... can't you just cut the coaxial plug and wire in your own "DC-connection" and fuse it? And as for the ignition switch, if it's hooked up to the right line, shouldn't it automatically turn off when the key is out?
"stop with the REINSTALLS, what do you think we got some lame-o installer!!!" - mitchjs
The additional features of the mp3car hub include a timer that keeps the hub on for a certain amount of time to allow you to stop at, say, a gas station without the USB devices going offline. The hub also solves many of the problems people have with USB devices that go missing when the system hibernates or sleeps.
And yes, you can wire up a timer relay to a powered hub and it will work. You can hack it all together if you want. The mp3car hub just does it in a nice package that works properly.
The voltage is the number one issue here.
Pumping 12 volts from the car into a USB device will fry it.
You need to give a hub 5 volts.
I agree that the $85 hub price is a bit ridiculous, but it saves a lot of the trouble found with other solutions and is much more rugged/reliable.
If you do want to go the cheaper route, get a hub with an external power supply. Cut the wire and feed 5 volts over the wire with the proper polarity. If ever confused about whats positive or negative, check it with a multimeter.
Ways to get 5 volts:
-12 volt to 5 volt "point of load" power supply.
---Converts 12 volts from the car into 5 volts for the usb hub
---This costs about $30.
-Using the 5 volt power supply that the computer already has.
--This costs whatever the length of wire from the computer to the USB hub will cost you
--Look at a hard drive connector from the computer's power supply. The red wire is positive 5 volts, the black wire closest to it is the negative wire for the 5 volt rail.
My Nearly Complete Car:
Micro Control Center... Control Your Car Across the Internet
Website: (It's a work in progress, really. All my projects have taken me from ever really developing it.)
I've got a cheap 5 port belkin hub which had a 5v socket but no adapter, cost about £4 ($7 or so) got the 5v from my M2-ATX- had zero issues.
Are you all still under the impression that you actually need a hub with a plug on it?
You all know USB is 4 wires. 2 of them are data which you don't touch. The other 2 are the 5v. Generally the red wire and then ground.
So why would you need to buy a 7 port hub with a plug and all? just buy a normal hub that has some wires, or buy some extension cables and splice the wires.
lol, that sounds like a lot more hassle than its worth! Considering a powered hub costs next to nothing and just requires a simple 5v feed...
yeah, well if you didnt want to wait around for a powered hub, and you already had another one I was saying.
Its not like the powered ones have any electronic components for the power, thats all. Its the same 5v.
Also, I think I saw someone say its 100ma? It should be known that this is true by specification but pretty much nothing follows the spec. Most systems have at least 500ma and many devices draw more.
500mA to 1A (1,000mA) USB loads are not uncommon - eg, GPS, external disks.
I've been meaning to check the "USB Spec" to see if it specifies "minimum" or maximum power per output (or load LOL) to be 500mA etc. Maybe next year....