First things first. I have ideas but almost no practical knowledge. That's what this post is for: asking anyone who can help to teach on how to implement the ideas on the next lines.
This is my scenario: I am married to a paraplegic BANNED and our car (a Chevrolet Zafira, same as Vauxhall 2005/2006 model) is fitted with some gear as a Bruno Curbsider wheelchair lift and a Guidosimplex brake/throttle lever. However, some things on the daily use are still impractical, and require quite some effort, such as having her mobile handy or the need to state she's entitled to the special parking spot. Due to human nature, people usually block them with a cone or a chain in my town, so it will be available to those who actually should park there.
As such, I thought of two hacks. A 5V power source embedded to the console and a lightbox fitted behind the accessibility sign sticker, both on the windshield and the rear glass, to make them more noticeable at night. And this being a BANNED's ride, it must be pretty, or at least not hideous.
EDIT: I just thought of using an EL white panel. That'd be neat and also less bulky.
I can build the box and use an original stock GM push button fitted to the console, but have got no idea on the electronic part. The stock button is a simple push type, attached to vehicular circuitry, such as the door lock servos, which means she would have to keep it pressed in order to keep the sign lit. Not good. I would like to get a "one touch on, one touch off" kind of thing, or, also, a timer circuit, that would light the sign up for, say, three minutes.
This, of course, would need power. As would the USB ports (or, directly, a 30 pin Apple connector, as she uses an iPhone. I even got a black cable to match the dashboard), so I thought of using a power source like this converter I found on Seeedstudio. I tripped on one step, though: how to limit current to each USB outlet and the sign backlight? I would like to have at least one port rated 5V @ 2A, and the others at 1A. And the circuitry must be kept slim and simple, as it will be embedded to the dashboard console.
So, the things I'm allegedly aware of are: a stable converter must be used to ensure quality power, almost everything can be done without a PCB circuit, and EM shielded cables are a wise choice. The things I need help with are: what should I use to limit current to the ports and feed the backlight, how to build the electronic part of the backlight (which resistors, kind of LEDs, the switcher/timer thing), recommended fuse ratings, and anything you can think of to make it feasible with simple parts, less prone to problems.
Any help would be greatly appreciated
(I still intend to install a 24V XLR connector in the trunk to top up the chair's batteries, but this is a low priority subject. And should be a simple one, right?)
