Monday, November 18, 2013


OK, this is sort of a rough thing to admit - but I have a lot of extra tablets lying around.

So, hear me out - first, I'm a CTO and so I wind up buying a lot of them for experimentation, plus they also sort of show up when you buy things these days. I purchased a new TV a few months ago, and...poof, tablet. Then, of course, there's the actual tablets that I use in my personal life.

The problem with tablet proliferation is: they are all really pretty nice, so you don't want to get rid of them - but as technology moves on, the older ones get left by the wayside. Either the operating system doesn't upgrade any further, or the hardware can't support the new operating systems. The two tablets I'm going to talk about fall into those last two categories: The Samsung Galaxy Tab 7+ and the Asus Transformer Prime.

The Hardware

The Galaxy Tab 7+ is one of the best tablets I've ever owned - seriously, I have no idea why Samsung messed with that tablet line as badly as they have, but the new Galaxy 7 series just doesn't do it for me. This thing had everything, a blazingly fast dual core CPU (before it was fashionable to have quad cores), expandable memory, front/back cameras, excellent wifi, and on and on.

Unfortunately, the 7+ is stuck on Android 4.0.x, and doesn't look like it's going to be updated any further. Pity, but... it's time for a new life.

The Asus Transformer Prime is another sad little character in the world of tablets. Although blazingly fast (and gorgeous) when it came out, it was soon plagued by issues relating to it's wifi and GPS. (Both radios were getting partially blocked by that snazzy metal case.) In addition, the unit only has 1G of system RAM - so as the Android world moved to Ice Cream Sandwich and beyond, even though the Transformer Prime was getting the updates, it was slowing way way down for practical use.

It's sad, because the screen was really phenomenal, it too will get a second life.

For years I've wanted a kitchen computer (anyone remember Audrey?) - but they were always too large, too unreliable, and too difficult to install cleanly. Pre-iPad tablet computers existed, but they were extremely expensive and prone to overheating. Plus, they really couldn't do much in the way of home automation.

Enter 2013: tablets are plentiful (and lying around my home office, apparently), and home automation has seen a resurgence (Nest, Sonos, Media Center, alarm systems, etc.) - this seemed to be the perfect opportunity to use what I had to create a low-cost JARVIS for my house. One "JARVIS" would be in my bedroom (the Tab 7+) and the other would be in my kitchen (the Asus). This would allow me to experiment with different configurations and interoperability between the two units, and see what sort of additional kick to my home automation I could provide.

The Software

In order for these things to become "JARVIS," they had to have the right look. The naked Android interface wouldn't cut it, plus placing widgets all over the screen would get pretty clumsy and cluttered over time. I was looking for an interface that would suggest "JARVIS," but allow me quick access to all of the applications I know I wanted in both my kitchen and my bedroom: Sonos, Media Center controls, Recipes, Weather, and a few others. Not a ton of things, just those that were useful.

Fortunately, this is Android, and adapting the screen to my needs was just a matter of replacing the home screen launcher. I sat down for several hours and looked at all of my alternatives, and the one that made the most sense was GinLemon's Smart Launcher Pro. SL has the interface I was looking for (a circular flower of large buttons for the apps, plus a clock and date in constant display) and it was skinable. It took me only another few minutes to find a JARVIS skin that someone put together for SL.


So, the next thing to do was to strip my tablets all the way down, removing all of the software that I had placed on them over the years. I wanted these things to be as lean as possible, so there was no chance of failure. I also created another Google account for my house. A generic one that I could mess with however I wanted, and it wouldn't effect my other Android devices. (Plus, house guests couldn't accidentally stumble upon my email, Evernote, Dropbox and other personal goodies.)

Next, I spent some time adjusting the default behavior of the tablets. I wanted the lock screen to go away, the screen timeout to be longer than 2 minutes, and the brightness and sound to be cranked up to a reasonable value.

The one thing I couldn't find a solution to in off-the-shelf software was screen activation. Android tablets do not have a face proximity sensor, and when an Android device turns its screen off, it really goes to sleep in a traditional sense. Without a proximity sensor running, the only way to wake up a sleeping Android tablet (aside from hitting the power button) was to shake it, since the motion sensors are still running. Shaking a tablet that is firmly mounted to the wall, though, is a losing proposition.

Waking the things up eligantly was something I was going to have to do mechanically in hardware...

