XOOM tablet based carputer project (work in progress)


UPDATE: here's the latest photo of the project...


i'm just starting a motorola XOOM tablet based carputer project. this falls somewhere in between the usual projects you see on here where the system is just used for mapping and the type of projects usually found on mp3car where the system is fully fiberglassed into the dash and acts as a fancier entertainment device.

i thought some of you might want to follow along, so here is my worklog on mp3car.com: http://www.mp3car.com/worklogs/155150-motorola-xoom-2003-jeep-grand-cherokee-4x4.html

i will not be posting many updates here on expo portal, so check the worklog for progress. however, feel free to ask me any questions on here if you don't belong to mp3car.

this was the old car pc project which this tablet system is replacing (it was based on a dockable HP laptop in the cargo area and this remote touchscreen):

the old system worklog: http://www.mp3car.com/worklogs/138507-2003-grand-cherokee-4x4-expedition-vehicle-worklog-dockable-hp-laptop.html
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copied from the worklog:

i wanted to document the goals for this project, so here they are in order of importance:

- every feature must function at least as reliably and intuitively as a dedicated factory or aftermarket device would.
- does not have to look "factory" but everything should be neat, clean, and not intrusive.

1 - Mapping & Navigation
must have: gps, offroad topo maps (offline capable), gps track & waypoint loading/saving, be removable to plan routes at camp, on-road maps (offline)
nice to have: on-road navigation (offline), traffic, POI search/info/directions (offline at least for gas, more when online)

2 - Vehicle Support
must have: display & search factory service manual in PDF, OBDII DTC code reading, DTC code database/lookup
nice to have: OBDII DTC clear, display misc vehicle attributes like voltage and external temperature

3 - Entertainment
must have: mp3 player, large mp3 file storage, factory steering wheel remote control button support, work with factory amp
nice to have: movie player, enough storage for many movies, A/V output compatible with a projector, act as WiFi hotstop for other people's tablets

some other ideas, if i get past the basics:

- multiple camera integration (i may just go with a separate screen for this, not sure yet)
- integration with external sensors like a temp sensor in the 12v fridge (and an over-temp alarm)
- ability to track vehicle if stolen
- ability to txt msg vehicle to shut it down if stolen
- ability to record photos/videos if stolen or during a break-in
- integration with APRS from HAM radio
- use of internal and external sensors to record trip info like pitch/roll, g-force, altitude, external temp, etc.
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the tablet install is coming along...

still some work to do on the electronics, but most of the "support chasis" is done. this all bolts in place of the factory radio - it provides an intelligent power supply, a USB hub, the OBDII interface, and will also have the BlueTooth audio adapter and a line-driver for the factory amp (the audio stuff isn't here yet). everything connects to the vehicle through a single radio harness plug.

also have most of the chasis and tablet mounting ironed out, here it is temporarily attached for a test fit:

i also still need to widen my CB & HAM mic hangers to fit next to the tablet now.


Nice work.

Have you decided on which navigational (for off-road) app you're going to use?

My Xoom is wifi-only. Ideally (my wish list) like to intergrate an external GPS antenna for improved reception/Xoom/APRS Ham on mine.


Nice work.

Have you decided on which navigational (for off-road) app you're going to use?

My Xoom is wifi-only. Ideally (my wish list) like to intergrate an external GPS antenna for improved reception/Xoom/APRS Ham on mine.

forgive the long post, i've done a lot of testing with mapping apps...

using BackCountry Navigator for now. i've also tried ViewRanger, Orux, and Trimble MyTopo. BCN had the best handling of large datasets, and a decent interface (but not great). it still crashes when trying to download a really large area at a high zoom level. i have a support ticket in and the developer is working with me on it. their first response was that it isn't meant to do that (download a whole state at zoom level 16 ;)). i explained that there is currently no good solution for overland users and that there is a market for it. one good thing is that it lets you use the microSD card for map storage (which some apps don't). i've read that the XOOM is will support a 64GB microSDXC.

