Working on Android Auto with Navigation Unit

Heyo! First post here, I'm currently working on adding the OEM Navigation Unit to my 07' mazdapseed3
which doesn't have that option. However I'm gutting out the screen to put in a portable android auto unit.

So far I've worked out the right unit to use, in my case it's the Carpuride C3; it fits perfectly within the plastic bezels, however requires a little plastic trimming of the existing posts to get it to fit. But the display's bezels fit very well with some fiddling and you can get it perfectly dead center with only a little bit of the screen's bezel showing (a better picture will probably be taken when the display is on because it's a little hard to show on camera).


The unit side of things is pretty easy to understand, it just runs off of your cigarette charger, so if you wire said charger that comes with it to accessory, you've got power unless I'm mistaken. I'd like to retain my oem chargers just because I assume if I wire it in parallel with an existing one, it should be fine right? Even if I draw load off both the screen and if I choose to charge something with it? Some guidance on that part would be appreciated!

But currently my main concern is figuring out the github repo for the arduino code for controlling the motor. Right now there is no wiring diagram anywhere as the guy hasn't documented anything, there has been people in comments and in the main forum post saying they figured it out but nothing in the actual forum and instead you have to ask them... and it's probably going to be a long while until I get a reply. So if anyone has used this arduino code, please let me know!

For context, this is said forum:
https://www.rx8club.com/series-i-interior-audio-electronics-24/my-car-tablet-237158/

Arduino code:
https://github.com/dasonwong/rx8navhood/blob/master/RX_8_NavHood_Control.ino

Attributed video:


I had tried using the original pcb but it's quite bulky when you consider that you need to keep the lcd pcb connected with the other power pcb aswell. But the main thing is I couldn't figure out how to get it powered since I don't have a wiring diagram of the oem harness of what wires mean what. I have the cut harness thanks to whom I purchased it from (Raider)! But I've poked and prodded, but just couldn't get anything out of it after putting in voltage to what I thought would be correct. It's just because I don't know what wires need power, and it seems there's multiple wires that deliver power to this board. Don't forget that the OEM navi connects to the head unit, and the dvd player so the amount of wires isn't exactly obvious but I maybe blind.

Regardless, I believe going the arduino route is the best option so to keep things simple and it gives me a little more to work with since I just have to figure out what the hell the pins are meant to connect to in reference to the oem motor and potentiometer. That is really grinding my gears since I can't tell what MotorDir, and MotorEnable means when it comes to the wires I have. If anyone's got some more insight, that'd be awesome! but otherwise I'm going to just go with trial and error.


There is also a mazda6 navi that also has code written for it however it's a few years older than the RX8 one, aswell as it requiring a separate motor driver with the arduino. The RX8 one uses the motor shield by arduino to accomplish the same thing. However if someone else might be curious, here is the arduino code for the mazda6 navi: https://github.com/amd989/Navi/tree/master

Currently progress is I've got it all taken apart, just need to figure out these damn pin; how to wire it to the oem harness and it should be good to go! If someone could let me know if I could just wire in parallel to an existing cigarette charger, would I still be able to use my oem cigarette charger over that same wire? Thanks!

 

Wiring the 12v port is parallel can be fine but it depends on the total current draw of what you have plugged into both outlets

 

Yeah that's what I was thinking; I'll read the total amperage that I could possibly be pulling but after checking my car, the max is listed to be 120w so about 10 amps. I'm curious if the cigarette lighter infront is wired parallel to the one in the center console

 

For whomever may still be getting their nav unit working with the oem boards, these may help you. Spent an hour trying to scrape the internet to find something like it. I tried wiring the ACC on both connectors to a power supply at 12v, then the negative to ground but it didn't come to life. I maybe a little slow but I did connect the 2 ACC's together at the end of the harness but no dice.

 

I FEEL INCREDIBLY STUPID. I figured out how to get the oem pop up display to work. I finally pieced it all together in my mind from the pinouts I've found online. Confusing myself with the RX8 pinout which apparently is mirrored. For those following along at home, the pins are Q and O from the 24 Pin, and A from the 6 pin. When all of those positive's are spliced together, it'll all just work and the oem display would turn on with a blank screen. I've attached some images to illustrate the wires. The Q is the 4th pin from the right, and O is the 5th. (from this perspective)


I did not know B+ meant positive battery but at least I've figured it out now. I didn't have the actual wiring diagram so it took me a little long to figure out what it all meant... embarrassingly long...

