You can get engine RPM from the OBD-2 (on board diagnostic) port on 1996
model year and later vehicles.
You have to talk the correct OBD-2 protocol for your vehicle.  It isn't as
straight forward as other methods, but it works great.  You can get digital
updates (from the vehicle's ECU) of the RPM about 10 times per second.

Just a thought...

Gary

-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Josh Koffman
Sent: Tuesday, July 15, 2003 5:05 PM
To: PICLIST@MITVMA.MIT.EDU
Subject: [OT]: Car Tach designs


Hi All. I'm considering putting a tachometer in my truck (it's not a
diesel, don't worry). I've been searching the archives and I've seen
mention of a few designs, but haven't found any working links. Closest
I've come is mention of tacho.pdf on Tony Nixon's site that's gone. I
seem to remember Neil (picdude) talking about one before. Any links?

Thanks,

Josh
--
A common mistake that people make when trying to design something
completely foolproof is to underestimate the ingenuity of complete
fools.
        -Douglas Adams

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics