In-car USB Hub
In-car USB Hub
Hi Guys,
I'm after installing a 4-port USB hub, but don't want a cigarette lighter powered one.
Does anyone have the technical savvy to suggest ways to power it (ie direct from car battery)?
Cheers
Paul.
I'm the first to admit I'm useless with this stuff, but from what I understand the cig lighter is essentially just a 12V power supply, so you could splice into the power cable of say the stereo instead? I'm not sure how much of a pain it would be to run power cables direct to the battery itself though
As Dave said, get a cig lighter powered one, cut off the plug and splice it in to any 12v source. Cig lighter and stereo are obvious ones in that area. You must also decide if you want a permanent supply, or one that is switched with the ignition. Running a cable direct to the battery is not hard, and is probably what I would do. If you remove the battery and plastic tray below it, there is a big grommet that goes directly through to the passenger footwell, with many wires through it already. This is also how you get power cables from the battery to amps in the car/boot. ALWAYS FIT A FUSE - somewhere on the +ive feed.
I am interested though... Why do you need a 4 port USB hub in your car?
You can chop down the 12v in two ways, using a very cheap method by using a 5v voltage regulator and a capacitor, this basically reduces the voltage by burning off what it doesn't need so generates a lot of heat. The othe method is to use an IC which requires a lot more components to create a circuit and is generally only for low power consumption devices (using 500mA). If you search the web there are circuit diagrams for what you need.
Like stoney says don't forget to fuse it. And you will need four 280ohm resistors across the USB connector or your device might not recognise that it is plugged in to a charging device.
The only reason I can think of is for charging - stereos don't support hubs as a rule.
Buy a cigarette lighter one, unscrew the cigarette lighter bit (they generally unscrew as they have an inline fuse in them) and run some wires from it onto the back of your cigarette lighter. Job jobbed.
toxo Buy a cigarette lighter one, unscrew the cigarette lighter bit (they generally unscrew as they have an inline fuse in them) and run some wires from it onto the back of your cigarette lighter. Job jobbed.
toxo Buy a cigarette lighter one, unscrew the cigarette lighter bit (they generally unscrew as they have an inline fuse in them) and run some wires from it onto the back of your cigarette lighter. Job jobbed.
Having a quick look on google you can find lots of circuit diagrams. The most popular voltage regulator is a 7805, which produces a 5V output, generally most produce a maximum current of 0.5A (which is what most cheap in-car chargers will use). I found that charging an Iphone you need to supply the phone with at least 0.75A, so a voltage regulator so I have used a 1A version.
The circuit diagram is very easy to follow and all you need is a couple of capacitors as shown below:
To connect to a USB socket, connect the +5V to pin 1, and 0V (or ground) to pin 4. You then need to connect four resistors to the other two pins. One from +5V to pin 2 and another from pin 2 to ground. Then do the same for pin 3 (one from +5V to pin 3 another from pin 3 to ground). I found that you probably don't need the reisitors for most devices, but my Iphone wouldn't recognise that it was plugged into a charging device without them.
If you do build these I would recomend using a heat skink attached to the voltage regulator as they get very hot when in use.
I hope this helps, but it is probably easier to buy some cheap car USB chargers, hack them up and install them where you want.
valo I hope this helps, but it is probably easier to buy some cheap car USB chargers, hack them up and install them where you want.
valo I hope this helps, but it is probably easier to buy some cheap car USB chargers, hack them up and install them where you want.