DC Motor Car Project

G. A. Basis = Why re-invent the wheel? Two other options I thought of 1) Window lift motor, Advantage: cheap, readily available Disadvantage: a lot of electronics to make work. From O. P. comment "What kind of switch?" probably beyond O. P.s ability. 2) Vacuum diaphragms from heater doors. Advantage: Same, Disadvantage, a lot of mechanical linkages, etc. -- JHF

Sounds like a fun project, but your starting point makes it look like you want a free ride and for someone else (many others) to do all the work for you.

First lesson in design is that there are usually many options, some rights and wrongs, but mostly constraints like, cost, size, availability of components, appearance and maintainability.

One design maxim is "keep it simple". Another is for failures to be "safe". I am not sure in your case whether this means "safe" because you can't see your GPS to steal it, or "safe" because you can still use it. That's the sort of decision that design is about and where good design is when you get it right.

The above implies that you probably won't use stepper motors and encoders - unless you have to. I can't see it in this case.

One simple design would be to not use electric motors at all but rather to use a damped spring raising mechanism and a press-to-release catch. If you do go to electric motors then I'd be looking at 1 motor via a worm gear arrangement (to give slow fairly constant speed) with a suitable forward-reverse, power on power off micro switch and relay system to make things happen.

As for motor size, just do some calculations of the moment involved and allow for friction and a safety factor, and look at the motor specs - stall torque in particular.

Now I could tell you how to do all that if I had the time to think it through, but that would be taking all the fun away, and really is probably not outside your ken.

Good luck

Check out some linear actuators here...http://www.firgelliauto.com/?gclid=CKzDpNHCzZ4CFQiA5QodMUCXsA

My suggestion should take you to a junk yard where you could explore to find a motorized hood motor or one which opens & closes the sliding door on a van. Bear in mind there could be a motor relay and a controller somewhere on the vehicle so you may need to make a few trips each time observing the make and model and the VIN helps you to determine the schematic and buy a booj for that car at Auto Zone or O'Rielly's, or Advance Auto or maybe better order a CD Auto Manual and it will guide you through the car. Once you determine if there are you should be able to determine if they are damaged or if you can access them and remove them yourself. We have a business in Montgomery Alabama that you go to and they will sale you a entire engine for less than $500 and you have to remove it yourself and that goes for anything of interest to you on one of their vehicles and they have foreign automobiles also. It is up to you to decide to buy new or to get what you can adapt to your need and adapting is much less expensive. As soon as I get some money I plan to go look myself at their inventory.

My friend had his GPS stolen but he was insured and his insurer ordered him a new one. Whatever you do it will not help much, his car was parked in a hospital parking lot with video surveillance cameras everywhere and the thief simply walked up threw a brick through the driver window and reached in the car and picked up his GPS and walked away. He did have a alarm system, it did work and no witnesses say this crime, why do hospital parking lots look so obvious to thieves? Get a $80.00 safe and install that to the car so you have to use a combination to get out your GPS, new phones will have GPS, or wait for a handheld GPS instead of a automotive one & just plug it in. Most junk yards have autos in them that are full of junk, I have seen such things as connectors for GPS but not a GPS unit yet, all the radios get removed and can be purchased inside the sales office.

Well, I think you should have another alternative.

