DAB integration?

Raspberry Pi related support

DAB integration?

Postby daviestar » 31 Mar 2016, 14:05

Hello,

I'm researching the best fit for a car audio project, and came across RPI/Digi+/headless Rune Audio as a possible candidate (main concern is optical out to feed into a Audison Prima AP8.9). From what I've read I can easily have a large music library and high bit-rate digital output with this setup, using a phone/tablet for UI :D

Has anyone been able to integrate DAB into a RPI, and get even basic support through the Rune Audio UI? If so, what DAB tuner did you use, dongle or board?

I'm a web developer and understand there are complexities integrating DAB with the UI - track names, signal etc would need to be updated using web sockets. However I only ever listen to one radio station! So I'd be perfectly happy setting the DAB tuner up and tuning through CLI then just having the basic ability to switch from music library to DAB and back again through Rune Audio UI.

Does anyone have any experience of this and can point me in the right direction?

Thanks, Dave
daviestar
 
Posts: 16
Joined: 31 Mar 2016, 13:42

Re: DAB integration?

Postby chsims1 » 01 Apr 2016, 08:18

This isn't an answer to your question, but a pointer to someone else asking a similar thing. https://volumio.org/forum/want-add-dab-radio-receiver-t3949.html
chsims1
 
Posts: 5
Joined: 03 Mar 2016, 11:44

Re: DAB integration?

Postby daviestar » 01 Apr 2016, 13:47

Thanks for that, I'll post over there too :)

There are a few DAB radio solutions for RPI. This dev board has a C-based UI. This one is pricey but appears to have a lot of resources to help a n00b like me.

I don't know much about C or electronics/hardware (hoping to learn a bit with this project!). What general steps would be involved to bring that C touchscreen interface to a PHP app? The bit that is very fuzzy for me is getting the DAB hardware to communicate with PHP - after that I should be able to take it from there.

If anyone with complimentary skills is looking for a project - as part of Rune or standalone - I'd be happy to contribute the UI side of things! Don't mind which hardware is used as long as it works and can accept an external aerial (exterior car DAB aerial).
daviestar
 
Posts: 16
Joined: 31 Mar 2016, 13:42

Re: DAB integration?

Postby Dohmar » 02 Apr 2016, 16:44

I received my DAB dongle last week but haven't had much of a chance to test it. I'd need to have the drivers for the stick compiled in the kernel which will be my first step when I get a day or two free, then compile a version of sdr-rpi

Will post results when I can

-D
Dohmar
 
Posts: 79
Joined: 14 Mar 2016, 12:27

Re: DAB integration?

Postby daviestar » 02 Apr 2016, 23:48

Thanks Dohmar, I'll be eagerly awaiting your update :)

Which dongle are you using?

Over the last few weeks I've been researching car audio with one good D/A conversion. The aftermarket situation is very strange in that there are plenty of good DACs, but almost no head units with digital outputs! Car audiophiles are using iPads connected wirelessly to Airports to provide optical out at 96kbps.

I started looking for DAB radio's outside of car audio, portable and separate, and found very few with a digital output. Am I thinking about it the wrong way? Isn't DAB radio a digital signal, meaning in theory it should be easy to provide a digital output? Or because it's still a "radio" does that mean the signal is actually interpreted as analog by the "tuner"? (I use parentheses here to highlight my stupidity :)) If this is the case, maybe I should be less concerned with optical out from DAB, if it needs to be A/D converted to provide digital output.

The best portable DAB radio for in-car use I've found is the Technisat DigitRadio 110, in case anyone is interested.
daviestar
 
Posts: 16
Joined: 31 Mar 2016, 13:42

Re: DAB integration?

Postby Dohmar » 08 Apr 2016, 04:02

daviestar wrote:Thanks Dohmar, I'll be eagerly awaiting your update :)

Which dongle are you using?

Over the last few weeks I've been researching car audio with one good D/A conversion. The aftermarket situation is very strange in that there are plenty of good DACs, but almost no head units with digital outputs! Car audiophiles are using iPads connected wirelessly to Airports to provide optical out at 96kbps.

