"Raceduino" project concept (Tons of I/O

Hi all just wanted to see if I could get some fresh eyes on my first (big) Arduino-based project. I'm looking to be able to control everything in my race car from one location and have data logging features, etc.

Presenting the Raceduino:

http://racetronics.blogspot.com/p/raceduino.html

I'm looking for suggestions on hardware to use for any of the features, the only big thing I've invested in to this point is the Kent Display (still open to suggestions on a large display though!).

One big thing is the controller board, since I'm looking at needing a ton of I/O I was thinking of possibly using Seeedstudio's Mega instead of the plain one:

http://www.seeedstudio.com/depot/seeeduino-mega-fully-assembled-p-438.html?cPath=27

Hopefully I've presented it well enough for non-car guys to understand as well :-/

Thanks for taking a look!

It looks like a great project, I also drag race (motorcycles). Post a link to some pictures of your car if you have them.

Sorry I don't know much about Arduino as such, but that's a sh*t load of IO you need there. I started counting and very quickly passed the 70 IOs the Seeduino has, so I don't see it working out of the box. You're going to have to do some multiplexing, use SIPO shift registers, IO expanders, IO expansion shields or something.

For example your practice tree doesn't need 30 IO lines, you could do it with three.

One thing that worries me though is all this IO being run around a vehicle with presumably no ESD protection. That could be a good way to blow things up.

Thanks for the replies!

For example your practice tree doesn't need 30 IO lines, you could do it with three.

Yes, I've been discovering that, I didn't realize you can cascade the 74HC595 shift register! I just ordered two 5 packs!

no ESD protection

Is there something I can/should do about this? I am running a lot of wires around in a stripped down race car although all modern cars are wired beyond belief compared to what I'm planning :P

Post a link to some pictures of your car if you have them.

I can do ya one better! Video: http://www.youtube.com/watch?v=UtatkjDyDz8

Pictures: http://racetronics.blogspot.com/p/stuff-page.html

I also drag race (motorcycles).

You've got guts man! /salute!

Is there something I can/should do about this? I am running a lot of wires around in a stripped down race car although all modern cars are wired beyond belief compared to what I'm planning

You main issues will likely be voltage spikes from the car's electrical system, and noise. I know I have seen a paper or two floating around on this forum (IIRC, it was a link to an app sheet by Atmel) regarding dealing with potential spikes; if you don't take care of them, you'll likely fry your hardware (microcontroller, display, etc) eventually.

As far as signals and noise go, your main concern will be those running from sensors to the controller. You can take care of a lot of noise with capacitors (and depending on the noise, coils), but you also need to think about shielding the wires, perhaps with flexible steel braid running from the sensor to the controller. If you are connected to the cars electrical system (which I think will be most likely), your common ground will be the chassis, so make sure that you ground the steel braid on both ends to the chassis ground as well.

Thanks for the tips cr0sh! I haven't planned out much for the final install into the car yet, but I do have a vague idea of keeping it as isolated from the car's wiring as possible. Most of the devices will be controlled via relays (they're almost all simply on/off just at the right time ;) ), the Air/Fuel ratio and the speed sensors are the only places where that will be tough I think.

The way I have wired up the rest of the car it is designed to pull as little power as possible (it didn't even have an alternator for a while). I've actually been considering using some sort of rechargeable power supply for the Arduino that is completely independent of the car (unless I flip a "charge" switch of some kind). This is all in the distant future however since my mustang is back in the U.S. so for my stage 1 design I'll be putting the display, data logging and accelerometer together to take to the road course in my 924 :P

Have a look at this http://www.megamanual.com/ms2/pcb.htm

It's an ECU, this page has full schematics and it's interesting to see how they've conditioned the IO and PSU.

At first glance it looks a bit over complicated, but I gather it's a popular product so presumably works.

Shift registers would help a lot in this case. But, make sure you have an abstraction for them (or write one yourself), don't write bad code.

Thanks for the link Greynomad! I'd heard of MegaSquirt somewhere before, didn't know much about it though.

don't write bad code

I'll try not to Poincare, I'll be posting a lot of it on here for suggestions ;) gotta love a big open-source community!