Any Electrical People Out There?

[scsinet]

Originally Posted by juice_1080
http:///forum/post/2595918
I am wondering if I can just bypass the weird idea of going from the car's DC source to an inverter (AC) and then back to DC again.

Originally Posted by juice_1080
http:///forum/post/2597149
I really want to avoid trying to find a place to permanently hide a power inverter.

Originally Posted by juice_1080
http:///forum/post/2597140
I know there are some Hard Drives like the WD Passport that run entirely off the USB drive (including power) but I am not sure if that CD player would have enough power to run it. Otherwise that would be the best bet.

No, I'm not "insulted." It's irrelevant anyway because I didn't spend any time designing anything. I pointed him to a datasheet on a semiconductor and spent 5 seconds making a drawing in paint.
What I am is curious why you brought up points that had been repeatedly covered earlier in the thread.
FWIW, I'd use a power inverter if I were trying to do this - so I agree with the inverter idea. As you said, he was asking for alternatives... to an inverter. But if he wants to do it a different way, and I know a different way, I'm going to present it. Being the type of person I am, where cost is secondary to the fun of a challenging project, I can certainly relate to someone who wants to have at it.
And yes, you adjust the output voltage with a pot. Is that some kind of problem?
Originally Posted by bionicarm
By the time he gets all the components, a good soldering iron, and a decent voltmeter, he could buy the plug-in inverter for half the price.
Again, did you actually read the thread....
Originally Posted by juice_1080
I have my electronics kit from classes (breadboards, tools, multimeter, etc.)

No, I do not get insulted by alternate suggestions, nor would I ever wish to come across as saying that "my way is the only way" or anything like that, and I certainly do not want to chase a new member away from the boards. I am only saying read the thread.

 

[stdreb27]

Originally Posted by bionicarm
http:///forum/post/2598116
Kind of curious why you want to design an electrical circuit for a hard drive, when the technology is already out there. They make power inverters now that plug into the 12v power outlets (also known as cigarette lighters) that are in most cars these days. The unit is only around 4 inches long, and has one or two AC plugs on the end of it. Do a search for Xantrex Technologies XPower Micro 175-Watt Inverter #851-0178. It's only $26.
As far as the hard drive, you can find all kinds of self-contained external hards drives that already have the 120v to 12v circuitry built into them. Costco, Wallyworld, Newegg all sell them. Here's a 320GB for $75 -
Kaser StorageVault 320GB USB 2.0 External Hard Drive (Black)
How are you connecting this hard drive to your car's stereo head unit? Unless you have some USB input into your car's head unit, you'd have to tear it open and mess with the circuitry. Cheaper just to buy an 32GB Ipod and an FM Transmitter unit.
If you want to get real fancy, do a search for CarPC. For around $700, they have complete PC's with small LCD screens that you can install into your car. They come with adapters to hook the system directly to your car's 12V system so that it turns on when you turn on your car. For another $75, you can get an InDashPC unit that is compatible with almost any make of car. This device allows you to hook a CarPC directly into your car's audio system so you don't have to buy and external amplifier.
Ever just want to try and build something? There is a feeling of euphoria, (and it is really good when most of the stuff you build doesn't work) when you build something and it works. Personally I'd just do the inverter myself. But you don't have to be mean to scsinet he is very informed when he posts.

 

[juice_1080]

Ok, I guess I will straighten this out.
First off the CD player DOES have a USB port on it and will accept up to a 250GB HD. It was never my intent to tear apart a brand new CD Player. I would be just taking one of the 20 USB cables that are sitting in my drawer useless to splice into if I went that route.
Second there would be a couple reasons I am doing this: Since I can remember I have loved to take things apart/fix things/make things so to me this would be fun and a good learning experience. I have just about everything I need but the LM338 at my disposal (soldering iron, resistors, caps, pots, etc) and all I would need to buy is it and an in-line fuse holder.
Third I only have one cigar outlet and being that I am a delivery driver and need my phone charged at all times for when people give the wrong addresses (happens a couple times nightly) that outlet is dedicated to the phone charger.
Lastly SCSInet is trying to help me with what I asked for....an alternative to a power inverter....not the suggestion to use the inverter.
This was in no way shape or form intended to bash anybody or start a fight....just simply clearing things up.

 

[bionicarm]

Sorry for starting a controversy. Sounds like you have what you need. I've actually built and designed circuits similar to this back in the 80's (I'm an Electrical Engineer). I installed a small 'computer' for the same reason into one of my cars back in the 90's. It ran Linux, and I interfaced it with my car stereo for the same reasons you're trying to do. The only reason I gave you the alternatives is because with the way technology is today, I don't like reinventing the wheel. Like I said, I just bought a small power inverter that plugs into my cigar outlet that has both an AC plug, and another cigar outlet on the front of the device. So I have a plug to use for any AC device, and I still have a cigar outlet to plug in my phone charger.
Enjoy the circuit build. Go to Radio Shack and pick you up one of those white breadboards for testing and designing circuits like the one you want to build. It has all the holes in it you need to plug in all your components. You can then get some 18 gauge wire to make your circuit connections. You can do all your testing without doing any soldering. I've even left my 'build' on these breadboards and installed it into a case to use as the actual finished product. I'd still buy one of those 320GB enclosed drives, then install your circuit into that. You could mount a molex plug somewhere on the back to connect your 12V positive and ground to, that will go to your battery or key circuitry. Better yet, splice into the 12V powering your car's stereo head unit. Then the drive will come on at the same time your radio does. You can make a 'harness' that holds the two wires for the power and your USB cable that goes from the drive enclosure to your head unit. Run them under the carpet to a place under your passenger seat. You can store the drive under there, and plug/unplug when you need to refresh your tunes.

 

[salty blues]

Originally Posted by bionicarm
http:///forum/post/2598245
Is there a reason why you're taking an offense to my post? I'm glad you gave him the suggestion you did, but he was asking for alternatives. Are you insulted that current technology already has what he wants available, and he won't use your electrical design that you spent so much time putting together? You're wanting him to hack into a hard drive case to install this little circuit of yours, even "shaving into the USB cable to expose the wires"? The wire on a USB cable is very small. Unless you've done a lot of electrical soldering, all you're going to do is destroy a good cable, especially if you don't have the right soldering iron. And you want him to tweak the 5V with a pot? By the time he gets all the components, a good soldering iron, and a decent voltmeter, he could buy the plug-in inverter for half the price.
I never read anywhere where he stated his head unit had a USB port. Unless your car is only a couple years old, the factory unit doesn't come with one. He says he only has one power outlet. I just bought an inverter that plugs into a lighter that has one AC outlet, and then another 12V power outlet in the front. A hard drive in a case doesn't draw that much power. Your 12V system will have no problems handling the current draw. On long trips, I run two power inverters that drive two laptops, a DVD player, and a PS3.
Don't feel too bad. I suggested an inverter and got dusted up too. Tail is properly tucked between my legs as I yelp into the distance. >>>>>>>>>>>>>>>>>>>>