Ardunino powered VW

Well everyone, I thought I'd share what I've been working on. I have a 1968 VW Beetle that I'm doing a whole lot of work to. One of the things is putting in an Arduino.

I have it hooked up to my Megajolt engine computer, LCD screen, GPS, RFID, (hopefully) soon to be bluetooth, iPod, other environmental sensors for automatic control of lights and such.

I have more info on my blog.

how do I find your blog?

it's linked in my first post but if that doesn't work, it http://efriesen.blogspot.com

au. watch out for your arduino... ;-)

im allways impressed by all the different applications people find for their arduinos... keep posting on your blog, and update here when exciting things happen, ill be dropping in now and then...

what will you be using the light and touch sensors for?

I will, right now I've got a bunch of stuff in the mail, just waiting to be worked on. The light sensor will be placed somewhere it can see daylight, and it will be used to turn the headlights on and off automatically in the dark. The touch sensor I have is this one. As you can see in the pictures, on the back it has a large solder pad. I'm thinking about putting something like poprivets into the fiberglass case I made, under the LCD screen, solder them to the touch sensor, and use them as buttons to control the iPod or other things.

Car electrical systems (especially old ones) can be very hostile environments.

You should have a series diode to protect against negative spikes from motors, relays, etc (any old 1N4000 series should do), and some arrangement like a varistor or a Zener+resistor to clip any positive spikes.

The series resistor used with the Zener can also reduce the heat dissipation of your voltage regulator (but will add a little extra "brown-out time" when the battery voltage drops during crank). Just pick a value that drops 3V or so at the maximum expected current.

Thanks Ran It's funny, I was reading a post buy you about this very thing yesterday. I need to pull my power supply out and do some mods, and what you've said will be included in them. I was planning on putting a 1N4007 inline with the supply, I'm not sure how you mean to arrange the Zener+resistor combo however.

You mention the Zener will add to the brown out time, I'd like to minimize this, preferable not have it at all. Actually, if I think about it, I'm planning on having two batteries, one for the starter, and the other for everything else. I could even put a small battery after the power supply to keep the Arduino running, as it wouldn't back feed because of the diode. Still though, I'm unclear of the Zener arrangement.

Thanks -Eric

It's not the Zener that adds to the brown-out time: it's the resistor. You put it in series with the incoming supply to reduce the current through the Zener when the voltage spikes (sorry about the lack of a schematic, but the only thing I have handy for drawing one is Eagle. I suppose I ought to figure out how to make it produce a .jpg or .png).

The impact during crank will probably be "insignificant" for your purposes, though: only a few extra mS as the voltage falls and rises due to the load of the starter. It doesn't matter to most folks, but I brought it up because it's one of those things you usually learn only from experience, and some find it a rather unpleasant surprise when they do.

Thanks again Ran
If you get a chance an Eagle file would do just fine.
Like I said before, I’d like the arduino to run constantly because the plan is to have a push button start that is controlled by the arduino to start the car. So for that to workit can’t brown out. So an extra battery will need to be in store for me I do believe

So I’ve completely changed my power supply, this one should be much better. I’ve also added bluetooth, but it doesn’t do anything yet, I still can’t program the Arduino (waiting for FTDI breakout board to arrive)