Hi Domu,
I aggree, I will use endless rotary encoder because I want to avoid "gap" when value change on step parameters.
In my head, I hope to use 4 encoders minimum because some page should have more than two parameters : ADSR for example.
I will keep some synth with ADSR some other with DR or AD like nanoloop does, it sound great, and not every synth need complex envelope.
So some page will have two, some four parameters.
The interface will be based on a mixed of nanoloop and Elektron hardware.
I'd like the treillis to show the "trig" step like any drum machine on 16 step, and to be able to select the active step.
There will be another treillis on the left of the first one which will allow to select :
1.1) ENV", 1.2) Note 1.3) OSC 1.4) VCO
1.2) LFO, 2.2) Filter 3.2) FX 3.4) BPM
1.3) LOAD 2.3) SAVE 3.3) PTRN 4.3) BANK
1.4) PREV 2.4) NEXT 3.4) ? 4.4)?
The Raspberry Pi or I think the Raspberry Pi 2 will handle all the audio processing.
But the raspberry can not handle rotary knob easilly IIRC, and I will have to use an arduino to handle the knob.
The treillis are controllable by I2C and raspberry and arduino could handle it.
I'd like the hardware interface to be managed by the arduino because the duino is really cheap and is design to do this kindo of thing.
The audio and the video will run on the Pi because it will be easier to design, debug and maintain.
If you like stuff like arduino, led and push button, go on this I'd like to see what you could desing with it.
And I'd like to share experience and schema.
I will make it "midi" capable and make picoloop be able to recognize it so a firmware will be done for the duino to be able to talk to the pi and recognize this hardware.
I'm very happy to for this next hardware step 
I will pm my email to see your icon and if they are great I will integrate them.
Anyway, they will be better than this text
From my previous post, I have modified a lot a lot of code, moving stuff...
I have finished the big change on the code base last week.
And yesterday I was able to handle a different GUI view for each synth which was my goal.
It have been a really big work and it's not finished because now I have to make it real and not technically possible.
So now I have to redesign the interface of each synth and if you have idea for picodrum, picosynth, dbopl, don't hesitate, it's the right time, I will do this in the next few days.
Two new software synth are integrated, because It was not too difficult and I'd want more advanced engine.
PBSynth : http://dl.openhandhelds.org/cgi-bin/gp2 … 0,0,6,2867
is integrated , it is an old fixed float synth done by Christian Nowak in 2006, it run on opendingux and PSP, windows, I will have to speedup the code base to make it work smoothly on GP2X. But it works fine on it when I check it.
Cursynth is in integration state, and I'm listening to a pattern made with it right now.
It sound really really great, one the best opensource synth I've heard. But this one will never be able to run in a PSP, dingux or something like this. It eat a lot of CPU but it sound really really great and smooth.
When I have finished the Cursynth, integration, I clean the Gui and I push a windows beta of the result and a song
And this realease one should be really great !!!
Thank you domu and have a great weekend.
