Keeping the GPS Powered

Anshu · 03-24-2006, 03:27 PM

I just had a quick question. Ive searched around and managed to find some good information on keeping the gps(BU 353) powered via the car all the time so it keeps the lock. My plan was to hack up a usb exstension so I keep the actual units cord in good condition. My only quick question was which regulator do i need, from radioshack? I know I need a 12v to 5v, but I couldnt find one online. Also do i just take the power from the regulator and ground it to the chassis or do i have to run the line back to the regulator and ground the regulator?
Cheers

amthar · 03-24-2006, 03:49 PM

USB uses 5v. I would pick up a 5V PoL (like the ones they sell on mp3car.com) and run it off of that.

Wiredwrx · 03-24-2006, 04:55 PM

Quote: Originally Posted by amthar

USB uses 5v. I would pick up a 5V PoL (like the ones they sell on mp3car.com) and run it off of that.

But, you can use a 7805 (I think Ratshack has them) Make sure you have appropriate cooling on the 7805. I would use an LM338K instead. It is variable, so you will have to tinker a little, but it has a 3 amp output, which means, since you are only drawing 1/2 an amp, that it will stay cooler, easier. You can then also use it to power another USB device or 2 if you like, just keep the cooling in mind.

Cris · 03-24-2006, 05:34 PM

Quote: Originally Posted by amthar

USB uses 5v. I would pick up a 5V PoL (like the ones they sell on mp3car.com) and run it off of that.

Anshu · 03-24-2006, 06:46 PM

any good links or anything on actually cutting up and working with the usb cable?

Anshu · 03-24-2006, 08:08 PM

can someone verify this diagram for me?

Cheers

Wiredwrx · 03-24-2006, 08:38 PM

Quote: Originally Posted by Anshu

can someone verify this diagram for me?

Cheers

Not 100 percent correct.

The ground on the 7805 and the Tab are the same. You can use one or the other. There is no need to run the usb ground to there, you can leave the USB grounded on the MB if you want, or you can ground it to the car directly. In general, people do not ground the devide being powered through the Regulator. I am not sure if that is because that can be problematic, or just because it is not done that way, though since the tab and the ground are connected, there is technically nothing wrong with it.

Michael

Anshu · 03-24-2006, 08:54 PM

interesting,the simplest way then is of course to just leave it as, but thats weird doesnt charge then build up in the computer itself? or can it flow out via its neg(ground) wires?

Wiredwrx · 03-25-2006, 01:17 AM

Quote: Originally Posted by Anshu

interesting,the simplest way then is of course to just leave it as, but thats weird doesnt charge then build up in the computer itself? or can it flow out via its neg(ground) wires?

It will ground the way the USB is grounded, which is probably to the battery. There is no such thing as buildup.

Michael

Anshu · 03-25-2006, 01:22 AM

thanks for the help. i was just thinking of physics and how the electrons have to get back to the battery to keep the circuit flowing. But i suppose they will in the laptop.

Anshu · 03-25-2006, 02:02 AM

uh oh.
So i took out the red wire(5v+) a little bit by clipping it at the connector(or very close) and then going about 3 inches back and striping the insulation and pulling the wire through. I then taped and heatshrinked everything. But if i plug the modified plug into the usb hub the entire hub shuts off. Im sorta woried whats going to happen if i plug it into the computer itself.
Is it just because there isnt coninuity in the wires? The 5vdc is just lying in the air, not touching anything.

Anshu · 03-25-2006, 02:32 PM

anyone?

Wiredwrx · 03-25-2006, 05:05 PM

Quote: Originally Posted by Anshu

anyone?

That doesn't make sense.

Why did you pick the red wire?? Did you check continuity to make sure the red wire is the wire you wanted. While there might be a "standard" color for the usb wire, there is no guarantee the company will follow it. Make sure you have the right wire.

Check this out http://pinouts.ru/data/USB_pinout.shtml

Michael

god_of_cpu · 03-25-2006, 05:17 PM

Quote: Originally Posted by Anshu

I just had a quick question. Ive searched around and managed to find some good information on keeping the gps(BU 353) powered via the car all the time so it keeps the lock. My plan was to hack up a usb exstension so I keep the actual units cord in good condition. My only quick question was which regulator do i need, from radioshack? I know I need a 12v to 5v, but I couldnt find one online. Also do i just take the power from the regulator and ground it to the chassis or do i have to run the line back to the regulator and ground the regulator?
Cheers

Why do you even need to do this? I've never had a problem with the BU535 not having a lock by the time the computer resumes from hibernation.

Anshu · 03-25-2006, 09:09 PM

Ok, sorry for not getting back to yall. Red was the power wire, and like a fool I had not taped up the end near the connector, so it was touching the connector and hence grounding out. I fixed that.

The real issue that I want to point out is that after 1 hr of trouble shooting, I found out that if you power the GPS Externally, then you have to have it grounded aswell. So I was a little frustrated when that made the thing start blinking.
Oh well
Cheers