Opensource hardware CDJ/MIDIPC - Raspberry Pi ($25)

[MiL0]

I received 2x Pi's in the post last week so I'm going to give it a good go... thanks for the heads up

[zestoi]

sounds good i finally got the email from RS supplies a few days ago to actually place an order for one, going to be a while but should be cool. ordered the mini case for it too, neat idea. i downloaded a vmware image the other day too so have a virtual one running here, not sure if its emulating the arm processor or whether it's just an intel build of the rpi setup or something.

i'd be very interested to see if u can get mixxx running on it i remember ryan mentioned on the mixxx irc the other week that he had got one and was keen on getting mixxx to run on it. and if anyone can then he can

[MrPopinjay]

I still want to see if I can get xwax running on one of these

[MrPopinjay]

I've been looking into this for a few months now, ie. having two raspberry pis instead of CDJs running through my analog mixer.

There's also a player called Alsaplayer (or libalsaplayer) that is quite lightweight.

I've installed it on a virtualbox raspberry pi and it works . . however I can't work out how to use many of the features that the software claims to have. I have managed to play music and repitch with accuracy of 1% (nowhere near enough).

The software developers claim that alsaplayer (or libalsaplayer) is capable of:

-pitch accuracy beyond 0.01%
-remote control from other applications (and MIDI control)

Unleashing these features would make this software perfect for the job (except for nudge function), don't you think?

Wow that's really cool! I wanna try that out

[zestoi]

I still want to see if I can get xwax running on one of these

xwax is a lot leaner on cpu usage from what i've read than a lot of apps... def worth a go anyway. just need a mini lcd screen so u can see what you're doing

[MrPopinjay]

That's the idea! Decoding mp3s might be a bit taxing on the system though...

[MiL0]

decoding mp3s should be possible via SoC hardware decoding? if not now, soon... (once we have full hardware support for the GPU in software).

but if it's not yet possible, the Pi's cpu is roughly equivalent to a pentium 2-300mhz which should be fast enough to decode an mp3 I'd have thought...

[MiL0]

also:

http://www.raspberrypi.org/phpBB3/vi...php?f=2&t=4985

and

http://www.raspberrypi.org/phpBB3/vi...hp?f=50&t=8842

[ChEeZeBaLL]

I've been researching this heavily the past few weeks.

I have a Raspberry Pi and I've been trying to think of something to do with it.

A friend of mine has a Gemini CDJ-700 which is a fairly decent Pioneer CDJ clone. My main complaints about it would be that the jog wheel is too heavy, and when quickly back cueing the audio will only speed up to a point and then spinning the wheel faster won't make the audio playback any faster.

The Pioneer CDJ-2000's are the only players I'm aware of that have a link functionality (so that audio can be played from multiple players reading off the same usb stick).

If a knock off player came along that had a jog wheel with the same feel/functionality as a Pioneer deck, with link support, I might actually consider buying it.


This got me to thinking, my Raspberry Pi has 2 usb ports, an audio output, and an ethernet port (the Pioneer CDJs use ethernet cables for linking them together).

The Raspberry Pi would surely be fast enough to play back 1 audio file at a time and support pitch adjustments and scratching (I used to run Atomix MP3 [predecessor to Virtual DJ] on my crappy computer 10 years ago).

I'm really interested in trying to build a basic CDJ style media player (with music coming from a usb thumb drive, although I suppose it'd be possible to connect a CD-ROM drive to the Pi as well) with a Pioneer style jog wheel (touch sensitive top for scratching and moving the side of the wheel for pitch bending), a pitch slider, and a Start/Pause button and a Cue button. Being a trance DJ, those are the only features I ever really use on a CDJ and I think it would be a great starting goal for constructing something myself.

I've been reading up on the differences between using a device as an HID vs Midi device. An HID is much more accurate and has lower latency that using the midi protocol, and using midi would add an unnessisary layer of complexity since this would be a purpose specific device. I've read through a few different tutorials on taking apart an old ball mouse and using the sensors from it with a larger encoder wheel that is the same size as the CDJ jog wheel.

One of the biggest problems for me would be the software. I'd want to use a super slimmed down version of Linux that boots directly into some custom software that would handle all the functions of the player (The software would have no GUI). Apparently with the right tweaks and optimizations it's possible to have an SD card based linux system to boot in a matter of seconds. Perhaps you could use a small single line LCD display (like this one) to show track and time information.

I've been looking at xwax which is an open source lightweight piece of DVS software. It only supports using a time code for play back, but it might be a good starting point for me (I'm somewhat familiar with programming in C and I might try tearing my hair out looking through the source code).

Regarding interfacing the HID hardware with the software and audio programming in general, I have no experience with that at all. Time to start reading I guess.

[Nicky H]

The Pioneer CDJ-2000's are the only players I'm aware of that have a link functionality (so that audio can be played from multiple players reading off the same usb stick).

If a knock off player came along that had a jog wheel with the same feel/functionality as a Pioneer deck, with link support, I might actually consider buying it.

Have you looked at the Denon players?
I think the SC2900 and SC3900 are brilliant - I prefer them to the Pioneer CDj's to be honest and they have the link support.