You can pick up a Lapdock 100 for around £50 – which for a mouse, keyboard, screen and battery combination is hard to beat. Naturally as its not a solution specifically for the Pi its not just plug and play. The Lapdock connectors consist of a HDMI micro plug and micro USB plug, so you’ll need to buy some adaptors and for best results be prepared to do some soldering. There are guides for building a Y cable all over the place many of varying quality from mediocre to poor (I did loose one that was really good – if I find it I’ll edit it in here!)
Apparently with later models of the Pi its a moot point but I found that any USB plugged into the (non power) USB sockets of the Pi would light the power led but not boot the Pi. Basically your Y cable should pass data +/- and GND to a usb DATA port and just GND and +5v to the Pi’s usb micro socket.
I found a great deal of conflicting information about the Lapdock 100 some people seemingly with the belief it simply could not be used with the Pi.
While there are some caveats I have found it to work just fine.
Make sure the config.txt is set correctly to make the HDMI active all the time.
You are better powering down without the mains lead in and in fact to get the Lapdock into a state where it will boot your Pi with the screen active (or at all) you must disconnect the Pi’s power connector and also the Lapdocks power.
Assuming both are disconnected or you were just running from battery (with the Pi’s power disconnected), you need to wait for the LED in on the Lapdocks “power button” to flash. If you’ve forgotten to unplug the power lead before shutting down (do it now) it could take 30 seconds or more after everything is disconnected. Running with just the battery when unplugging the Pi’s power it usually only takes 5 or 6 seconds to flash the LED (but sometimes longer)
Now the Lapdock is in the “post LED flash” condition one of two things will make the Lapdock power up the Pi and its display, either press the Lapdocks power button or plug in the Lapdocks power lead.
I’ll be adding a switch to the power side of the Y cable and be looking for a shorter HDMI cable – then with the addition of some velcro I should have quite a nice Pi Laptop.
As for the Lapdock itself the screen is really nice very clear and steady, the mouse is okay with the exception of the right mouse button (but I might have just got unlucky) – the keyboard itself is not the worlds best, especially the space bar which is quite poor sometimes registering two hits and sometimes none. Generally the feedback from the keys is not great, but it works!
So if its a dodgy low res LCD from Hong Kong or the Lapdock, I’d have to say the Lapdock has it.