[Android Head-Units] e.sjolund:
NR5002 Install and DIY Volume+ sub control

Hi all! :D

I´m proud to say that I got my NR5002 installed in the car! It´s taken a long time, not just because I waited to buy the unit, but because I wanted to make this build perfect.

Because of limited forum skills for posting pictures, I´ll then just attach everything.

So without further edu, i would like to introduce my setup. (I´ll do this by parts, as I feel like each part deserve their own spot)

Mounting plate and fascia for Mercedes w203:

This has probably been the part that took the most time. I´ve used hours to create a nearly perfect fascia replica for the NR5002 head unit. I did not like the fact that there was no 8" fascia fot the Mercedes, yet alone that the headunit would stick out and look ugly. I thereby decided to make my own, designing in Solid Works, and printed on a 3D printer. The part itself has been redesigned 2 times, with numerous of changes in between. (wrong measuring is a pain in the a..) The main reason why it took so long time was probably because I was in the state of learning. I had not used a 3D printer before, so it was a learning curve. I also made mistakes, which lead me to further developments. The current version does fit like a glove, just might need some sanding. The curves of the fascia are pretty much aligned and up to my standar. The entire case is made up by three parts. The faceplate, holder, and feet. It was printed on the Flashforge dreamer with ABS, and it was a close fit, I almost ran out of space. The faceplate does have some extra plate that sticks out, but this is because it makes support work better (using flashforges slicer), and can thereby be printed faster. (Using my school printers, so can´t take forever. The print of the faceplate was 20h).

The dimensions are not entirely spot on, because I experienced that the ABS would shrink, thereby making the overall dimensions smaller. This is now fixed and can be adjusted if needed with sand paper.

I´ll upload the parts file and STL files so that anyone who are interested can print their own. Just remember to say thanks and post a picture of your finished product.

I did have to sand down the top of the faceplate and use body filler, but the finished product looks awesome! Real stock I would say!

Arduino controlled Volume and Subwoofer controller:

This project started out with the fact that the Nx5002 does not have any volume buttons/ encoder. I also loved my old setup with an encoder (for volume control) and a potentiometer for the sub. The only problem was that it did not fit my car so good. So I ended up with making this "all in one" interface. The way it works is that the arduino triggers an optocoupler when the encoder is turning. One for up, and one for down. This, along with a resistor in series create a crude but effective "push button" emulator. You can then use the Key editor to set these "presses" to whatever, but in this case to be the volume up, and volume down. I Also manage to use the "PCM" (cant remember the name of the app, but it´s been discussed here on the forum for remapping keys) to use both my SWC volume buttons and my interface.

The other great functionality is that you can control the subwoofer level. The unit does not have an option for lowering the rca outputs. You could get an analog pot to do it, but it´s much cooler and better looking to not have buttons and knobs all over the dash. I also like to adjust the bass, so I can turn it up or down, it all depends on the mood... The way that the interface works is by default to adjust the volume (trigg the optocoupler) then to wait for the button to be pushed, and thereby adjusting the digital pot. The digital pot that I used is a dual log audio potentiometer (DS1807). Oh! The interface also got an RGB led, so that you can have a default set colour (VolumeMode) and it will adjust itself from green - red along with the subwoofer level when in BassMode. The interface also remember the subwoofer level when it´s turned off (EEPROM). It will go back to VolumeMode after 3 seconds or if encoder is pushed again.

I´ll upload all the files including the Eagle pcb file. It should not cost too much, I think a total of 10$. (The DS1807 is the most expensive part). Hope this interface helps some people, it definitely made my car look more stock. I place the encoder where the sigar lighter once was. This was a good spot because i did not need the 12v output, and because it had a clear light ring around it. In other words, perfect for the encoder and RGB (see photo attached).

Quick note, I made a mistake in the Eagle board file. The RGB got a negative common. NOT positive, as most RBG does. Just remember to change the Arduino code so that the output will be HIGH, not LOW. Or, cut of/ redesign the board so that it got a common positive. (that´s what I did since I go the wrong RBG led). You also have to change the colour code, as the values will be mirrored. The DS1807 is MIRRORED, so you have to solder it on on the backside on the board!!!

Layout of the front connector is: (Use the Arduino code to double check)

Encoder pin 1-5 (5-4-3-2-1)

RBG pin Blue-green-ground-red

That´s it folk. Hope some of you found this interesting and useful. I´ll try to post a video off the finished project as I´m in the middle of my finals.

If you got any questions, just ask. I´ll do my best to try to answer, but anyone are welcome to pitch in. :cowboy:

Edit: The app is called PBMC Mappings