The Framing

The first thing to consider was how to place these things in the house so that they were at once out of the way and still immediately available. Also, being a bit of a persnickety gentleman, I was concerned about the aesthetics. I wanted these things to blend into the rest of my decor, and not look like the geek toys I want so desperately wanted them to become.

Keeping that all of this in mind, I immediately began to seek out wall mounted solutions. There are plenty of wall mounts for tablets on the web, but most of them are cheap "stick this to your wall" sorts of affairs, and none of them provided power. I was going to have to construct my own in a way that fit in with everything else. 

Even though I live in San Francisco now, I used to live in Boston and I carried that New England sensibility over to the left coast. That means I have a lot of muted colors, and my wall highlights tend to be white, wood frames. Fortunately, this makes for a relatively easy framing project, and a great way to hide cables to the tablets, give them ventilation and makes sure they are both securely hung on the walls and easily removable in case I need to get inside.

I walked down to my local frame store and picked up a couple of frames that were (a) larger than the tablets themselves, (b) made of wood, not plastic, metal or particle board (c) had  thick frames that I could cut into in order to make channels for the cables and plugs. 

Using a pullsaw, also called a Japanese saw (you see it there in the photo to the right), I very carefully cut the frames down to as close to as exact fit around the tablets as I could. I made the cuts on the 45degree corners, so that I could hide

the alterations easier.  To be honest, I went through a couple of frames ($25/pop) until I got the effect I was looking to achieve. Once done, I had to do it again with the second frame, then paint over the new seams. I kinda impressed myself. 

The next trick involved carefully carving out (or, in my case, haphazardly gouging out like an insane person) cutouts into the wood frames for the power plugs. Both the Asus and the Samsung use similar types of plugs that look nothing like USB jacks - in fact these are both quite large, about the size of a quarter, so the larger wooden frames worked great for hiding these huge plugs.

Whilest I haveth ye ole wood chisel in my hand, I continued my hacking away to place two screw mounts on either side of the frame. It was important to make these mounts as flush with the wood as possible, as it is important that the frame mounts tight and flush against the wall. It's a touch screen interface, and the rig can't bounce around on the wall when your poking at it.

The final cut to make into the frame had to be far more precise than my hack jobs. As I mentioned above, android tablets have a lot of sensors on board, but the one they do not have is a proximity sensor. On phones, the proximity sensor allows the phone's screen to either wake or go to sleep when the phone is placed close to, or taken away from, your face so your cheek doesn't accidentally hang up the phone or punch buttons. On a tablet, you rarely hold it to your face so the OEMs save themselves a sensor and just have the user touch the physical "on" button to wake the screen.

What this means for this project is that there is no software I can write, or applications I can download, that will allow me to wave my hand in front of the tablet to wake it up. I literally have to "punch the button" to get it to wake up. This is fine when the tablet is just sitting on the table, but punching the button is difficult to do when it's covered up by two inches of wood and screwed into the wall.

My solution to this problem was old-world mechanical: create a button mechanism that extends through the frame.

I don't own a drill press, so I used a vise and a steady hand to drill a 5/8th inch hole through the frame to where the tablet power button sits. I then cut a 2.5 inch length of 5/8th inch dowel stick, and shaped the end (with sandpaper) that would come in contact with the power button to conform to the shapes of the tablet edging. (Note: Aside from the Sony Tablet Z, there's no tablet I'm aware of that has a flat edge bevel. Both the Samsung and the Asus have tapered edges that need to be taken into account, otherwise the dowel will not seat properly against the button.) When I initially cut out the framing, I arranged the tablets so that their power buttons are on "top" of the frame, and the dowel stick just rests on top. I had to do a little extra sanding on the dowel stick itself to reduce friction when it was in the hole, otherwise I ran the danger of the dowel being held down against the power button causing the tablet to reboot.

Ta-da! A wooden "instant wake" button.

Keeping the tablets in place in their framing was easier than I anticipated. I cut poster board to fit the backing of the frame, drilling a hole in the back to allow the cable to come through. The poster board was then held in place by simple metal clips that you can purchase at any framing store.

That's it - both units are now ready for wall mounting.

The Wall Mounting

Ok, now for the tricky part. I have created two tablet mountings for two areas in my home: the master
bedroom, and the kitchen. The look I am going for is a free-float mounting, without any cables coming through from the framing. In order to obtain this effect, I ordered 6 foot long USB extension cables for both tablets and drilled holes in the wall behind each tablet, and again at the baseboard. This allowed me to thread the cable out the back of the tablet, down the wall and fish it out down below.