 

Now that I think about it, this might be a little better than the arduino method since I still cannot figure out the wiring, I actually got a response from a person from a forum with his diagram! ...but I have so many questions that my amateur brain cannot comprehend why it is that way. At some point in the future I would like to swap over to the arduino but for now I may figure out an alternative method to make the OEM boards work.

A new reason has came to my head and it isn't because I can't figure out the wiring diagram I promise; when it comes to the illumination of the buttons, I think keeping the original board might be a little better. Since the arduino code doesn't include anything about making the buttons light up, those buttons are also part of that closed circuit so I don't think I can just wire in the positive illumination and have it just work like that... but maybe I'm over thinking it and it may just work properly so long as I can hook it up directly to the middle wire in both of the buttons, the negative is common ground so that part wouldn't matter so long as you connect it to the car's ground.

Regardless, here are the credits for what made me use my big brain for once:
https://www.rx8club.com/series-i-interior-audio-electronics-24/my-car-tablet-237158/page3/


Here is a fantastic thread for someone who made it a whole lot more custom than what I've seen on the internet so far:
https://bluewavestudio.io/community/thread-3766.html
They used a raspberry pi running crankshaft (i think) but modified with their own custom boot screen, shorter bootup from what I can tell from the original crankshaft image, and a stepper motor replacement with PID tuning.

 

Progress:

Mounted the Carpuride C3 by repurposing some of old display's mounting tabs. I just wiggled the tab off and screwed it down to the old posts. Holds surprisingly well! But a better solution would be to have it also screw into the back of the display but as much as I'd like to whip out the 3d printer and take some measurements, I'm just going to leave it as it is since it's pretty solid with just this. If I do print some brackets, with it being PLA it may just break over time and I kind of don't want to go through the hassle of getting a different filament to make these tabs.

The wire you see thats going the long way is the aux cable, I'm doing it this way so that I can try to run a usb extension so that I can also get usb android to work in the car. I might as well since otherwise its a feature that'd be unused unless I route a wire to it.

The old display pcb is going to be sitting ontop of the C3, and one concern for me is going to be heat as this does sit in the dash. The old pcb does block off all the vents that run into the unit, and I can't really think of a better position to put this. I COULD remove trim the bracket that the pcb sits on then mount it ontop of the bucket next to the motor. But I feel alright with this solution, the C3 doesn't feel that hot. I could upgrade the heatsink to be bigger in the unit but that would add more cost for adhesive thermal paste and a larger heatsink. For now, it should be fine.

 

Progress:

The portable android auto unit is in! A better pic of the bezels is attached. The Audio out, dc jack, mic out, and usb is also hooked up and leads out of the pop up display. The only thing messy here is how I did the usb out. The port is usb 2.0 on the unit but I have a 3.0 angled connector out which adapts to usb c, which there is a usb c extension that leads to a female usb c port. I'll have pics of the other end soon when I start getting this mounted to the car. But the wire could certainly be just a usb 2.0 to make it easier but I did not feel like doing some soldering to get the angled port to be longer. Plus I'd have to get a usb A port to fit through the small crevice that the ribbon cable fits through. I'll use some double sided tape to keep the board down and the usb wire. The rest at the other end will be hot glued to keep the amount of play in the wire in the display side the same length.

Some drilling was required on the other end of the flap which will have its photo taken once I got the double sided tape done.

 

Sorry for the lack of updates lately, been doing other stuff while figuring out some things in the car. Right now the display is installed, I had insulated the ribbon cable, and used epoxy to keep the other wires in place so that they wouldnt tug and keep slack in the mechanism. Right now I just finished setting up the AUX since I wanted a physical button to switch between the android auto unit and just direct AUX. This is just my preference to eliminate whatever noise may come out of the unit had I wired directly to the AUX port. Technically you could do that approach and you wouldnt have to drill more holes like I am. But I just wanted something that will be a direct AUX line to the head unit for some better quality whenever I decide to install a subwoofer. There will always be some noise but with this it's just minimized.

For anyone wanting to do this at home, you definitely have options on ways you wanted to approach audio. Could always wire straight into the back of the headunit too.

I've attached some pictures of how it's installed, and I will later make a diagram and some links of how its T'd off from my headunit wires as it looked really busy in the image. The colors are different from what the harness is on the flip up display even though they do the same job.

 

Modification's complete! I'll take some photos later, attach it here; then I'll start making a new thread under How-to's after making some diagrams with more concise information. For now, I am pooped.

 

Some images of the installed unit!
I forgot to show the buttons illuminating at night since at that point I was just excited I changed the boot screen.

In the center console you can see the aux switch and the usb c port that speaks to the unit and can also charge.

 

Nice