Orux Maps is actually by far the most mature and feature-rich GPS app out there, but it will only let you download maps in 512MB chunks and has no paid-for map source option. it also gives you no visual way to see what you already have downloaded so there is no easy way to piece together a whole state.

i really wish Garmin, Delorme, or National Geographic would release a topo app for Android. they seem to be the only players with vector based topo maps. until then, we're stuck with raster maps which take a long time to download and take up a ton of space.

for around town maps, traffic, and navigation, i'm using Google Maps since i have a 4G device.

when on longer trips where internet service may cut out, i'm using CoPilot Live for my road map and nav software. CoPilot does use vector maps and can download the entire US easily. it can show you alternate routes when doing navigation, speaks directions, has day and night themed maps, and actually does show many small forest roads. i've been using CoPilot with my phone for a while and it's only given me a completely wrong route once so far (as always, GPS is just an assistant, you still need some sense of where you are going). i also tried Sygic GPS Navigation and thought it was terrible. i have not tried the TomTom app, it's very expensive and only has mediocre reviews.

i've used the tablet twice now off-highway and have not had any problems with GPS reception (with the internal GPS unit). does the WiFi version not include a GPS module at all? i've heard good things about the Dual XGPS150 unit.


electronics first-pass is complete and it all works! i went for 2 short test rides to make sure things behaved as expected... there are still a few immediate to-do's but it's 90% there.

High Priority ToDo:

- track down some noises in the audio
- verify all mounting is secure enough for offroad use, then paint all the bare aluminum
- get steering wheel remote buttons working
- purchase an OBDII app and test

Ongoing ToDo:

- refine Tasker actions to automate even more of the behavior and work out any bugs
- tweak all the app's settings to get things just right for daily use
- improve setup for night use
- future enhancements like external sensors, remote management, multiple cameras, etc.


Wow. Nice integration.

I too am interested in your android gps apps and offline functionality. I heard national geo released The Ultimate Outdoor MapKit which looks promising. Not sure how many maps you can download or how well the android gps app works but might be worth taking a look at.


Wow. Nice integration.

I too am interested in your android gps apps and offline functionality. I heard national geo released The Ultimate Outdoor MapKit which looks promising. Not sure how many maps you can download or how well the android gps app works but might be worth taking a look at.
thanks! and thanks for the heads up, i had not heard of that one...

it says here it has a "mobile app for iOS and Android" (link...), but i can't find it in the Google play store still, nor the Apple app-store. i'll have to watch for it, and for more reviews (the Amazon 2 are bad so far, but are not mobile-specific).


i had to completely re-do the chasis. i was getting significant noise due to EMI from the tablets 4G data connection. all the supporting electronics are now inside the old factory radio shell, with additional shielding as well.



still a few details with the hardware, but i've been working on the software side for a little change of scenery (automation, UI customization, and evaluating apps).

the home screen is setup to display some info and give access to all the commonly needed functions:

i'm setting up Tasker so that the tablet is always in a "mode". the modes control things like screen brightness/timeout/lock, GPS/WiFi/4G/BlueTooth status, launch/kill apps, music stop/start, etc.
- "Default" is for normal around home or public use
- "Jeep" is for when docked and has sub-modes for awake, sleep, and hard-sleep
- "Trailside" is for the scenario of reviewing maps outside of the Jeep with other folks on a trip

whenever the tablet looses power (Jeep turns off or i remove it from the dock), i'm prompted for 10 seconds to change modes, otherwise it remains in "Jeep" mode but enters the "sleep" sub-mode. there will be more sub-modes for "Jeep" later (day/night, remote-manage, etc).

the lock screen is also setup to give me access to the modes. swiping to any mode icon unlocks and switches to that mode. the main unlock icon just unlocks and remains in the current mode. the lock screen isn't shown when the Jeep starts up, this is mainly for when in other portable modes.

- the backgrounds are photos i took of the Jeep and cleaned up in Photoshop.
- the icons all came from the app "MetroStation icon pack"
- i'm currently using the free version of Apex Launcher. CyanogenMod 10 has a new launcher (Trebuchet) and it's still got a few bugs. once 10.1 is stable for the XOOM, it sounds like it'll have all of the Launcher features that i want built-in.
- the weather widgets are from the app "HD Widgets"
- the music control widget is from the app "PlayerPro Music Player" (ICS theme for the widget and using Holo ICS theme in the app itself)


very cool. interested to see a wiring schematic if possible and part list!
thanks! i'll put together a full parts list once it's finished and if i have time a rough schematic.

currently i have ordered a different line-driver to see if it fixes a couple of audio issues, and still working on dialing in software stuff as i have time. i also need to beef up the main mount between the custom cradle and the chasis as it has too much flex, and need to widen my CB and HAM mic attachment points so they fit next to the tablet.

i also left the tablet in the Jeep overnight for the first time in the car-sleep mode and it was off the next day. i don't know if it couldn't handle the 29* weather (what would be a sucky limitation), or more likely if one of my Tasker actions is not configured correctly and is running the battery down too fast or crashing. i'm running a test in that same mode but inside the house to see.