I started looking for DAB radio's outside of car audio, portable and separate, and found very few with a digital output. Am I thinking about it the wrong way? Isn't DAB radio a digital signal, meaning in theory it should be easy to provide a digital output? Or because it's still a "radio" does that mean the signal is actually interpreted as analog by the "tuner"? (I use parentheses here to highlight my stupidity :)) If this is the case, maybe I should be less concerned with optical out from DAB, if it needs to be A/D converted to provide digital output.

The best portable DAB radio for in-car use I've found is the Technisat DigitRadio 110, in case anyone is interested.


Hi Davie,
I have a RTL2832U + R820T2 Mini DVB-T + DAB + FM USB dongle. They're the most common on ebay and they cost around $10 including delivery! Nice and cheap!

DAB is digital, correct, however when considering the manufactured radios, internally it has its own DAC which converts to analog.
The DAC conversion happens after the tuner, so the tuner itself sets a frequency and the output is simply piped into a DAC.

A commercial DAB looks like this
Radio signal -> Antenna (Picks up radio signal) -> Demodulator -> DAC -> Amplifier
The tuner in this case directly controls the demodulator

On a pi, this is how it would be done
Radio signal -> Antenna -> Demodulator) -> USB -> Pi -> DAC -> Amplifier -> Speakers
The tuner in this case is controlled via software on the PI which then controls the Demodulator

The current issue I've got is driver support, I haven't gotten around to compiling a replacement kernel, and am hoping the devs here can incorporate the drivers in the form of a loadable/unloadable module. The whole Software defined radio is what makes this thing possible though it might take some doing to get working (I'm experienced with linux but arch seems to be quite different to slackware).

For using a PI, there are pi Hats that have optical digital output, and then whatever you're feeding that into does its on digital to analog conversion, that would be my recommendation if thats the solution you're after. I personally use the x400 from suptronics as my DAC and amplifier combo, but that probably wouldn't suit a car as it only has stereo outputs and rca out for a subwoofer (You'd need to have another amp or self powered/active rear speakers for more than 2 speakers in the car)

rpi-dac seems to be the best software solution so far as it is tailored for the pi and talks to MPD, I think via ALSA api but perhaps it can be configured as a source for MPD. I'll have to work on that for a bit I think, as there is no binary for ARCH linux and the source code won't compile for me - havent yet had the time to get back into it, I might be able to this weekend.

Will keep you all posted. I've requested the kernel have the drivers added for the next 0.4 release in the feature request part of the forum.

-D

** Edit ; I had some time to screw around with the pi tonight, i installed rtl-sdr via pacman and that detected the usb stick using the test software so drivers might not actually need to be compiled in. sdr-j is the other software that talks to rtl-sdr and then pipes the DAB/FM audio to something like ALSA or MPD, still not sure on the mechanism
Last edited by Dohmar on 08 Apr 2016, 13:06, edited 4 times in total.
Dohmar
 
Posts: 79
Joined: 14 Mar 2016, 12:27

Re: DAB integration?

Postby hondagx35 » 08 Apr 2016, 12:57

Hi all,

the latest RP2/RP3 image has support for RTL2832 and R820T included.
Here the output from dmesg after plugging in a RTL2832U + R820T2 Mini DVB-T + DAB + FM USB dongle.
Code: Select all
[  352.634674] usb 1-1.3.3: new high-speed USB device number 14 using dwc_otg
[  352.746645] usb 1-1.3.3: New USB device found, idVendor=0bda, idProduct=2838
[  352.746669] usb 1-1.3.3: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[  352.746684] usb 1-1.3.3: Product: RTL2838UHIDIR
[  352.746699] usb 1-1.3.3: Manufacturer: Realtek
[  352.746712] usb 1-1.3.3: SerialNumber: 00000001
[  352.816752] usb 1-1.3.3: dvb_usb_v2: found a 'Realtek RTL2832U reference design' in warm state
[  352.871559] usb 1-1.3.3: dvb_usb_v2: will pass the complete MPEG2 transport stream to the software demuxer
[  352.871639] DVB: registering new adapter (Realtek RTL2832U reference design)
[  352.896647] i2c i2c-3: Added multiplexed i2c bus 4
[  352.896677] rtl2832 3-0010: Realtek RTL2832 successfully attached
[  352.896741] usb 1-1.3.3: DVB: registering adapter 0 frontend 0 (Realtek RTL2832 (DVB-T))...
[  352.919081] r820t 4-001a: creating new instance
[  352.931020] r820t 4-001a: Rafael Micro r820t successfully identified
[  352.943721] media: Linux media interface: v0.10
[  352.965079] Linux video capture interface: v2.00
[  352.988395] rtl2832_sdr rtl2832_sdr.0.auto: Registered as swradio0
[  352.988422] rtl2832_sdr rtl2832_sdr.0.auto: Realtek RTL2832 SDR attached
[  352.988438] rtl2832_sdr rtl2832_sdr.0.auto: SDR API is still slightly experimental and functionality changes may follow
[  352.995178] Registered IR keymap rc-empty
[  352.995688] input: Realtek RTL2832U reference design as /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.3/1-1.3.3/rc/rc0/input2
[  352.996037] rc0: Realtek RTL2832U reference design as /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.3/1-1.3.3/rc/rc0
[  353.012095] IR NEC protocol handler initialized
[  353.016067] IR RC5(x/sz) protocol handler initialized
[  353.021133] IR JVC protocol handler initialized
[  353.021647] IR RC6 protocol handler initialized
[  353.024404] IR Sony protocol handler initialized
[  353.029777] IR SANYO protocol handler initialized
[  353.036198] usb 1-1.3.3: dvb_usb_v2: schedule remote query interval to 200 msecs
[  353.038293] IR Sharp protocol handler initialized
[  353.039194] input: MCE IR Keyboard/Mouse (dvb_usb_rtl28xxu) as /devices/virtual/input/input3
[  353.039958] IR MCE Keyboard/mouse protocol handler initialized
[  353.044493] IR XMP protocol handler initialized
[  353.044543] lirc_dev: IR Remote Control driver registered, major 242
[  353.047606] usb 1-1.3.3: dvb_usb_v2: 'Realtek RTL2832U reference design' successfully initialized and connected
[  353.047929] usbcore: registered new interface driver dvb_usb_rtl28xxu
[  353.048971] rc rc0: lirc_dev: driver ir-lirc-codec (dvb_usb_rtl28xxu) registered at minor = 0
[  353.048994] IR LIRC bridge handler initialized


Frank
User avatar
hondagx35
 
Posts: 2990
Joined: 11 Sep 2014, 22:06
Location: Germany

Re: DAB integration?

Postby Dohmar » 08 Apr 2016, 13:08

hondagx35 wrote:Hi all,
Frank


Thanks Frank, it looks like you're right, I was able to run rtl-sdr on the pi and it seemed to talk to the stick OK.
I was wondering if you could provide me some tips on how to build sdr-j on arch linux for arm. I'm familiar with using ./configure and make to build source under slackware but I have no idea how to do it on arch.

Also, I don't have a bunch of money but I'm happy to buy 3 more dongles and post them to developers of Rune audio if they would be able to help me get this working. They cost around $10 each so its not a huge expense, I figure though the postage internationally might be as much.

I can do some of the stuff, mostly documentation and beta testing, but someone would need to make changes to the gui, integrate the changes into the main tree and define the command line stuff within the webui

Thanks
-D
Dohmar
 
Posts: 79
Joined: 14 Mar 2016, 12:27

Re: DAB integration?

Postby daviestar » 08 Apr 2016, 14:59

I'd be happy to contribute - submit pull requests to your github repository for someones approval, or whatever way you guys prefer to work - for DAB proof-of-concept too.

Many hands make light work!

Cheers, Dave
daviestar
 
Posts: 16
Joined: 31 Mar 2016, 13:42

Re: DAB integration?

Postby hondagx35 » 08 Apr 2016, 15:21

Hi daviestar and Dohmar,

I can do some of the stuff, mostly documentation and beta testing,


'd be happy to contribute - submit pull requests to your github repository for someones approval


Sounds good, so let me make some further tests.
We also need some good ideas on how to integrate this in the UI.

For the first tests i would like to clone the repo and a make a separate branch for now.

Frank
User avatar
hondagx35
 
Posts: 2990
Joined: 11 Sep 2014, 22:06
Location: Germany

support RuneAudio Donate with PayPal

Next

Return to Raspberry Pi

Who is online

Users browsing this forum: No registered users and 4 guests
cron