Tablet install to replace sat nav (Build thread)

[danmiddle2]

For anyone else interested, there are some details on a very similar user interface here (about half way down):
http://www.mp3car.com/show-off-your-pro ... diy-2.html

It appears to be a wallpaper with transparent widgets / launcher icons. Just had a play and managed to re-create something not entirely dis-similar. For now I think I'll be sticking with Dashdroid, but very interested to see what you come up with igeak691

For me, something like Dashdroid with a BMW-looking skin would be ideal.

[NeilP]

Well that's a forum I haven't frequented in a long time!

I miss the good old days of a car pc running cetrafuse on top of windows xp.

[sk93]

Also sk93, if you have your phablet with the battery still in it, aren't you worried that the heat will kill the battery over time making it expand and possibly burst/bust something? That's the main reason I am removing the battery altogether. The car gets way too hot in the summer for me to comfortably leave any lithium based battery inside the car at those temperatures.

As for boot time, this tablet will be on 24/7.. it will go into deep sleep if in face down orientation so that it only consumes a few watts. Boot time ends up being a nonexistent 2 seconds. After the screen turns on, it will be set to automatically play from pandora, but open up the app torque (of course all these settings can be customized after the installation).

I am concerned about the heat, but not overly..
my question would be how long could you realistically leave the phablet on a "live" connection, with the car turned off, before the car battery would die?
I know it's not a question of hours, but it's often the case I can leave my car for a good couple of days (maybe even two weeks) without it starting.
what I'd hate to do is come back from a holiday to a dead car battery!


In regards to removing the battery entirely - what sort of voltage / current is required do you think?


next question is how are you going to get it to wake from deep sleep?
tasker and the like can do it, but only on certain triggers.
the movement sensors are disabled by android when in deep sleep, so tilting is out of the equation.
I also can't get it to turn on via bluetooth.


If you've got some tasker profiles I could steal, I'd be very, very happy!

[chriswoodward]

Just for those worried about battery life, this is quite a common mod for an RX8 and I had done it to mine using a Nexus 7 Tablet, I never had any problems with the battery.

This thread may have some useful info, obviously not the same car but handy for power info etc

http://www.rx8ownersclub.co.uk/forum/vi ... nexus+7%23

[igeak691]

danmiddle2 yes that's where I got the UI from. I think it looks a lot better than dashdroid. It's definitely a workaround like I said and not just a different launcher. With some software tweaking it can be made to look like stock.

sk93 I am using a 12v to 5v convertor that handles up to 15w. That's more than enough juice that the tablet can be using at any moment. I've even seen people using 5v 2a with no issue but I figured overkill is better than under.

Waking up from deep sleep is easy with tasker. You can set it up so that it keeps certain sensors on even when android is asleep. For me, it'll be the proximity sensor that gets used so that the screen is off when the screen is down, but turns on when the screen is up. If it ever turns on while I have my hands touching the screen, I'll just have to use the accelerometer instead so the tilt axis will turn it on (I will see which one works better and report)

I can post up my tasker profiles after I work out all the tweaks. I've been playing with it for my nexus 5, and certain things are buggy so will have to see how it fares when the parts arrive.

[sk93]

I'd be very interested in them!

Interesting to find that you can keep the sensors on during deep sleep... I don't seem to be able to figure that out!

Also.. tasker seems to be confusing my device, as I turn on airplane mode when it "powers down" and off again when it comes back alive.
however, it never finds signal again after it's been in "deep sleep"... only after a hardware reset does it find signal again.. DAMN annoying

[igeak691]

Under preferences, if you go to monitor, scroll down until you see "Display Off Monitoring". If you want it to check, for example, the light sensor even when the screen is off, just click yes. Have a blast!

But you're right, tasker does have some flaws.. I'm slowly but surely finding them and looking for workarounds. There are usually a few solutions to each problem, some better than others.

So.. about that stepper motor. Any idea for a plug and play option that flips up the screen when the car is on? The extent of my knowledge would be soldering, programming right now is out of my league but may learn if I get tired of flipping the screen up and down myself. Also makes for a cleaner installation of course.

[sk93]

Absolutely!

It does involve using an Arduino board tho, but I can provide the programming

All you need is a 12v relay, the Arduino and a couple of bits of wire.

You'd hook the 12v relay up to the +12v antenna remote wire that comes out of the back of the headunit.
This only provides voltage when the headunit is on, so it's a perfect switch.
The other side of the relay would be used to bridge a spare pin and a ground pin on the arduino.

This circuit would mean that when the radio is on, the relay would close, bridging the two arduino pins.
This is detectable in arduino code, so then it's just a case of running the code to open the stepper motor.

This would would doubly well for us, as when the ignition is cut, that is also detectable by the Arduino, so you could then
fire off the code to close the stepper motor

I already have the working code to open, close and "step" the screen in either direction, and that's all hooked up to the four screen buttons.
So coding it to check for voltage across a pin and either closing or opening is pretty easy

[danmiddle2]

wrt to cooling - this is enough to keep mine cool (a fan and some reflective foil tape!):



The fan takes power from the Arduino, so it is trivial to do this.

In terms of the opening and closing, I have now got mine so that it activates from the ingition live, and moves the screen to the last position it was in. Behaviour is now that when I turn off the ignition it closes and when I turn on the car it goes to last position (including any separate steps to angle it).

I am trying to figure out how to make it as smooth as the OE unit.

I will get around to updating the howto at some point....

As for the UI - I don't disagree that this looks better, but offers less flexibility for rapid customisation options over Dashdroid. Ideally I would like both

[sk93]

I've got mine running as smooth as OE..
I believe I dropped the delay between the steps to 50ms?
I'll doublecheck and post up my sketch when I get home, but it's damn smooth.

[igeak691]

Thanks for all that info.. what kind of arduino board would I buy? I suppose I would also need the stepper motor accessory board to hook it all up.

[danmiddle2]

Thanks for all that info.. what kind of arduino board would I buy? I suppose I would also need the stepper motor accessory board to hook it all up.

I went with:
Arduino Uno R3 and Arduino Motorshield R3

[danmiddle2]

I've got mine running as smooth as OE..
I believe I dropped the delay between the steps to 50ms?
I'll doublecheck and post up my sketch when I get home, but it's damn smooth.

That'd be handy, thanks. I didn't realise how "jerky" it was until I finally saw an OE screen installed recently.

[McKoval]

Ok, maybe a silly question, but whixh headunit are you using for the conversion?
The one installed with the satnav (without lcd), or the professional HU with lcd?
I wanted to buy satnav eversince I bought the zed, but the cost for a dated system puts me off quite heaviky.. but if I would be able just to buy a flipscrren and a tablet I would probably consider cutting the dash

TapaTalking

[sk93]

I'm using a BMW Business Headunit.
Never had the oem satnav and never wanted it.