RPM counter using 8051

Hi all,

I’m trying to do RPM counter project using 8051. Everything is works fine with 555-Timer output and DAC pulses but when I give the motor rotation pulses from sensor, the RPM count value is oscillating in different values. Details are as below

  1. I’m using counter for counting pulses and Timer for one second delay.

  2. every one second delay I’m displaying count value and assigning it back to zero.

  3. I’m multiplying it by 60 for RPM and displaying the result value in 7-segment display.

Need help Friends…