Tachometer

[evolive]

Hello,

I plan on building a small digital tachometer and I have all these ideas but don't know what is best.

I have been researching about PIC and they are quite popular. I've had some experience with the 68HC11 and I have a evaluation board that I can try my project on.

I'm wondering if I should go ahead and write a software for it or just do the whole logic gate stuff?

I plan on using a hall-effect that sends pulses to a frequency to voltage converter. That voltage will then be multiplied (using a dip switch) in the PIC and the output will be displayed on an LCD or four 7-segment displays.

So the idea is that I need chip that will allow me to have 2 inputs and 1 output and programmable.

So should I stick to my 68HC11 or can anyone suggest a PIC with a GOOD book on how to configure the I/O ports.

btw... this tachometer will be mounted on a solar boat which will be competiting at www.solarsplash.com

Thank you.

 

[Sebi]

The frequency counting is more accurate method, and not a difficult work for PIC.

 

[gtrman1992]

PIC is a very nice processor, but if you have the eval board for the HC11 why not use that. The project is small so it is much of a muchness.

 

[evolive]

i've been searching on the net and can't find (yet) anyone who has codes for this project. how do i program my chip to read frequency?

thanx

 

[bmcculla]

Most microcontrollers will let you use an external signal as the clock input for their timer. As long as you have more than one timer you can use one to count the pulses on the external pin and one to time the time interval that you're counting over.

You could also just poll an input pin looking for a change from 0 to 1 of the input pulse. If you count these transitions you can get the pulses per second.

Brent

 

[absolution]

personally i dont like programming too much stuff if i dont have to. i would suggest using a frequency to voltage converter and using a DVM chip to do the rest. there was another such posting for a speedometer and that would do basically the same thing and some guy suggested using a LM2917 which will do your frequency to voltage and us a 7107 as ur DVM. :twisted: