Hello!

Thought I should post up a log about what I am up to.

The plan:

Plan as it currently stands is to run a Google Nexus 7 tablet as my carputer.

The story so far:

R and D phase.

I have found a very nifty app called tasker that allows you to do some basic but powerful scripting, it's all done through a GUI, and you can have something like "If battery is Charging or 100% then set screen to be on with no timeout period".

That means by simply wiring in a charger I can have the tablet auto turn on when the car starts, and because it's just like pressing the power button on your phone it's instant.

Next up was the audio, I can have it sync to the wireless at home no worries at all and it will take expandable storage. AM/FM radio is another problem, there isn't currently an easy way to directly receive AM/FM because there simply isn't drivers for USB tuners, if you can go through a problem you have to go around it. Tunein is an awesome app I found that lets you stream so many radio stations it's ridiculous, it even has my local country radio that has a range of about 10KM.

This means I need internet at all times, clearly the only choice is Telstra NextG. I have two options, I could try hack together a 4G hotspot to be always on or I could use my old HTC Desire and use tasker to turn WiFi on on charge. So I started taking the HTC Desire apart last night to find an external antenna connector, all my searches said it did not and I was wasting my time, 40 seconds later I had found 4 antenna ports on the board, two for GPS and two unidentified ports. Testing was really easy, I took a small pin and put it in the bottom port 3G reception went from nothing to full, the top port made WiFi reception increase. Now I just need to find a good car antenna with a TS9 connector, or pig tails to suit.

So far everything has been pretty easy, I mocked up a real size paper tablet to check fitment and it looks like everything will line up pretty perfectly. I had the phone lying around and a Nexus 7 is only about $300, antenna maybe $100, and an Amp. Charging the Nexus and using it as a USB host is a simple Kernel patch.

The Amp. This is where I am stuck, I really just need an Amp that will drive the stock speakers in my KJ GTVi, i'm not really after anything fancy and I am not planning on replacing any speakers/splits/wiring. It would need to take either a 2 or 4 channel output, I'm not to picky but I don't want to spend a bunch.

Cheers!

I have an older model amp mate not sure what power output but it may suit what your after !

Mate any more research or development? I like the sound of this. There is a chinese double din unit with a removable 7inch face (basically an Android tablet) have you seen that? Their app or OS must be available on the net somewhere.

Procurement:

Well things took a downward turn with the mobile as a hotspot, I can't find a connector for this port. As far as I can tell it's almost identical to a u.fl but it's missing a center pin. If anyone can tell me what port it is that would be awesome!
http://i.imgur.com/vKDTZ.jpg

Anyway, also got the tablet today and WOW it fits like a glove.

http://i.imgur.com/5N5rm.jpg
http://i.imgur.com/ZIOWg.jpg

I also bought a small stick on glass antenna, no great but it should do the trick. It's kinda useless without a phone connector, I might have to go try a hotspot and see if I can make it turn on with the car.

http://i.imgur.com/cEw30.jpg

Tablet clears the metal no worries at all, might knock up some retaining brackets at work tomorrow

Well after yesterdays failures with the phone I thought, I can do this or I can do this right. 4G hostspot with 4GB a month, a good amp and some cables.

http://i.imgur.com/rcVOs.jpg

http://i.imgur.com/A4eS9.jpg
This is looking up in the boot, the holes are for mounting the amp upside down. I really didn't want such a big amp but it's easier and cheaper to get a big one locally than a small OEM ones from overseas.

http://i.imgur.com/sqY6R.jpg
http://i.imgur.com/PDBTM.jpg
Amp mounted, cabling done

http://i.imgur.com/ZVAhZ.jpg

Cabling inside, everything is removable and crimped well. To return it to stock all you do is unplug the main white connector and plug back in the stock radio.

That looks awesome! :-) The possibilities are endless for apps etc. Regarding power will you just let it charge up and discharge when the car is off or charge all the time? Also you can add endless Bluetooth devices.

So is it actually all installed? How did you end up mounting the tablet to the fascia? Any more pics? And top work, BTW.

Good work. Very well done.

But how do you get audio signal from the Nexus 7 to the Amp?

I'm a bit slow with these things. You have data replacing your antenna (which will give you google maps, google nav, etc).
I'd like to know more about how you have wired in a charger. I take it the 5v from the cigarette lighter would be enough voltage. But how did you wire in a mini-usb plug to get pwr to the Nexus?

Which plug on the Nexus do you use for audio out to the speakers/amp?
Is it just from the Nexus' headphone plug or does it also run off the mini-usb? And then it runs to the amp, or the loom adapter?

More to come soon, car is off at the mechanics and I can't seem to sort the bloody power out!

Audio comes from the nexus, down a set of RCA's, split from 2 to 4, into the amp. From the amp speaker wire runs back up to the center console where I have modified a converter plug (the kind that take your stock connection and plug into an after market HU) plugged in. I did it this way because I wanted to retain all the stock speakers and wiring.

The tablet is actually held in with pegs, I was looking for a bit of wood to hold it in there and pegs off the line were the perfect size and fit. I just super glued them onto the tablet. Not elegant but works so well and was free so I really can't argue.

POWER:

The only practical charge point is from USB. The problem with standard USB is it's to slow, the tablet will only accept about 450mA from USB and wont change it's state to charging so the screen stays off. The stock charger has a resistor between the data pins to signal to the device that it can draw full power, around 2000mA, the problem is that no car charger seems to do this. I have wired up an inverter and it works perfectly, except for the really dirty power it sends out, it's so bad that the tablet refuses to enable the audio processor(or it fails or whatever, no audio output from the tablet and just heaps of inverter whine). So I am stuck at the moment, I need to either modify a USB cable or wait for my USB break out cable to arrive and see if I can charge better with that.

In time I would like to some how have it trickle charge when the car is turned off, maybe via a small second battery or something. That should be pretty easy.

Ah ok. I was considering my own 7" tablet dash PC. And was thinking along the lines of having a simple/small head unit mounted in the din slot... but pushed back maybe. With the tablet mounted in front. With the tablet getting power from the USB of the head unit, and the tablet feeding audio back to the headunit from the USB also (same as my phone currently does... gets pwr and gives audio over the headunits single USB out) (or possibly audio back to the headunit over the 3.5mm audio out plug...).

I was thinking that would obviate the need for an AMP to pwr the speakers (done by the headunit), and provide power to the tablet (again by the headunit).

I don't know if that would provide enough power to the tablet to fix the problem you're having with gutless charging rates.

I currently have a double DIN headunit... and I dont think it would fit recessed back into the DIN bays. But that shouldn't be a insurmountable problem.

And you sir, you get 100% kudos for showing that a Google Nexus 7 fits like a glove in a Magna dash.