Power Supply

USB chargerTo power the tablet the plan was always to take a USB car charger and wire it directly into the car 12v power. This adapter would be hidden in the dash behind the tablet. I went and found a good power supply that put out a full 2 amps on each USB port. This was very important to maximize charging of the tablet. I needed a dual USB charger because one will be used for the tablet and the second would be simply to power the LED in the Power switch. HERE is the USB charger I got. In the following video I talk about the plan for this part of the build.

As I took this thing apart I realized there was an LED light already on-board. I assumed it was being powered by 5v so I decided to snip it off at the legs and solder some wire to them and extend that wire to the LED on the Power switch.

In the following pictures you can see how I reassembled the USB charger case over the cut and soldered power supply. There are two wires coming out of the end that are for the 12v supply from the car and two other wires sticking out of the side that was for the Power LED.

psmod1

Once I put it all back together, minus the cut off pieces, and looked at it I started to feel like it didn’t really fit the aesthetics of the rest of the project. Even though it was going to be hidden in the dash behind the tablet I would always know it was just a plain old Amazon car charger hard wired to the car mains. After looking around my room and in junk drawers and boxes of old electronics parts I found an old USB charger for MP3 player or something. It was the perfect size and was a nice black square that would suit this project much better. I took it apart and went about doing a little cutting and trimming to get the circuit board of my charger to fit into it. Because of where I already added the fuse holder in the main power supply wire I had to have it sticking out of the end of the power supply case and then looping back into the side of it. I also used a Molex connector for the 12v/5v connections and had that sticking out one side also. I like it better this way. It gives me quick and easy access to the fuse for replacement and a little asymmetry is always cool, just look at the USS Enterprise. I know it’s not asymmetrical in the classic sense like the Millennium Falcon but I’m a Trekkie so what do you want!

The above pictures show the power supply in place in the dash. The two blue connectors you see are the 5v pos/neg coming OUT of the charger from the on-board LED that will go to the LED in the Power switch.


 

On the passenger side there is a 12v power outlet that is controlled by the key. This means that when the key is on or in the Accessory position the outlet is powered. My plan was to go in behind this outlet and splice into the wires for it. After doing this I was getting no power at all! I didn’t panic. I checked all my steps and still, no power. I checked everything again and the only solution that I could come to was that the outlet never worked in the first place! I had never used it before and once I reconnected just it to the power lines it still does not work. Time for Plan B; taking the power from the radio wiring harness. This was a very stressful and harrowing experience! There is no record of this process. There was very little slack in the wires which meant there was no room for error. If I screwed up a splice or cut the wire clean through there would have been no way to fix it and I would have been hours working loose the wire and unwrapping it from the bundle for repair. After finally getting jacked into a constant 12v power supply from the car (yes, I went constant power instead of accessory) guess what!? The 5v I thought I was getting from the USB charger LED did not work and the battery was not charging either! So, out comes the power supply, thank god I just have to unplug the Molex connector at this point.

So, here is the new set up… resistor in place on second USB cable to power the LED on the Power switch on the tablet. And also, SUCCESS! blue LED ring for the first time. Lastly, the power supply in the car with the USB cable for the LED and for the tablet.

 

Custom tablet enclosure part 2

If you remember, the “back” of the tablet enclosure I bought became the piece I used for the front of my enclosure. It had a groove in it in the shape of a square. Most of it was cut out when making the hole for the tablet screen to sit in. There was a part of the groove that was visible on the part of the enclosure that was under the tablet screen. I filled that groove with the epoxy putty that is such a PIA to sand sand and paint. Here are several pictures of the enclosure front going through various stages of completion.

In this video of a power test you can see that I had already applied primer and paint. I have since gotten rid of most of of the putty bumps.


firstplaceThis is a shot of the custom tablet enclosure in place. After looking at this and thinking about how I wanted to attach the tablet enclosure to the dash/bezel I came to the conclusion that I would need some screws in place to do it. By this point I knew for sure that I wasn’t going to use a bunch of epoxy putty to fasten it to the bezel because, you know, sanding.

I decided to build some “ears” onto the top of the factory bezel. These ears would have threaded holes that I could put screws into from the back of the tablet enclosure to hold it in place and from now on would be called mounting brackets. The way I made the mounting brackets was to drill a hole into the top of the bezel, one in each spot a mounting bracket was going to be, gand screw up from the bottom a wood screw into each hole. I then got some hammer-in nuts and with the epoxy putty I love using, but not sanding, secured them in place. Confused? Well it’s almost 2 am. Just look at the pictures;


After getting the tablet fit into the front part of the shell that I made and making sure all the buttons worked it was time to flip it over and take a look at the back.

I could not find a “low profile” micro USB cable. I guess when things are already called micro they don’t make smaller versions of them. The only way to make this thing fit was going to be to trim it down my self.

After trimming the hell out of the USB cable and epoxying it into place (I love my compound epoxy btw) I needed to test to make sure it was still working.

Built in radio antennas…

This is just a short bit about what I did to make sure the GPS, LTE and other antennas remain connected to the tablet since I was not keeping the back of the tablet attached.

