I have a dream...

[SETEC_Astronomy]

I would like to fully integrate a computer into my car. I already have the car and the computer but I have a few kinks to work out.
AUDIO
First I want to connect the computer to the car radio. The car radio is factory and has a tape deck and receiver. I first thought I was going to have an elaborate circuit to try to get audio into the radio but I have decided to use a cassette adapter instead. To avoid having a wire sticking out all of the time I will just open my radio and run the wire through it to behind the dash. I know this isn't ideal buts it's easy and I have owned the car for 3 years and have never once even attempted to listen to a cassette. Most of my decisions were based on wether or not I actually use something. I wanted to keep everything fully functional but if it only adds cost and complexity for something I don't even use what’s the point. The mic should be a no brainer I will just mount the mic near the drivers sun visor. I have hopes of using the mic to issue voice commands. I can program in Visual Basic and it has good tools for Text to speech and Voice recognition. I plan to put both to good use. Mercedes features on a KIA budget. What I need is a good circuit for a Line level converter so I can get audio into the computer from the car radio. If I’m already planning to open up the radio should I just try to tap the audio before it gets to the amplifier? Which would be better?

MISC
The keyboard I will just tuck under the seat when not in use. For mouse I plan to hack a regular mouse and use as a trackball or I will buy one premade. I may also use a laptop finger mouse. For the Serial, Parallel and USB ports I will use extensions so that I can access them easily.

POWER
This is where I have the most concerns and problems. How to power the computer? It seems silly to try to use an inverter to step up the voltage just to have the computer power supply knock it back down to 12V. I need the following voltages at the listed amperages:
3.3V ---- 6 Amps
5V ---- 10 Amps
5Vsb ---- .72 Amps
12V ---- 1.5 Amps
-12V ---- .2 Amps
The other issue is shutdown. I don’t want to have to wait for the computer to shut down every time I want to turn off my car. I need to design something that will automatically turn on the computer and produce power when I get in and turn the key. I also need something to leave the power going when I turn the car off to give the computer time to shut down, standby or hibernate. Any ideas on how this could be done? The computer doesn’t have buttons for anything but power. On the motherboard it lists where these switches would go but I can’t tell if this is one of those times where all the proper parts are there but no switch is present or if the motherboard is designed to have it but all of the parts are missing. The software does allow me to choose what action is taken when the power switch is pressed but is this seems like something that needs to be failsafe. Any ideas on this one? How bad is this going to stress the computer? I don’t make a lot of short trips, I go somewhere stay awhile and leave. So normally it won’t be off-on-off-on every five minutes but I am still wondering how well the computer will like this.

DRIVES
I plan to mount the hard drive and motherboard in the dash or someplace safe and out of the way with a sufficient amount of airflow to allow for proper cooling. The CD-ROM and 3.5" Floppy will likely go in the glove box or in a little cove under my radio. I like the accessability of it being under the radio but I don’t want my car to look like Frankensteins baby. I will probably end up tucking them away in the glove box or under the drivers seat.

DISPLAY
Last but not least I have the display issue. I already have a post concerning this but here it is anyway. I for obvious reasons don’t want a computer monitor sitting on my seat so I need to come up with something else. I can’t afford to go new so I will either need to modify an old laptop screen to fit my needs or get a cheap mini TV and display it that way. With TVs though the resolution is low compared to computer monitors as you all well know. How easy is it to use a laptop screen without the rest of it’s computer attached? Do laptop screens use a proprietary format or there a standard? I know some laptops have a connector for VGA but is that because that’s the format the laptop screen uses or is it there just so you have the option? I would use a laptop for the project but they aren’t as cheap, the parts are harder to find and they are generally slower (in my experience). Any ideas here?


Thanks to anyone who can help me with this project. I can’t wait to get it going and finished.

[Chris Smith]

For your steady voltages going towards shut down, I would use a box full of small motor cycle batteries. One for each voltage. These would have the amperage to let your computer do its shut down thing after the car is off, and that is about all.

The voltages them self at each battery can be regenerated using the standard 12 volts system, on the fly and running with the motor.

But to make things real easy, why not start with a lap top in the first place?

Especially for the screen.

They have one voltage usually around 18 to 22 volts at 5 amps or less.

[Robert Reed]

With all those voltages required, I think you would be better off with an inverter.It wont be any more inefficient than cobbling up a mess of low voltages and the iherent losses in doing so. Feed the inverter through a delay on "off" relay controlled by the ignition switch. Instant on , adjust off delay for a longer time than computer shutdown--1 minute? As to your audio running through the car radio-I don't get it. Wouln't a compact amplifier between mic an' 'pooter' do what you want, The line level required is probably only a volt or so--or am I missing something here.

[SETEC_Astronomy]

Chris: I would start with a laptop but like I mentioned the parts are more expensive and harder to come by. I like the idea of having PCI slots available to me among other features of a desktop computer.


