How to: Android Nexus 7 HU install
 

Hi guys,

First meaningful post - got my first Impreza last week, a Hawkeye Wagon. Love it!

Anyway, my previous motor forced my hand into changing the double DIN stock unit for something a bit more suitable, I had a Google Nexus 7 lying around and got to investigating how this might be used. Long story short, took about an hour to get up and running in the Impreza as the kit list was a bit shorter, but I'll include all the possibilities here in case you're curious.


Why?

At the time of my first install it was a lot more cost effective than using one of the more flagship Android devices that Clarion, Pioneer etc offered. Looking now though it could be debated...
..However, using a pure Android device will allow you full customisation as to what you may need; reversing camera, always up to date Google Maps GPS and basically anything else Android can do!


How?

The Nexus 7 screen is just marginally smaller than the standardised double DIN dimension, and so fits perfectly in the space.
Using a single DIN headunit behind the Nexus, the speakers are amplified, the Nexus supplies its sound via 3.5mm jack to the aux in, and bluetooth hands-free calls will override the Nexus connection and therefore work perfectly. A headunit with external microphone input is necessary, as the builtin mic will be blocked by the Nexus.


Parts list:

Required:
- Nexus 7 (had for £50-60 on Ebay atm)

- Single DIN bluetooth headunit with external mic and aux in (got my Pioneer for £25, Ebay)

- Carputer Android ROM, in this case I use a ROM called Timur's Kernel. £15

- 2.5mm microphone for Bluetooth voice calls
http://www.ebay.co.uk/itm/2-5mm-Blue...item25aa68e6b2

- USB OTG host cable
http://www.ebay.co.uk/itm/Micro-USB-...item419a7aca02

- Micro USB right angle cable
http://www.ebay.co.uk/itm/Micro-USB-...item35e05878db

- 3.5mm to 3.5mm audio cable

- Additional cigarette lighter socket to power the device(s)
http://www.ebay.co.uk/itm/12V-Waterp...item233d246731

- 5.1A cigarette USB charger
http://www.ebay.co.uk/itm/New-EasyAc...item3ce2c33c44

Optional:
- USB hub
http://www.ebay.co.uk/itm/7-Port-Mai...item19fafcda92

- Video grabber for reversing camera
http://www.ebay.co.uk/itm/WGF-EasyCA...item2ca026007c

- Any reversing camera with composite video

- USB DAB radio receiver with RTL2832U chipset

- DAB antenna or antenna adapter to fit USB receiver

- Fuse tap (very handy for extra power sources)
http://www.ebay.co.uk/itm/2-Add-A-Ci...item27bf1644ed


So that's the parts list out of the way, I'll show you a quick pic of the end goal:


https://cimg0.ibsrv.net/gimg/www.sco...a050d2baa0.png


So in my instance, I have the image above but plenty of USB devices can be added to make for a feature-rich installation.


Install:

- Remove the gear knob
- Pull on the gear knob plastic trim, pull towards the back of the car for it to unclip from the console. Put to one side.
- Disconnect the cigarette lighter
- Unscrew the two screws (bottom left corner, bottom right corner) of the climate/stereo bezel
- Working upwards from each corner, gently pull on the bezel - there are two clips in the top left and top right corners. It's a bit stiff but it will come apart.
- Unscrew the climate controls from the inside of the bezel, a screw in each corner
- Unscrew/remove existing headunit
- Feed the cigarette socket towards the bulkhead, up and over the plastic trim and pull through the headunit area - this is to gain comfortable access to the positive/negative wires
- Tap into the wires however you see fit, (I believe the colours are red/yellow and black/grey) - connect the wires to the secondary cigarette lighter socket (previously I needed to use the fuse tap to separately wire the cigarette lighter as the original cigarette lighter was too far away)
- Feed the original cigarette lighter back to its normal location
- Connect the USB charger
- If using the USB hub, you will need to cut the mains lead cable, cut the USB A-B cable, and join them together (creating a USB > power jack cable)
- Connect the (USB hub) and USB OTG cables to the USB charger
- (Connect USB hub to OTG cable)

- Here's the interesting part, how to attach the Nexus to the climate/stereo surround. I want easy access to the Nexus without making any permanent modifications (either the car, or the Nexus in terms of modification), in my case I used velcro but also used adhesive to apply the velcro to the two surfaces;
- cut 4 thin strips and stick to the inside of the bezel
- cut 4 opposite strips and attach the velcro together
- carefully line up the Nexus, and stick to the velcro

Resulting in:
https://cimg1.ibsrv.net/gimg/www.sco...8f86903433.jpg

https://cimg2.ibsrv.net/gimg/www.sco...72411cc9c2.jpg


https://cimg5.ibsrv.net/gimg/www.sco...aa7f9d0c38.jpg

Nearly there..

