i need help for measuring a speed of an object

Hi,

I want to design a circuit for measuring a speed of an object .

My approach is to use two IR sensors and the distance between them is fixed .
once the object passes the first sensor the time starts counting and when it passes the second sensor the time stops counting, the speed measured by speed=distance/time.

I can make this circuit using microcontroller easily but i need to build the circuit without using microcontrolles ?

Any help ?

thanks in advanced

hi,
One option is a multi-stage decimal counter driving LED display.
Use the two sensors for counter start/stop.
Use a known frequency clock for the counter.
This link shows a simple 1Hz counter.
https://www.electro-tech-online.com/blog-entries/basic-3-digit-led-decade-up-down-counter1.123/

E

This sounds like homework.

You will need to do three things.

1/ Measure the time interval over a known distance exactly as you suggest.

2/ Use the time interval number obtained to program the parallel input of a programmable frequency divider.
The output frequency from the divide by N counter will be the reciprocal of time , and output a frequency proportional to speed of the object.
What frequency you use to clock the divide by N counter input is up to you, but it provides an adjustable scaling factor to get the output in the speed units you want.

3/ Measure the output frequency of the divide by N counter using a frequency counter, which will then display the speed of the object in the correct units.

Steps one and two can use binary counters, but the frequency (speed) readout should obviously be decimal.

Hi,

It depends.
Mostely on the timing...t = s / v
But also size of object and route (precision) of movement
Is it a snail and the distance 1m
Or is it a car,
or is it a high velocity bullet and 5cm distance...

And what measurement resolution and accuracy do you expect?
What sensors?

Klaus

thanks guys

I am a power system student and i don't have enough experience in logic and electronics circuit

this project for instrumentation lab


is there any reference or book may be useful ?

regards

What are you measuring the speed of, a bullet or a snail ?