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  #21  
Old 02-05-2015
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theksmith theksmith is offline
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Default Re: Android Tablet as a Head Unit & GPS - New Install
the support electronics

i mentioned before that i'd explain the electronics behind the mounting plate, so here's a photo:



...much simpler than the previous install. partially because some things are spread out in other locations, but also the whole system is indeed less complex.

- the RCA plugs on the factory radio harness are from the previous install, they aren't used anymore.
- besides power related items (the tablet charger and a dual 12v outlet with dual USB charger), there's the MHL (HDMI) adapter, and a delayed-off relay which controls the power to the tablet and accessories/stereo components.

here is the "master diagram" for the whole system:



the diagram was created on the new tablet with the free version of a really neat app called DrawExpress (http://www.drawexpress.com). after a couple seconds with the instructions it becomes a very easy to use and is a quick way to create diagrams, flowcharts, mind-maps, etc. i added the little photos using Photoshop after exporting the main diagram.


more about power & the timer relay

the delayed-off relay is used because the WJ (like many vehicles) cuts out accessory power while cranking. this means when you turn the key to on - then crank - then back to on, the bluetooth devices (audio adapter and OBDII adapters in my case) loose power and then have to re-pair. this takes a couple seconds each time and the rapid changing of states can also confuse the tablet.

i had previously adjusted my startup/sleep scripts on the tablet to wait a few seconds when it saw a power state change, then double check the condition before acting. this worked temporarily, but the loss of power to the BT accessories still meant a re-pairing had to happen and therefore a longer startup-up cycle before everything was stable after cranking.

on my old tablet i also had to use a specialized power supply that could "survive cranking" - i.e. keep a regulated voltage output while the input voltage fluctuated. people think of cars as 12v, but during cranking the voltage often can dip to ~7v and while running the alternator might put out as much as 14v. fortunately this new tablet and all the other pieces to the system run on 5v, so their standard little power adapters can still provide a clean 5v even during the 7v dip.

so i went with the Hella 996152131 adjustable delayed-OFF timer relay (http://amzn.to/1zTsOPs) to accomplish this delayed turn-off.

there are some other modules on Amazon and eBay (like this one: http://amzn.to/1LP9UfI), but there seemed to be a lot of confusion on how to configure them and what you could expect. it turned out that the Hella relay's own circuit diagram was also a little lacking in clarity, specifically with the importance of polarity when hooking it up - so i created a better diagram for others to reference:



Hella also offers a delayed-ON version of the relay, part #996152151:

FYI: a "new version" of the electronic delayed on/off module i had avoided came out recently - it appears to be much simpler to use and gets good reviews. it may be a more flexible approach than the Hella relay: http://amzn.to/1zTtF2F
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  #22  
Old 02-05-2015
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scottL scottL is offline
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Lightbulb Re: Android Tablet as a Head Unit & GPS - New Install
Thanks for that detailed explanation Kbro, i totally get it now. Just need to purchase a couple dongles and i'll be more up to speed
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  #23  
Old 02-05-2015
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theksmith theksmith is offline
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Default Re: Android Tablet as a Head Unit & GPS - New Install
Originally Posted by scottL View Post
Thanks for that detailed explanation Kbro, i totally get it now. Just need to purchase a couple dongles and i'll be more up to speed
you're a dongle!
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  #24  
Old 02-09-2015
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theksmith theksmith is offline
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Default Re: Android Tablet as a Head Unit & GPS - New Install
i guess i can call the mount "finished" now, paint is dry on the microphone clip bracket and everything is re-installed.

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  #25  
Old 10-28-2015
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theksmith theksmith is offline
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Default Re: Android Tablet as a Head Unit & GPS - New Install
while messing around with deleting the wood trim on the doors (http://offroadpassport.com/forum/showthread.php?t=4394), i realized how broken my factory moisture barriers were. i decided to make some new ones out of a closed cell foam noise dampening product, killing 2 birds with one stone. like many ideas, this has turned into a whole project in itself...

here are the old door panel liners from the back doors. they are made out of black plastic with some sort of tar paper like coating which was cracking all over.



i had to clean off the butyl rubber "glue" that was holding them on, and a bunch of dust/mud.





i went with Stinger RoadKill dampening matt. it comes adhesive backed and is a 1/4" thick closed cell foam (won't absorb water). 12 square feet goes for under $50: http://amzn.to/1kNTX0k

i know that MLV would be the best thing to help block the low frequency noise from exhaust and MT tires, but i couldn't justify the cost of that stuff on an old Jeep. i also liked the convenience of the sticky-backed Stinger pad, it's easily re-positionable so it can be peeled back if a window regulator or whatever needs to be fixed later.

using the old moisture barriers as templates, i was able to easily cut out the new material for application as 1-piece pads so that they would block dust and water from the inside as well. here is the test fit on the door panels to make sure all the cutouts for fasteners were correct:



installed:



i also added some DEI Slim (shallow) Boom Mats to protect the speakers from the elements: http://amzn.to/1MV6MfK

acoustically, my understanding is that these act *sort of* like putting your speaker in a small sealed box. i say "sort-of" because they aren't rigid by any means, so whatever effect they have is minimal.

they certainly aren't going to make a speaker have more bass - a common misconception. if anything they might have tightened up the rear 6.5" and improved their power handling, which would be a good thing in my case since they are the lowest rated (wattage capability) of any part of my system.

