magnetic pickup speed sensor in pune

[csr1981]

A magnetic pickup unit is being used as engine speed sensor. How it can be interfaced to PIC micrcontroller for sensing the engine speed and display on LCD.

Can anybody please provide the logic/code.

 

[ScOe]

Re: Engine Speed Sensing

It is probably hall effect sensor. It will give impuls when it detect gear teeth or something. So you need to know how many impuls you will get in one revolution, also if you dont measure output shaft rotations, you need to include gear ratio.

There are few types of hall sensors, one type will induce voltage when they detect change in magnetic field. It only has two pins. Mostly used on bycicle speedometers. So basically you need to provide voltage on sensor pins and on positive end put one resistor and connect to uC interrupt pin and detect falling edge for every impulse. Than you need to meassure time between two pulses and you can calculate freq of the pulses. From that you can easily calculate rpm.
To calculate speed, you need to have rpm of output shaft and diametar of wheel
v=w*r [m/s] where w is rotational speed [1/s], and r is radius of the wheel in [m].
So speed is v=(rpm/60)*r

I cant provide any code cause i havent use PIC for a long time, so i kindda forgot syntax