While this sounded simple, the mount locations of each tablet differed from each other in a couple of significant ways:

The mount in the kitchen was theoretically "easy," as the wall I was placing the unit on was an interior wall, without any exterior window framing. Therefore it was basically hollow, with simple 2x4 framing done every 18 inches. This would have been an easy effect to achieve, except the previous owners of the house crowded that wall with a security alarm control panel, and an intercom system for the front gate. Just slapping another piece of electronics on the wall would have looked junky if I didn't re-arrange the existing devices.

I'll spare you the gory details, but I took down the ADT security panel (revealing that lovely hackjob of a hole in the wall that the installation dude cut) and moved it down about 9 inches. Similarly, I pulled off the 40 year old security gate phone (70's wiring is amazing, uh....really) and moved it over about 5 inches. With the old equipment positioned as you see it in the photo, I was now ready to install the kitchen "JARVIS."

Fortunately, as I had hoped, the interior wall was completely hollow. "Wiring" in the unit, just
required me to attach the USB extension cable, electrical tape it together, and drill a 3/4" hole near the baseboard on the opposite side of the wall, which was next to an electrical outlet. If you are familiar with using a coat hanger to fish wires, the rest was very straightforward. (If you aren't familiar with using a coat hanger, uh, it's pretty much exactly what you are thinking: unbend it, make a hook in one end, and use it to fish the dangling cable through the hole.

Once all of that was done, placing the drywall screws in the wall where the tablet would be mounted was a snap. Just make sure you level the holes, measure twice, drill once. The tablet snapped right in without any trouble, and the dowel-stick mechanical button worked as advertised.

Voila! A neat, clean wall tablet installation.

Mounting the bedroom JARVIS would be a more difficult proposition, but I understood that going in. The wall location was not only an exterior wall, but it was between two windows - meaning that the framing would be intense. Exterior window placement means that the framing on either side of the windows consists of two 2x4's stacked against each other, and below each window would be a pair of stacked 2x4's to hold the window weight.

What this meant for the installation was, well, messy. I had to drill the 3/4th's inch holes for the USB cabling both at the tablet mount point, and down below by the baseboard, just like in the kitchen - unlike, the kitchen, however, I would have to locate the stacked 2x4's that were taking the
weight of the window frames and chisel a channel for the cable through them...which, of course, meant channeling through the drywall.  This went from a simple drill-and-hang operation to one that involved wall patching and painting. So be it...I had extra wall paint in the basement.

Once the channel was cut into the wall, threading the USB cable was just like the kitchen, except I used anchor staples to attach the USB cable to the 2x4's so it wouldn't be able to move or slide around - once that was done, I patched the wall up and hung the frame for the bedroom "JARVIS" as intended, making sure that everything was level.

Because of the amount of patching that was done, I waited 24 hours for the wall to dry. Once I was convinced it was dry, it was just a matter of applying the wall paint and hanging the tablet.

Volia (again)! Bedroom JARVIS.


Because this is a woodworking and home renovation project as much as it is a tablet installation project, this may not be for the faint of heart. However, I'm guessing there's a few shortcuts you can take that would allow you to get the project done professionally if you were willing to pay out some coin. (You can probably locate a framing shop that would do your tablet framing for you, for instance, and an electrician could mount the tablets a little easier.) 

However, if you have some extra tablets lying around and want to give it a shot, I highly recommend it. I've lived with the installations now for about a week, and I have to confess that I use them far more than I thought I ever would. Controlling Sonos from the wall alone is worth it, but once I added the software to control my Nest, the WeMo's, Epicurious, Cellar Tracker, Yahoo Weather, My Media Center and other applications by home automation nirvana was reached. I use both tablets differently in each location: Music control is a constant, of course, but in the bedroom I use the house Nest control, weather applications, security cam monitoring and video hangouts quite a bit. In the kitchen, I use the recipe and wine cellar applications as much as I use anything else. 

So, let me just leave you with a couple of videos to tempt you into trying this yourself. (Yes, I'm saying "OK JARVIS," instead of "OK Google." I'd like to claim credit for that hack, but that's a Google easter egg I'm exploiting.)


1 comment:

Anil Kumar said...

You have done a very impressive work! Great job, and great writeup. Thanks!