[UPDATE! - 2016, August 21]
If anyones still interested in this, I've rewritten my Arduino code so that its semi-readable. It can be found here: https://github.com/dasonwong/rx8navhood

[UPDATE! - 2015, July 16]
I have replaced the Huawei MediaPad in my Car Tablet set up with a Nexus 7, please see the end of this post for an updated semi-DIY video. I filmed it in 4K!

[Original Post]
Hi everyone! After many months I have finally finished my car tablet project . Basically, I've taken a stock navigation hood and fitted a 7" Huawei MediaPad into it.

Here's a video:

The install involved modifying the inside of the hood to make the tablet fit. There isn't much space in there. I had to cut away the four screw mounting points and also cut a slot at the bottom to fit the tablet. To help those wanting to attempt something similar the dimensions of my tablet are: (Length x Width x Height): 190mm x 124mm x 10.5mm. 190mm is about the limit of what you can fit in there because you also need to allow for the headphone and charger plugs. I had to drill a hole on the side to make space for the charging cable. You should try and find a tablet which is

 

Awesome work, I'm about to take this adventure myself!

 

Very nice mate. Saw your video on youtube earlier and would love to do this myself. Got any instructions for what you needed etc for Arduino? Read half a book on the Arduino today and it looks great! I know enough about the dev side to get it working but not so much about the electronics so any info you gathered would be great if you don't mind sharing?

Also, I've been looking at the new Nexus 7. It's 8mm more than the length you recommend, although in your videos it looks like if I got right angled connectors it may squeeze in? What do you recon?

Cheers,
Adrian

 

 

not too shabby. pretty excellent.

 

Very nice! And effective use if foam!

 

From memory I had about 1/2 a cm on either side for connectors. I was using a right angled headphone connector and it was still too long, I had to shave some of the plastic off the connector. The MediaPad has a separate power connector ie. doesn't use the microUSB which was a bonus, meaning I still had access to the USB for software changes. I can't say that the Nexus 7 wont fit, but I had a difficult time getting the MediaPad to fit already.

Another thing to note with the Nexus 7 is that by default it doesn't go into landscape orientation on the homescreen. I know there's hacks for it, but just keep that in mind.

The electronics wiring wasn't too bad, surprisingly I managed to wire it correctly first go. Here's a some of the websites/resources that I used for wiring, but if anyone wants more detailed info I'd love to help:

Using an H-bridge to control a motor (I changed to a Motor Shield in the end)
Physical Computing at ITP | Labs / DC Motor Control Using an H-Bridge

Tutorial on the Arduino Motor Shield
Arduino Motor Shield Tutorial

Official Arduino Website
Arduino - HomePage

 

Very cool

 

That's great thanks very much

 

Well done, adding this to the list of my future mods.

 

i've got my hood working with the stock pcb and running off of the original plug (modified to just have lights, gnd acc and +12v)

if i simply wanted to use the arduino to control the power supply to the tablet, what would i have to do to get that working?

before i saw this i was thinking off running the cable to a usb car charger connected up to an acc fuse in the fuse box via a fusetap. is the arduino doing the same as this?

 

Your ACC fusetap would work, but it would mean if you decided to close the hood while the engine was on, the screen would turn off due to orientation change via Tasker, and to turn it back on you would have to turn the car off and on again.

Using the Arduino to just control charging is possible but, the difficult part is letting the Arduino know when to toggle the charging (ie turn screen on). I was able to know when the screen was opening or closing because I used the Arduino to operate the motor. I guess a solution would be to use a gyroscope or orientation sensor with the Arduino to detect whether the hood was open or closed. Or you could toggle the charging manually, which was what I was gonna do before my stock pcb stopped working.

Hopefully other members will have better ideas.

/edit Forgot to answer your question about what the Arduino is doing.

The Arduino is always on, it is powered by the +12v battery line, and continually checks if ACC is on or not. If ACC is on then it'll enable the buttons on the hood and restore the hood to its previous position. Whenever the hood is required to 'open', whether by button press or restoring to previous position, while the hood is rising the Arduino will stop charging the tablet. Once its fully opened charging will resume, hence causing the screen to turn on. At all other times the tablet is constantly charging, yes even when the car is off. Hope this makes sense.

 

There is a app that turns the screen on when you turn the tablet back up.

 

Could you please provide a link to this app? It would make life a lot easier for a lot of people. Or did you write one?

From my understanding it isn't possible to turn the screen back on based on orientation change because from Android 2.1 upwards the sensor turns off when the screen is locked. I heard there was a hidden API which could be used but I never looked into it.

 

https://play.google.com/store/apps/d...r.awesomeonoff

https://play.google.com/store/apps/d...otateoffwidget

Need both.

 

The first app seems to use the proximity sensor which would work, but I believe and certainly with the MediaPad, most tablets don't have those.

The second one, by its description, seems to only turn the screen off.

I guess another thing to look for when choosing a tablet is one with a proximity sensor, would've made my life a lot easier.

 

Still wouldn't help it wake up...

 

Sorry guys, I'm new to the android system. But with those two apps my tablet turns on and off when I flip it, even after it's been sitting all night.

 

oh and I'm pretty sure you can adjust what angle it turns on and off.

 

To add my 2c, I think that the app in the first link does indeed turn the device on due to rotation, not by using the proximity sensor. I just tried it out on my Evo Lte and it functions correctly without anything near the phones sensor. Hope it works for you.

 

I'm glad to hear it works! Another option for future tablet installers.

 

just keep in mind that a hook preventing sleep will reduce run time. Whether that becomes a problem or not is dependent on how often and long you drive. At most it'll be an inconvenience at times because you'll have to physically boot the tab.

I bring my tablet in the house every week or two for a full charge because I never have it powered up and charging for more than 40 minutes at a time and it sits all day and night in deep sleep mode.

I'll likely implement contact points when / if I ever wire up my OEM nav. The ardrino solution is nice because you could go even further with something like a 9000+ mAh charging brick in addition to just relying on ACC for power.

 

Wait now I'm confused.

The car charges the tablet why would you need to take it out the car to charge it?
all you have to do is drill a very small hole ontop the power button so you can reboot if needed.

 

wont the proximity sensor be hidden inside the hood thus making the app useless?

surely with tasker you can make the on off action based on usb charging? when charging occurs, screen on, when it stops, screen off?

this would mean that the screen is on when the hood is down though i guess

 

It doesn't use the proximity sensor.

watch the video, you can see it turn on and off when it flips



www.youtube.com/watch?v=cde5BYXYUHw