I had some lofty ideas but in the end the simplest one was chosen. It also was the one that did not involve any more soldering!

I decided to just cut out the pieces of the back cover that had an antenna embedded in them and glue those pieces onto the contacts on the tablet. These contacts are very small and would have been nearly impossible to solder or connect wire to using any other method.

 

Connecting external switches…

As I am writing this I again realize that I did not take pictures of the “before” part of this segment… (insert Picard face palm here). Just take my word the the little thing in this picture was connected to the edge of the tablet with a ribbon cable. PWR - VolUp - VolDnThe three little silver bumps are actually tiny switches that the Power/VolUp/VolDwn buttons on the tablet case activate when pressed. The plan is to wire these little switches to bigger ones on the front of the tablet enclosure so they can be operated in an easier to access way like the other controls in your car. This proved to be a very tedious and nerve wracking experience.

Contact pads

Those silver bubbles are actually just that. When pressed down by the plastic button in the tablet case they close a circuit and signal the tablet to do something. Those bubbles are covered and held into place by some Mylar tape. After pulling off the Mylar and the bubbles you see what is really going on underneath.

Power or Volume Down?Here is my first set of wires soldered to the pads. You can see that I had to solder one wire to the little center pad and then one wire had to be soldered to the littler ring going around the center pad! This went pretty well and I was very pleased with myself. I thought this would be a breeze. Ha! How wrong was I!? The next two buttons tried my patience and my faith. When finished, the soldering job looked like that blob of drywall mud covering that hole you put in the hallway wall while practicing street hockey slap-shots as a kid.

Revel in my glory with me, wont you?

All 3 sets of wires soldered and epoxy'ed in place.
All 3 sets of wires soldered and epoxy’ed in place.

3for3angle

Switch assortment

This is the assortment of switches I purchased. None of the rocker switches I got would work because they all had a common ground. Because of the way the tablet (this and others from my research on the web) has the buttons set up you cannot share the ground. This is why I am using momentary switches for all. It’s not a bad solution. I could have spent more time looking for a usable rocker but I was impatient.

switchesinThis is the switch I used for Volume control, Momentary Push Button
This is the switch I used for the Power button, Momentary Metal Push Button

Custom tablet enclosure part 1

I knew I wanted to remove the tablet screen and electronics and mount them into my own shell which would be built into the dash. I’m realizing now I did not video that part of this or take pictures! There are tons of pictures out there about opening these types of tablets. Here is one of them that I watched, LINK TO VIDEO, it is an actual tear down of a tablet similar to the one I am using.

This is the plastic enclosure I ordered to use for this project, BUD Industries TGB-32612-B. My plan was to cut out an opening in one side of it that the tablet screen would drop into. Here are some pictures of my first attempt. I ordered two of the above enclosures just in case. I actually ordered doubles of all my parts except for the tablet itself.

After some very loud and prolonged Dremel action I felt like I was making some good progress.

After getting started with the back side of my enclosure I was able to again complete some very loud and long Dremeling and again using just eyeball measurements end up with a pretty accurate cut-out for my tablet screen.

 

Here is a video of the screen in place after some additional grinding and sanding to get a nice tight fit.

Here is my beginning work on the tablet enclosure to get it to fit into the factory radio bezel,

This is a video talking about the back of the custom tablet enclosure also…

These pictures show a minor problem regarding how the tablet enclosure aligns when attached to the factory radio bezel. It also shows examples of a constant problem with this build, how to finish the surface of the epoxy putty. I’ve said it before, sanding and more sanding was the key.

 

 

In the beginning…

My idea was to keep the factory head unit, because it has touch screen controls for the radio, phone, SAT radio and climate controls, and add a tablet for NAV and “futuristic coolness”. Below is the removal of the bezel. I learned how from this VIDEO.

After removing the bezel and the radio I can see what I have to work with inside the dash.

Here are pictures of what I did to allow the radio to be mounted in the dropped or low position that I want.

Here is the radio set in to its new position,

Here are a couple of pictures of the radio after I took the plastic parts off the edges. I made two holes in the radio housing plastic on each side of the radio. This let me put a screw thru the radio and into the holes to mount the radio in the housing in the new position.

Now that the in-dash radio bracket has been modified to allow the radio to move to its new dropped position the bezel needs some work too,

Now that I have made room inside the dash for the radio to be lower I need to work on the bezel to get the radio in its new position to fit.

After I got the epoxy putty put in all around it was a huge pain in the butt to get that stuff sanded and painted and looking like a finished surface. In the beginning every time I sanded and painted the putty and bezel you could see the edge of the putty where it met the plastic and every hill and bump in the putty surface came into sharp relief. I considered all kinds of crazy options like coating the whole bezel with Plasti-Dip or covering it with hard drying spray insulation so I could sand the whole thing down and have a uniform surface to “lacquer” and paint.

It was a huge hassle and really had me stalled on this project for a long time. In the end I realized that I was using too fine a grit sandpaper and that really, sanding was the only way I was going to fix this. Here is a video and a bunch of pictures of this entire process.