So, I finally got the female to female micro-HDMI coupler that I needed to complete my Motorola Atrix Laptop project. To recap, I purchased an Atrix Laptop dock (from Motorola) for my Raspberry Pi. The Raspberry Pi outputs video to either an HDMI cable (full size) or a crappy composite video connector (old-style RCA plug) and audio via headphone jack if using composite video. Since the dock accepts HDMI and USB, it should be fairly easy to mate these two together for some kind of frankentop device.
Know what? It was easy. Buuut…..getting the necessary connectors…well, that was quite the exercise.
Since both plugs on the dock were male, that meant I needed FEMALE couplers to plug the male cable into. Finding these was just terrible. Seems that they are very niche products and I had to order them both, one on eBay and one on Amazon.
First, the easy one…I just ordered the Atrix cable kit. That comes with the USB cable I needed. I ordered from Amazon.
The second, though, I went through eBay and that came from China. Took nearly three weeks to ship!
At any rate, I got all of the necessary connectors, cables, wire ties, shrink tubing, etc. to finish the job. Actually, just getting that damned micro-HDMI female coupler was the hardest part (and not burning my fingers with the soldering iron.)
NOTE: it is worth twisting the wires together and trying the cables first, before soldering. I did this to save myself any possible hassle should something not be right. However, when you solder them together, it is best NOT to twist them. Lay them in parallel and solder. Pre-tinning helps tremendously.
Since I wanted to use the lapdock to power the Pi AND take advantage of the keyboard and mouse pad, I had to Frankenstein the USB cables too. This is fairly easy: you want power only to the micro USB connector on the Pi, and DATA ONLY to the USB port on the Pi. So…I had to cut the ends off of a full size male USB cable and cut the Atrix USB cable in half. Carefully stripping away the outer tubing on each piece of cable, I then stripped the RED and BLACK wires on the female micro USB cable and the male micro-USB cable. These get some tubing before soldering. Once tubing is in place, carefully solder the wires. DON’T FORGET GROUND! Solder the ground wire as well.
Next, strip the WHITE and GREEN wires (the BLUE wire on the female side is not used here), place some tubing on each and solder. Next, pull the tubing over the expose wire, apply heat and set aside for a minute or two, the cable will be hot. I used a large piece of shrink tubing on the outside, but it did not cover the actually spliced area, so…embarrassingly, I used electrical tape where the three cable ends meet. It is not pretty, but it does not have to be pretty, just needs to work. I gave up my soldering days long ago, I pull the old iron out once in a while for repairs, not for looks.
Next, plug it all together and open the lid on the lapdock. If everything is ok, you will see your Pi booting on the gorgeous screen. Moto did a nice job selecting the screen, it looks great.
Now, after having used this set up for a few days, it is not all roses. My biggest complaint: the damned trackpad. It does not take much to make the mouse move and you can find yourself typing where you didn’t want. Also, shutting the lid will turn off and then turn on power to the Pi. Don’t know why, but it does. USB can be problematic: typing and using a WiFi adaptor seem to cause a problem: the keyboard will slow. WiFi is also interefered with by the USB hub built into the lapdock. Sometimes, it gets unresponsive, un plugging and plugging back in the WiFi adaptor seems to fix it.
These little quirks aside, this combo is pretty cool. My PiTop works pretty well and it was cheap: less than a hundred bucks for everything. And the Pi is just cool…no matter what one does with it.