BS2 Automotive Engine Data Collector

mrgadget

Hi All,

I have an old BS2 that I haven't played with in some time, and wonder if anyone has ever used one to collect auto engine data. RPM, temp, pressures etc. My idea goes quite deeper, eventually I want to send the data to a laptop to display a "virtual" dashboard using a VB6 program. It would be used on an old-school non-computerized engine (350 V8, carb). Any commercial equivalent seems to be based on ECU type engines and likely far out of price range anyways.

Items to monitor:
RPM
Head, manifold temp (both sides)
Oil Pressure/Temp
Alternator Volts/Amps
Intake Vacuum
Fuel Level (using factory fuel level system)

My first 3 questions:
Has anyone ventured into this,
Can the BS2 pump out data fast enough to maintain a relatively "real time" output,
Any suggestions on what sensors would be adequate?

Thanks,
Mike

steve_b

So, do you want to interface to a cars On-Board Diagnostics?
Most North American cars have something called OBD2. This is your car computer...it monitors a lot of the things you are interested in.

ELM electronics sells interface chips that allow you to put a stamp on one end and the other end to your computer....then ask and receive the data you are interested in.

I did purchase the ELM chip I needed to interface to my Jeep. I did get the recommended circuit built and tested....I "think" I actually got the stamp to talk to the chip as well (not that THAT was a big deal)....but I never did get around to getting it connected to the Jeep (was too cold at the time....and I "shelved" it and forgot it! -- like most projects! [noparse]:([/noparse]

Anyhow, I'm not sure it'd be real time....but it really depends on how you want to handle things. Do you want the Stamp to do some "number crunching"?

Certainly running your own sensors to every part of the vehicle and then having the stamp measure them one-by-one will take time (a couple of seconds for all of them) and then whatever calculations you need to do in order to display them correctly.....so real time in that case might be 5seconds.
An SX or better yet, a propellor, might be better suited to either speed (the SX) or multiple instructions (propellor).

Cheers

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<FONT>Steve



What's the best thing to do in a lightning storm? "take a one iron out the bag and hold it straight up above your head, even God cant hit a one iron!"
Lee Travino after the second time being hit by lightning!

Chris Savage

Mike,

This takes me back to a car I spent several months modifying after which my friends called it ‘Knight Rider’ referring to the TV show. Aside of monitoring several sensors the entire dashboard was completely replaced. Back to your question though…Back then I was using a Z80, however a BASIC Stamp 2 could accomplish the same thing. What I had was several sub-systems which handled the actual tasks of getting the data. The controller would then collect and compare the data, then display it on several displays.

The way I went about things though was to break each section down into a sub-system. For example, the Tach and Speedometer each had a counter circuit designed to count pulses for a specific duration and then latch that data and interrupt the controller. The controller would then fetch the data from the latch and reset the counter. Now, for the BASIC Stamp you could simply have a free-running counter that latches and waits for the BASIC Stamp to grab the data and reset the counter. The inherent delay of reading several latches and processing data would actually help to make the readings less jumpy.

I think on the analog circuits I had a latch system as well, except they were polled and so latched on the fly. The system had some nice features I wish were easier to implement into newer cars. Ah well…I hope this helps you some.

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Chris Savage
Parallax Tech Support