SparkFun Forums

[nicolasronan]

Hello
is it possible to logger pulse from a tachometer (RPM)?
may be with a converter frequency to volt (LM2917)!
http://www.national.com/mpf/LM/LM2917.html

and

how to view data on a graph ? a software? an example?

thank you
Ronan

sorry for my english[/url]

[PhatBob]

If you just want to count RPM speed that will work to an extent.
If you want greater accuracy then you need to work with something like the LM1815 which will generate interupts for you to time.

Rob

[nicolasronan]

thank you for your answer
i want log a rpm signal from a tachometer. the signal is a square wave :
0 to 5 volt and frequency 0 to 200hz.

do you have an idea ?

[nicolasronan]

up please

[ijm51000]

Hi,

I am looking at the same sort of idea, 100hz is my frequency, this product seems ideal for this type of project.

I have come to the following outline for the project.

1. Instead of analog reprogram a port to interrupt driven digital.
2. count the pulses over a given time period and calculate average rpm
3. convert average rpm to an ascii string
4. log to device with time stamp - though time stamp is not a big requirement

I am just not sure where to start, lack of experience in programming these devices, actually no experience.

I have used the Arduino and doing the interrupt driven rpm count is easy and can be sent via usb to my computer, but I a stand alone device. The Arduino has been interfaced with SD cards, but its an additional board, the logomatic has the advantage of being a single board solution.

Cheers

Ian