Here are some pictures for the cable hack necessary to get the Raspberry Pi and the LapDock to work together.
The cable mod consists of a male USB microB plug, female USB microB plug, and a male USB A plug. I got a USB micro extension wire(microB male on one end, microB female on the other) and just a USB A wire(that I cut) and I exposed and separated the 4 wires. I plugged them into the Raspberry Pi so I can make any adjustments to length;
NOTE: the black micro HDMI cable in the middle of the picture served as the final length of the cable hack(so the modded cable isn’t uneven to the micro HDMI extension cable.
On the black male microB cable, only the power cable(red+black) are used, so the other cables are folded and taped to the wire body.
On the white male A cable, only the RED wire is folded and taped away.
The thing is that the ground wire(black) needs to be connected to all 3 plugs.
- The red wire from the black male microB is soldered to the red wire from the black female microB.
- The green wire from the white male A cable is soldered to the green wire on the black female microB cable.
- The white wire from the white male A cable is soldered to the white wire on the black female microB cable.
- The black wire(ground) from the black male microB is soldered to both the black wire from the white male A cable and to the black wire from the female microB cable.
Finally this is all wrapped up in duct tape to get this:
The bottom line is… the lapdock’s male microB cable provides power AND the data from the keyboard+trackpad. What this cable does is separate that into 2 cables – one that outputs power, and one that outputs the data coming from the keyboard+trackpad.
It was a quick job and I like the result!