i didn't notice any difference in the sound, but when it comes time to do the front 6x9's i'll have to see how those are affected since they're really where most of my volume comes from.







almost forgot to takes pics, but i did do a little Dynamat style (butyl backed foil) sound deadening. i didn't really have major detectable vibes coming from the metal door panels as the WJ was a luxury vehicle in it's time and so everything is pretty thick and solid.

i just used some small pieces around a few connectors that might rattle against the metal and then a few strategic squares. GT Mat Pro (50mil) was the actual product used: http://amzn.to/1GL4F17







i'm not sure if i can tell any difference yet all of this only done to the 2 rear doors so far, but the process went quick so i plan to do the front doors next, and then the firewall (since i need to remove the dash soon for other reasons). i'm sure it will be noticeable once more of the Jeep is dampened and i can certainly used the increased insulation properties to keep that precious A/C inside during Phoenix summers too!



a while back i had also gone through and tried to fix any major rattles...

one big culprit were the lashing points on my custom rear shelf thingy. especially since the subwoofer box is currently ratchet-strapped down to the top of it (not shown in this pic):



these style d-rings were the major rattlers (when not being used):



so i replaced them all with these Canyon Dancer Tie Down Rings meant for motorcycles/ATVs/etc.: http://amzn.to/1LWy5qa







i've also been playing around with EQ-ing the system again using some very basic RTA (real-time-analysis). i look forward to more noise suppression so i can better enjoy the tuned sound of the new system at freeway speeds!
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  #26  
Old 01-14-2016
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theksmith theksmith is offline
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Default Re: Android Tablet as a Head Unit & GPS - New Install
this whole system has worked pretty darn well for just over a year now with only minor updates...


dock power connector repair

one of the little POGO connectors (spring pings) in the power connector of tablet dock stopped being springy.



even before this i'd been having some trouble with the tablet bouncing up occasionally on really rough roads just enough to temporarily lose power. so i decided to hack up a power adapter meant for a regular Micro-USB cable which has a strong magnet and smaller (more precise) POGO pins.

the photo below is the first one i cracked open, but it wasn't put together in a very solder-friendly manner so the one i actually ended up using was this: http://amzn.to/1N9Bdyl



while de-soldering the old pins to get them out of the dock cleanly, i accidentally touched the opposite side of one which made for a nice little welt and some cussing.



the next step was to Dremel out a slot from the bottom of the dock to place the new connector in. it turns out i had to cut out wider than the holes form the old pins anyway, so i could have just ripped those out and avoided the de-soldering incident, argh!



i soldered new wires onto the pins of the connector that i hacked apart, and attached them to a regular USB end so that i could use a regular cell phone charger.

then the bottom edge of the tablet got covered with Saran Wrap to protect it from glue and was placed it in the dock to align the new connector. i used super-glue to attach the hacked up connector in the slot i had made. i also filled in the empty pocket you see here with RTV once the super-glue dried.



i re-attached the bottom of the little dock piece to cover up the RTV and make a clean exit for the wire out the back just as it had been before surgery. this new connector with the magnet seems to so far have stopped the issue with the tablet bouncing and loosing power occasionally.


tablet screen protector

i got tired of the matte screen protectors always showing so many smudges and oil from fingers, so i bought a new tempered glass protector (http://amzn.to/1N9A1uR). still gets smudged, but wipes of easier than the matte ones and doesn't scratch as easily.


upgraded Android

over the holidays i upgraded to Android Lollipop, the latest official version for the Verizon edition of this tablet that i have. i spent the next couple weeks dealing with the affects of that:

- the app i developed to integrate the steering wheel stereo controls wasn't working reliably. i think i have a fix in place and will update the github repo this week.

- quite a few things in my custom Tasker setup had to be tweaked, mainly using more of the Secure Settings plugin instead of built-in Tasker actions. also the timing of everything needed subtle changes.

- the Media Utilities plugin for Tasker no longer worked, but it seems like just letting my main music apps (Pandora and PowerAmp) use their built in abilities to pause/restart on bluetooth connect/disconnect is working.

- the beta version of the xPosed framework for Lollipop seems fine, but the Gravitybox app is missing a few things. the AppSettings app is working just fine.

- the only real advantage i've found with this new version is that bluetooth and cellular data connects much faster when i turn the Jeep on and the tablet comes out of sleep... particularly the AptX connection to the BT audio receiver, so music starts back up a second or so faster now.
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  #27  
Old 05-02-2016
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theksmith theksmith is offline
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Default Re: Android Tablet as a Head Unit & GPS - New Install
i've had a couple other Jeep/Dodge owners use the open source Android app i built to control a tablet or phone from the factory steering wheel buttons - but a guy just emailed me having now used it in a totally different vehicle platform. excited to see it be useful for others! video from him below:

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  #28  
Old 11-13-2017
redman333 redman333 is offline
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Default Re: Android Tablet as a Head Unit & GPS - New Install
I saw your steering wheel controls app that allow the physical buttons on the vehicle to be used as buttons on an android unit. Can this go the opposite way also. Could a button press on the android unit control a function on the car. I have a Lexus with the AC controls built into the same circuit as the nav screen so I am mounting a tablet on top of the nav screen. However this covers the AC controls. Would your software be able to control the AC functions at all? I know I can make custom home screens and such and have buttons there that do different things so I'd have to figure that out but my main issue is trying to control the vehicle by tablet.
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