I think American manufacturers are aiming at a legality issue, broodcasting rules & regulations affect the antenna style and for the better of styles are the European Antenna Style. This in Europe supports yep a different frequency band option which is not legalized in America. What we have in America is a fake Stereo while in Europe the broadcast is so different it is a true Stereo. Why is this - because their radio services are Digital Audio & Digital Video. Automobiles need to have a FM Wired Modulator Relay at the antenna. You can order FM Antenna kits that include the adapter and Modulator. See FM Antenna Adapters
FM Antenna Adapters
Installation Parts & Accessories
Digital Audio Broadcasting (DAB)
Digital Video Broadcasting (DVB)
MPEG-1, MPEG-2, skipping MPEG-3 & MPEG-4 Streams
Video and Audio processing fundamentals: Sampling, Quantizing, Coding, Multiplexing, Packetizing, Digital Filtering, Transforms, and Motion Compensation
MPEG-4 Streams are Video Object Types & their Coding, Mesh Coding, Animation, Scalability, Coding artifacts and More, MPEG streams can be multiplexed and transported.
MPEG-2 is the coding standard for DAB and DVB. MPEG-4 is more spectrum efficient than MPEG-2 and is flexible so it can be dynamically adjusted to different pipelines and different receiving terminals.
You see that iPhone developers have endorsed Firefow browser in their newest product but did they endorse the Digital Technology properly. NO not in America because there are laws against it in America for some reason broadcasters cannot develop radio to Digital but since the HDTV ban on Conventional Television we now see a fake Digital instead, its not as real as our European Radio Stations. A new member to MPEG Family Grouping is MPEG-X, like MPEG-7 that has metadata and content descriptions & MPEG-21 deals with content management. New MPEG Codecs are including additional profiles like ITU-T codec H26L.
The Radio Data System (RDS) Codes are not always the same in every European country while French Networks use PI Codes. You can get on CD-ROM The International Frequency List (IFL), published by The International Telecommunication Union (ITU). You can find information relating to frequency assignments maintained by the Radiocommunication Bureau (BR) in the Master International Frequency Register (MIFRE).
The European Broadcasting Union (EBU) once published complete lists of worldwide radio broadcasters but not since 199 when its monitoring station, Jurbise, was shutdown. You can still find EBU lists in handbooks but they are out of date. The European Broadcasting Union (EBU) is located in Geneva, Switzerland.
But the super difference is right now Digital HD Radio & The European HD Radio Alliance.
European HD Radio Alliance:
Fundamentally allows FM Multicasting which is the ability to broadcast multiple program streams over a single FM frequency (e.g. 97.7-1, 97.7-2, etc.)
> Static-free, crystal-clear reception
> FM sounds as sensational as CDs
> AM sounds as rich as analog FM stereo
> A variety of "data services," including text-based information - artist name, song title, weather alerts, school closings, etc. scrolled across your receiver display.
> Digital broadcasts in the same frequencies as analog broadcasts; listeners do not need to learn a new station number and today's stations remain at their current place on the dial
> Local content
> And its Free
HD Radio:
HD Radio technology enables AM and FM radio stations to broadcast their programs digitally – a tremendous technological leap from the analog broadcasts of the past.
HD Radio broadcasting is transforming the radio experience in ways never thought possible.
PRODUCTS:
Automotive:
Auto Companies Supporting HD Radio: Volvo, BMW, Jaguar, Ford, Hyundai, Mini, Mercury, Lincoln.

Auto Receivers:

JVC KD-AHD39
JVC KD-HDR1
JVC KD-HDR30
JVC KD-HDW10
JVC KT-HDP1
JVC KT-HD300 (Uses JVC bus to connect to head units, Compatible with Multiple JVC HD Radio-Ready head units, MSRP $109.95)
EUROPEAN HD RADIO ALLIANCE (EHDRA) MEMBERS
New and innovative features under development:
> Real-time traffic reports broadcast by local stations and visually displayed on a vehicle's navigation system
> Surround Sound> Store-and-Replay: Will allow listeners to rewind a song they just heard or record an entire program to play back at a more convenient listening time.
> On Demand Capabilities: Will give listeners instant access to news and information.
> "Buy" button: Will turn the radio into an interactive device for e-commerce, allowing for instant purchases of everything from concert tickets to advertised products.

Sounds very interesting!

I like the idea of using a photoelectric to determine your limits, but I would keep it simple and cheap. I would use a sanp action switch, Honeywell and numerous other companies make these. You can usually get these for less than five bucks each.

I would think you can get away with a reagular brushless motor with a gear on the shaft with a low RPM. You may be able to find a door that already has a 180 deg gear molded into it. I can see it my head, the older import cars used to have these for compartment doors.

To do your forward and reverse look for instructions on this, there should be several sites. All you'll need are a couple of DPDT relays and your limit switchs.

If you get stuck let me know, I'll try to point you in the right direction!

There are a number of car stereo models out there that have mechanicals that allow the radio face to flip in and out - why not cannibalize one of those?

Or better yet, find one that is GPS enabled, if available.