- Using the Subaru mounting plates for the headunit, place the single DIN headunit in the top half (sorry didn't get photos for this!) but also as far back as possible but not enough to foul the structure of the dash - from memory, I believe the headunit was set back by about half an inch from the front edge of the mounting plates.

https://cimg8.ibsrv.net/gimg/www.sco...45ffd64ba1.jpg


- Connect the Nexus to the power, and hook up the 3.5mm audio cable together

- Re-attach the bezel, gear knob surround etc back together

Done!

Another poor picture here, but this is what it should look like:

https://cimg3.ibsrv.net/gimg/www.sco...0003a1980b.jpg

Or, pinched from Google (car is watching a video I think):

https://cimg6.ibsrv.net/gimg/www.sco...0c25919ebf.jpg


Well, that's it. Probably doesn't help a single person :D


Just a few tweaks that I have:

- On the Nexus, an application called GMD Gesture Control is installed, this allows custom swipe gestures - I use it for a single control - 3 finger upswipe to bring up the volume bar

**** ESSENTIAL:
- On my Samsung S5, I have an application called Tasker, again just one 'task' used - when my phone establishes a bluetooth connection to my headunit, it automatically creates a wireless hotspot - after which, the Nexus automatically joins to gain internet access. When the bluetooth connection drops, my phone disables the wireless hotspot.

I need a new headunit, I've still got the original (2005) Subaru tape deck head and was using a tape adaptor with jack plug sticking out the front, but that doesn't seem to be working any more.

I have an old Nexus 7 somewhere, and this looks like a great solution, just have a few questions:
What is the USB hub for? Is it necessary?
Does the USB power mean that the cigarette lighter socket can't be used for anything else?
How much total did it cost including all the parts?

The USB hub is used to connect a USB memory stick or anything else USB related - I have used a powered hub so it doesn't interfere with the charging of the Nexus, you could get away with just a USB OTG cable and a USB memory stick plugged directly into the Nexus but it will take away from the efficiency of charging the Nexus, albeit marginally. Or, you can just do without external storage completely!

The lighter socket is still usable, I still use it for charging my phone.

Like yourself, I already had the Nexus lying around, so for all other parts including headunit I'd say it cost me around £60. Don't forget the headunit is a requirement to amplify your speakers, and useful for bluetooth phone calls if supported on the headunit.

Thanks, sounds tempting but I feel even more out of my depth having looked at Timur's Kernel - the wiring stuff was already way beyond anything I've done before with car electrics. Any really basic step-by-step guides you could point me towards?

1. Root your Nexus:
http://www.cnet.com/uk/how-to/how-to...oogle-nexus-7/

2. Timur emails you a step-by-step to install his kernel
His website is explains the functions https://timur.mobi/timurs-kernel-n7-2013/faq/
You want 'Fixed Installation' enabled, this will put the device into a deep sleep when it powers off to retain battery but still ensures a fast boot when powered back on

3. Pull out the centre console, unscrew the fan controls to get a slightly better access

4. Pop out existing cigarette lighter to gain access to the wires; splice into the positive and negative (outlined in my initial post), splice how you see fit - black tape, scotch locks, solder iron and shrink tube is best though!

5. Insert USB charger into new cigarette lighter socket, plug in the USB OTG host cable

6. Attach the Nexus (I've used velcro) to the inside of the console panel, 5 min job

7. Connect Nexus to USB OTG host cable, turn ignition to test it powers on

8. Connect 3.5mm jack cable to Aux in on the headunit

9. Refit everything

Obviously you can have a lot more to it than that, like the USB hub requires modding the power cable so instead of using a British plug it connects to a male USB connector so it can go into the USB charger. The Nexus can be modded to how you want it, I haven't done anything in particular other than customise with Tasker and GMD Gesture (3 finger swipe for volume control). Also it's fully dependant on the headunit you get to power the speakers, if you want bluetooth voice calls etc

Bit later than the original posts 😆
 

https://cimg0.ibsrv.net/gimg/www.sco...708c134eb7.jpg
Only 15 years after original post ive had her 15 years gone from standard import to this 600hp beast