaram

Joined: 20 Feb 2008
Posts: 1

20 Feb 2008 16:27 Re: rpm counter

can u give me the program for the counting the pulse outptut from the LM324 using 89C51. Reply as early as possible. send your replies to niranjansamuel(at)yahoo.com