PriiDash on MFD - turn the MFD into a touch screen for your car PC

I am so excited to share this latest edition of PriiDash that displays right on the MFD. Here is a picture:

It involves some hacking into the MFD and its wiring. More details later.

 

I was getting tired of the cables running everywhere and also having to take the tablet PC in and out of the car. So I started this project to put the PriiDash display right on the MFD. It is not perfect, especially in terms of the ease of viewing - with a tablet PC behind the steering wheel the display is right along the line of sight while driving, but now the MFD is off to the side and as such much more difficult to get a good view with peripheral vision. Nevertheless the car interior is a lot cleaner now and I don't need to take the PC in and out.

The first mod was to move the OBD Y cable out of the way- it used to stick out next to my right knee. The original OBD socket was popped out of the mount and plugged into a "stealth" Y cable that has a mountable socket and a molded socket. The former was mounted in place of the original, and the latter plugged to the Y cable that connects to the two OBD-USB devices I use for the program.


Dash panels removed to route the cable:


The next comes the big project of modifying the MFD - essentially adding a video input via the rear view camera wires.
MFD came out:



This Russian forum thread has all the details:
http://priusforum.ru/forums/index.php?showtopic=11958
Here is an annotated version of the wiring diagram posted in that thread:

I added one more diode to prevent the "R" gear selection from activating the touch panel relays unnecessarily.

I didn't want to solder directly on the circuit board of the MFD as the Russian author did. So I measured the ribbon cable of the touch panel and bought cables and connectors to intercept the touch panel cable:






I managed to squeeze two signal relays inside the MFD metal shell. Sorry no pictures.

With the EV button and ECT spoofer occupying each of the two available blank panels already, I added the video switch to the same blank as the ECT spoofer:


Wires cut and/or tapped:


and wrapped in silicone tape:


I just realized there is no picture of the touch controller board added to the wire bundle. Sorry. But you get the idea.

Originally I was thinking putting the netbook under the center arm rest, but I found it more convenient to just stick it in the glove box:




Finally some pictures on the road:


Interestingly the volume control overlay still works:


The netbook can be operated directly from the touch screen, no need for mouse or keyboard, except the power button. When I park the car I just close the glove box and everything is hidden.

Overall I am pretty happy with the result.

 

Yes I used 2 DPDT relays:
V23079A2003B301 TE Connectivity | PB1058-ND | DigiKey

I bought the cheapest "4 wire resistive touch panel controller" that I could find on e-bay. It took a long time to ship from China. And it omitted an over-voltage protective diode for the 5V input. The soldering looked sub-standard. But it works - at least for now - and we will see how long it lasts.

I searched the web and installed the latest eGalaxTouch driver:
EETI Driver1
There is a utility included in the package that has options to calibrate the touch panel.

I need to overcome two things before I could use Android. I need USB connection for the OBD-USB device - bluetooth is not fast enough. I also need a C++ compiler for Android.

 

The code is uploaded here:

https://sourceforge.net/projects/priidash/files/2014-04%20MFD%20version/