Robert: I am not concerned with losses I am trying to avoid buying a $60 -$130 power inverter. You can find cheaper ones but they peak at 140 watts which just doesn't cut it. I had thought of the delay but I want to be able to ensure proper shutdown. What if the PC hangs and doesn't shut down within the time frame? I would have the power for the computer come from an always on circuit and then I would control the power outputs so that when the car is off and the computer has shut down I can "turn off" the regulators (or whatever I use). How much current would a computer that's hibernating or turned off use? Does the power supply completely shut down or does it simply stop powering certain devices? About the mic and audio: The mic will plug right into the computers audio card so that I can record my voice, make voice reminders, run voice recognition software, etc... . I want to be able to send audio to the car radio so I can also use the computer as an MP3 player. I could also watch movies if I have a screen and I way to play audio. My feeling is why add an audio amp and speakers when my car already has them. The getting audio from the radio might be unneeded but why not go all the way? I could then record radio broadcasts and have complete audio integration.


I did forget to add that I will ad a wireless networking card so that I can get net access on the go from wireless hotspots. My main reason for the wi-fi is so I can have my car parked at my house and if I am working on something in my car and I need to look something up I can access the net to do it. I can also share files between my computers. I could listen to any voice memos I made while in the car, I can get updates, control the car from inside my house ... The list is endless. I already have a homemade car alarm with remote start. I made my own circuits to have control of the windows, trunk release, climate control and all lights on the car. So from in my house I can turn on the car, roll up the windows, switch on the heat, set the blower to max and have the dome light on and waiting for me. I have so many ideas for this project I can go on and on. I have plans for GPS among other things. With the computer I can log all of my OBDII data and review it on my computer inside my house so that I don't have to sit in my car and look it over. I bought the OBDII reader from JPKNHTP. I got most of my other stuff from ebay. The computer I got free of charge from someone that was going to throw it out. I want this as cheap as I can get it since I don't have much money. When all is said and done I will have in my opinion the ultimate driving machine.

[JPKNHTP]

-JPKNHTP

[Chris Smith]

Unfortunately DC to DC power supplies are far more expensive than a UPS to run a computer.

http://www.amtrade.com/pc_power/switchi ... pplies.htm

The battery idea also gets complex as the 6 volts dropping to 5 volts
[+&-] at your amperages can cause a lot of heat.

Also keeping your 12 volts at 12 volts when the alternator is at 14.2 or higher is also a great loss.

Then having all the regulators for both in and out voltages will be a heater in it self which you can always use for the defrost cycle.

Invertors are probably the cheapest way because DC to DC Computer power supplies are $200 to $400.

Lap tops can be cheap but accessories are more expensive but they do make USB plug-ins like the PCI cards but again they are more expensive.

On the cheap probably isn’t going to happen no matter which way you try? Cheap, simple, or complex, either way you run into some brick walls.

Shut down modes are your least of worries. If the computer hangs, a power crash wont kill it.

[chopsuey]

There are websites dedicated to this topic, for one http://www.mp3car.com/. There are power supplies specifically made for "carputers" that will handle all the voltages, crank, shutdown, etc. You don't have to wait for the computer to shutdown the power supply will sense the car has been turned off and shutdown the computer gracefully. My coworker has an Opus power supply and while they are not cheap they work. He tried cheaper power supplies before and always had power problems. As far as the display goes I would look into a touchscreen on the website I mentioned earler. The Lilliput is popular and relatively cheap. It is sure nice to have a touchscreen in the car when you just want to skip a song, pulling out the keyboard/mouse is a pain. I would check out the website and browse the forums you will get some good ideas and advice.

[jollyrgr]

Okay, here is my buck fifty on the subject.

Use an AC inverter; safe, simple works. Use a UPS converted to full time use. A UPS is DESIGNED to power a computer. I have also powered computers using a standard voltage inverter found at the car accessory section of Wally World and automotive stores. These are cheap but not as cheap as the sometimes FREE UPS units. The DC computer power supplies are usually very expensive

Use MINI ATX computer or main board and a keyboard with integrated trackball.

You don't have an audio input jack for an iPOD or similar MP3 player so you want to go cassette input. I have fought with these for years and my latest battles (with GM decks) are that they don't always work. Forget modding the radio; it is likely not worth the effort. Instead get an FM modulator. There are a few types. Here is one that you insert inline with the antenna wire:

http://www.mp3playerstore.com/stuff_you ... /FM-02.htm

Simply power it on, tune to the station you set it to, and away you go.

They also sell wireless versions for a bit more money. But then you don't have to worry about installing anything; just turn it on and tune in. Here is one example:
http://www.ccrane.com/radios/fm-transmi ... itter.aspx

Forget the ones by Belkin and other companies that are about the size of a golf ball; they suck for car use. In a house setting they work fine. But then you can usually have wired inputs.

[SETEC_Astronomy]

What are the chances of me being able to build an inverter for around $20 or less? I have an extensive collection of transformers both large and small and I also have plenty of capacitors and other parts. Is this something that can be made from a very well stocked junk box?

[jollyrgr]

What are the chances of me being able to build an inverter for around $20 or less? I have an extensive collection of transformers both large and small and I also have plenty of capacitors and other parts. Is this something that can be made from a very well stocked junk box?

You might be able to do this for $20. But WHY? Spend $30 and get this: http://www.walmart.com/catalog/product. ... id=4891079 and you are DONE! How many watts do you expect your computer to be? If more than 300 watts, get a bigger inverter. The linked device has all sorts of protection built in, has already been designed, and is ready to go.

Even if you don't count your time into the project you are going to spend more on transistors, heat sinks, controllers, etc. just to get a 120V 60Hz signal without any safeguards.