Developing a powerful digital looper project for the DIY community

[hoopshot]

I'm kinda pushing the chip's limits right now, and the additional functions I want to add will bog it down even further (meaning less khz), so I ordered an xmega kit which will be MUCH beefier! Only problem is that they're surface-mount only. But the advantages are nice! 32mhz (some people push it to 40 with no stability problems), it's supported by my compiler so porting will be easy, direct memory access, more faster memory, longer loop times, etc! I'll aim for 12bit 22khz top speed.

Did you ever start working with the XMEGA kit? I was looking for inexpensive controllers with larger memory sizes and the XMEGA chips look really good. They also have cheap eval boards, although I'm not sure how you'd use an external audio codec with one.

Thanks,

--Will

[cloudscapes]

Did you ever start working with the XMEGA kit? I was looking for inexpensive controllers with larger memory sizes and the XMEGA chips look really good. They also have cheap eval boards, although I'm not sure how you'd use an external audio codec with one.

Thanks,

--Will

hi Will

I haven't really done anything with the xmega kit aside from making sure I could compile code for it and get a blinking light going. in any case, the compiler and language/environment I use doesn't yet support every feature so it's not yet worthwhile for me. stuff like DMA (though preliminary support was added a couple days ago), and the internal DACs.

so for now, I'm going to finish my looper/sampler with the "lesser" chip.

I haven't looked into how well the xmega will handle 24bit codec chips.

[hoopshot]

hi Will

I haven't really done anything with the xmega kit aside from making sure I could compile code for it and get a blinking light going. in any case, the compiler and language/environment I use doesn't yet support every feature so it's not yet worthwhile for me. stuff like DMA (though preliminary support was added a couple days ago), and the internal DACs.

so for now, I'm going to finish my looper/sampler with the "lesser" chip.

I haven't looked into how well the xmega will handle 24bit codec chips.

Thanks for the info. I was looking for an Xplain evaluation kit and found that they have them at DigiKey for $30.16. These boards have an XMEGA chip with multiple 12-bit ADCs and DACs and 8MB of SDRAM on the board.

--Will

[cloudscapes]

waiting for a PCB is haaaard!   
I'd do it myself but it's double sided, and I want this proto to be reliable. not patched up with jumpers and lifting copper.



basic interface. no graphics yet. no stompswitches as it's meant more as a tabletop looper.

[Taylor]

Awesome. Will you have a second board for the LEDs and pots, or will you wire all that offboard?

...and will this be a DIY-able project?

[Strategy]

How do I get one? 

well done!~

[wavley]

Yeah, I'm totally in to this, my boomerang is giving me trouble with digital noise and ground loops, I'm tired of repairing it (for the longest time it would start recording whenever a loud noise happened, turned out to be a bad solder on a fet)  The only thing I can reasonably replace it with is another boomerang and a can't afford the new one and I feel that nothing else is quite as performance oriented.  I don't care about saving two hours of crap, I might as well be playing with a computer or sequencer and there is nothing rock and roll about that.  This looks really promising it looks like all the features I need to be foot switchable can happen.  I can't wait for the new WTPA to come out and try converting that to a pedal.  You guys rock because my digital skills are marginal at best, I'm an old school tube amp guy.

[cloudscapes]

Awesome. Will you have a second board for the LEDs and pots, or will you wire all that offboard?

...and will this be a DIY-able project?

the 16 leds in the middle will have their own little board and own co-processor.

for this prototype, everything will be hand-wired (I've done worse)
in the future, I hope to have EVERYTHING on a single board. pots and all. save for maybe the jacks.

[cloudscapes]

PCB is done. enclosure is drilled and primed. need to start on paintjob/decal/finish. then, assembly!

[Strategy]

AWESOME! Assuming the project goes forward the way you hope, will you be doing runs of boards etc?
well done
strategy

[cloudscapes]

there is a second (smaller) pcb i naddition to this one. it has the 16 chaser leds in a row and a microcontroller that acts as a 4-to-16 multiplexer.

AWESOME! Assuming the project goes forward the way you hope, will you be doing runs of boards etc?
well done
strategy

I... might....

Not before I redo the board so that everything is PCB mounted. pots and leds. except maybe the two toggle switches. pre-programmed chips would also need to be included.

[cloudscapes]

http://soniccrayon.blogspot.com/2010/12/crushed-glass-granular.html

[Taylor]

Very cool as always. Rick/FrequencyCentral had a tube noise generator called "Crushed Glass" awhile back, funny coincidence.

The noise-beat guys will eat this up when you start making them for sale. 

[cloudscapes]

Very cool as always. Rick/FrequencyCentral had a tube noise generator called "Crushed Glass" awhile back, funny coincidence.

The noise-beat guys will eat this up when you start making them for sale.  

now that you mention it, it does kinda sorta ring a bell..

my brain sort of reads a cool term or word and years later I use it for a song or project, totally forgetting where it's from and thinking it's my own idea.  

sorry rick!

I'll have to restart the code from scratch if I'm to sell a few of these. it has some quirks that I've gotten used to but I'm sure others will dislike. the code is so patched up and hacked that it proved impossible fixing these.

I also think next time I make this sort of looper, it will be a good opportunity to finally learn C and start using dsPICs in a real project.

[Taylor]

Your marketing skills need to catch up with your design skills! In weirdo processor land, quirks are selling points, not problems.  But I do know what you mean.