Electronics apple keyboard usb hub power

[notatoad]

i got a shiny new apple alu keyboard today, and it's a joy to type on. it also has 2 very convenient USB 2.0 ports on the sides, but the manual says that those ports will only power devices that draw a lot of power (like my mp3 player) when it's plugged into an iMac. does anybody know how the imac gives the keyboard it's extra power, and if it would be possible to rig up some sort of supplementary power adapter for the keyboard so that i could charge my mp3 player and phone through the keyboard hub? i've got an adjustable voltage wall-wart just waiting to be hacked up .

[lost_modder]

ok i have no idea how the iMac gives more power. but, i can say that it's no problem to mod it for more. start by removing power from the side usb by cutting the red wire (+5v) and the black wire (ground) or by cutting circuit traces to pins 1 & 4 on the usb. depending how it's actually connected. then set your wall supply to 5v & connect the positive to pin 1 (where red wire was) and the ground to pin 4 (where black wire was). usb is only rated to 500ma, so any device (mp3 player, etc) should never need more than that. so a crazy big power supply is not needed. or really recommended. good luck!

[Langer]

The slim apple board USB gives very little power in my experience as well - anything more than a mouse and it throws up power errors.

[notatoad]

thanks lost_modder. that's a nice simple solution.

[tranc3]

not sure if it'll work but i was thinking use his idea, but instead of a wall out lit you could use a second usb on the computer to get more power? in theory it should work similar to how external hdd (usb 2.0) use a second usb to power the drive and one for data.

[Nexxo]

Originally Posted by supertoad

i got a shiny new apple alu keyboard today, and it's a joy to type on. it also has 2 very convenient USB 2.0 ports on the sides, but the manual says that those ports will only power devices that draw a lot of power (like my mp3 player) when it's plugged into an iMac. does anybody know how the imac gives the keyboard it's extra power, and if it would be possible to rig up some sort of supplementary power adapter for the keyboard so that i could charge my mp3 player and phone through the keyboard hub? i've got an adjustable voltage wall-wart just waiting to be hacked up .

Normally, a USB port's power output is rated at 5V, 0.5A, which is not much juice. Apple, being the proprietary guys that they are, have uprated the USB power output of the iMac (and incidentally, the Macbook Air) to probably double the Amps.

If you want to do that on a PC, as lost_modder says you have to cut the red and black wire on the USB port and hook them to the 5V line of your PSU instead. A bit cumbersome, but it should work.

[nitrous9200]

I set up an iMac for a customer and had huge problems with USB power, he had 8 different things: printer, scanner, Stamps.com scale, card scanner, SD card reader, external hard drive, Apple keyboard and mouse. The printer and KB/mouse were plugged into two of the iMac's onboard ports, and a powered hub was plugged into the 3rd holding all of the other devices. I don't know how I got everything to work, but I think I did. Not sure if it has to do anything with this. PS I hate the new alu keyboard; maybe if I got used to it I'd like it a bit more