Help me to make an rpm counter using simple IR LED, detector and 89c51

[mnoman]

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]

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]

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]

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]

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]

rpm counter

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

 

[swapgo]

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]

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]

rpm counter

hi mnoman
you use C or assmebly

 

[blapcb]

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.)

 

[mmokhrtar]

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]

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]

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@yahoo.com

 

[madicalphy]

Re: rpm counter

frequency counter and led display of counts , for further information
**broken link removed**