We’ve been really busy at work lately so not very much Raspberry Pi stuff has been happening. However this is too good to not blog about. I have managed to create a Raspberry Pi laptop and you can too. Here is how.
You may have seen the adverts for the Motorola Atrix phone. If you haven’t this is basically a mobile phone that can be docked into a laptop like shell and the phone provides all the processing power and display output. They call it a “lapdock”.
Cunningly, it is also possible to make this lapdock work for a Raspberry Pi. Credit is due to reddit user mathematical who pioneered this method and also to Veryevil (Steven Richardson) who posted about this on the Raspberry Pi forums. I have successfully repeated what they did, so this is proof it works.
a) 1 x Motorola Atrix Lapdock (try Amazon)
b) 1 x Micro HDMI Type D female to female adapter (try eBay)
c) 1 x Micro HDMI Type D male to HDMI 1.4 male cable (try Amazon)
d) 1 x Micro USB female to USB A female adapter cable (try eBay, note – these can be tricky to find one like this will also work)
e) 1 x Normal Micro USB cable (like you already use to power the Pi)
On the back of the Lapdock there is a slot that you’re supposed to connect the mobile phone into. It flips up. This slot has two male connectors that are designed to insert into the mobile phone when you dock it. One is for video (Micro HDMI) and the other for USB (Micro USB). Our objective here is to adapt this situation so we can connect the Pi to these connectors.
The easy part is for HDMI, take (b) and connect it to the lapdock. This now gives you a female socket on the other side which you can connect (c) to. The full HDMI end of (c) can then go straight into the Pi.
Now for USB. You’re going to need to do a bit of soldering. If you’re not comfortable doing this then try to get someone to help you. You need to make a Y shaped custom cable as per the wiring diagram above. First cut (e) in half and then take (d) and cut the USB A connector off. Strip back the wires carefully, these will be fine wires and you can often do it with just your fingernails.
The aim now is connect the power wires to the Micro USB end and the data wires to the USB-A end. The cable can then be used to both power the Pi and to connect the USB devices of the lapdock (e.g. keyboard, trackpad and extra USB ports). So this is just a matter of soldering the wires together as shown in the diagram. Note that the ground wires all need to join up and grey will actually be white. I recommend using either electrical tape or Heat Shrink Tubing to insulate the joins, obviously you should make it so that none of them can ever touch.
You should then end up with something like this;
Take the female micro USB end of your cable and connect it to the lapdock. The other two ends go into their respective connectors on the Pi and you should then be in business. The Pi will also detect USB devices that you plug into the two USB ports on the lapdock. Note that the lapdock needs to detect a HDMI connection before it will power up the Pi. So you can pull the HDMI connector out to turn off the power if desired.