Volvo Hu-803 Upgrade: DAB+, hands-free, aux
I drive a 2004 V70R with the stock HU-603 unit. During the last month I was installing some updates, such as the PA-300 (4-channel amplifier) and the subwoofer. I also changed the speakers in the doors. It sounds quite nice now.
I bought a HU-803 on ebay, which offers surround sound. This HU would be the basis of this project. As you can see in the attached photo, I already reverse-engineered the interface to the display.
So now I'm able to display anything I want on the stock radio display. Furthermore, I can ready all of the buttons (they all use a single pin and different resistors for an ADC).
My idea is, to remove the cd-changer which is integrated into to HU, and plant my pcb with a PIC18F4680 there. The Pic will handle the output to the display. I may also grab the buttons on the frontpanel to control my pcb.
I can switch between my view and the stock HU view by switch the 12 data lines to and from the microcontrollers by relay.
So the remaining problems would be: Stripping a DAB+ radio and adding it to my pcb, like piggyback. The biggest problem here will be the output of the station's name, or the frequency. My Pic would have to read the signals from the DAB+ unit.
So far, I don't have an idea how to do this easily.
The second problem might be the different frequencies, used in DAB+ standard. As my stock antennae are designed for like 100MHz, and DAB+ using frequencies around ~200MHz, there might be some trouble receiving something at all.
And the third problem would be finding a nice hands-free unit. At first I thought of a Parrot 9100, but again, how do I grab the outputs from the display and route it to the HU's display. Especially when the Parrot uses some graphic lcd.
Do you know a hands-free unit which has a bus for output purposes so that I can tap into there? I also would appreciate some brainstorming on my idea :)