GR-55- Project idea for live control of GR-55 via MIDI

Started by MikeTranch, January 06, 2014, 04:36:17 PM

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MikeTranch

Hi All,

I've learned a ton here on VGuitarForums, and now I'm ready to try to contribute something.  I've been working with Arduino (and smaller cheaper clones) for about a year, and know it pretty well, hardware and software.  Just recently I started working on a MIDI controller project for GR-55.  It's coming along nicely, and I'll soon post more info here and on my own blog and youtube channel.

The gist of my project is a small box within arms' reach, that plugs directly into the GR-55 MIDI in.  There are certainly plenty of similar projects out there, but I think I've got a couple new ideas, and I'd like to gather your ideas as well.

To keep it small, simple and cheap, it won't have MIDI IN or THRU.  It will provide Patch selection, and CC messages, e.g. for Assigns.  The idea is to free up the GK switches for other things that you want to control within a single patch, and give you more expression pedals or switches.  And NO bending down to touch the GR-55 with your hands!

For Patch selection, I'm using a rotary encoder with built-in push switch, and simple 7 segment display.  First dial to the desired patch using the display, then press the button to send the Program Change to the GR-55.  I might also have up/down switches (like the GK Sw1 and Sw2 defaults) and even a numeric keypad.  Your thoughts, please?

For the CC commands, e.g. for Assigns, it will have a few pots and switches, and 1/4" jacks for expression pedals or foot-switches. 

I want to keep the user interface really simple,  for example fixed CC#s: one less thing for the user to deal with.  The GR-55 Assigns let you use any CC#, so no problem there, right?  I know some CC#s must be avoided, like Bank Select, but other than that, it looks wide open?

Besides CCs for Assigns, would there be interest in controlling individual settings?  With the MIDI map in the GR-55, I think that would be fairly easy, even with predefined (fixed) CC#s.

I'd really appreciate your feedback on all this.  How many pots and switches on the box?  How many 1/4" inputs for floor pedals and switches.  OK to have predefined CC#s?  (They could be labeled right on the box :-) 

Oh yeah, for patch selection, I'm planing on User patches only.  (I don't think anyone really uses the Lead, Rhythm, and Other patches, right?)

And finally, does anyone know of a supply for simple, cheap, but sturdy, expression pedal, with just a "pot" and perhaps a switch?  I can do a lot with electronics, but I'm not set up to make my own expression pedals.  I know I could use old wah-wah pedals, but I'd like to come up with something new and readily available.  So far in my searching, the FCV100 takes the prize.  It's got some issues as a volume pedal (tone suck from passive PUPs, and excessive noise), but as an expression pedal it's not bad (not perfect with such a large angle of motion, but that's manageable in software.)  And for about $30 it's pretty hard to beat!

So that's my idea folks.  What do you think?

Elantric

#1
* I think its impossible to design a "one size fits all" product - particularly when a chassis and metal work is involved, which typically force you to pass on to the customer a higher shipping cost.
So rule #1 - be sure it fits in standard flat rate USPS priority mail shipper bag/box

I get a lot of small interfaces shipped to me in nothing more than the large USPS envelope seen here:


* The GR-55 has specific finite MIDI CC# range - all covered here:
GR-55 FAQ: Build GR-55 Control Assignments
https://www.vguitarforums.com/smf/index.php?topic=4006.msg34962#msg34962
Here are ALL available  MIDI CC# commands the GR-55 will respond to (observe the gaps)
MIDI CC# 1-31, 64-95

 
* I need a MIDI controller that can talk to my other gear so the rest of my suggestions below are probably out of the scope of your project.

- so I would prefer a box with five  5 pin DIN MIDI Outputs (integrated MIDI Thru box) , for each "patch" have the ability for the user to assign/create 5 separate MIDI output streams  - with user defined MIDI channel, MIDI CC#, Latch  / Toggle,, RPN, NRPN, Sysex - it seems the old 1988 era Digitech PMC-10 had the best MIDI implementation.
http://www.loopers-delight.com/tools/PMC10/PMC10.html


But of course this may be overboard - and sounds like it needs a USB port for user Editor / GUI - like a UNO FCB Editor.

Id really like to put some time on completing the effort Gumtown started with his small guitar mounted Wireless MIDI controller

https://www.vguitarforums.com/smf/index.php?topic=10204.msg73874#msg73874


gumtown

I will definately pickup again on the Wireless controller project,
My work load has now reduced down from the level of 'impossible',
will buy a new PIC programmer as the last one 'failed',
will purchase a Hi-Tech C licenece, as the demo period expired and the free version don't allow code compacting required to fit data inside the chip.

The floor controller on it's own is worth pursuing, as a midi programmable controller,
allowing pushbuttons or variable controlls (knobs or EXP pedals) to be added as wished, and programmed independantly as
program change on any channel, cc# data sending, midi note on/off, and other midi related commands (start/stop/resume/reset).
With 8 digital and 6 analog inputs, midi in and out with thru.
The software editor is already done for it, for mac, windows and linux.
http://sourceforge.net/projects/grfloorboard/files/VGWC-Edit/

It uses a regular PIC16F869
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

MikeTranch

Thanks Elantric! Yeah my goals are modest, just a simple extension of the GR-55 to give more CTRL switches and EXP Pedals.  And free up the GK switches, by providing a rotary patch selector similar to the dial on the GR-55.  I don't plan to have any built in "patches" so no need for an editor.  Just plug and play, simple, small, easy to pack, setup and use on the fly.  This isn't meant for pro use, just another open source project for DIY makers.  I'll probably go with the Arduino Nano, as it has 8 analog inputs.  My target is $75 in parts, not including the optional expression pedals.  (And I know I could get an FC1010 for under $150, so this is more about making it small and simple rather than saving a lot of money.)

Since the GR-55 has only 8 Assigns, I would need at most 8 switches and/or 8 pedals, is that right?  I'm thinking 4 small push buttons on the box, with four 1/4" jacks for stomp switches.  Likewise, say 4 small linear pots on the box, and 1/4" jacks for expression pedals, e.g. FCV100 in CV mode.  (Most of my user patches are already using 3 or 4 Assigns, using the GR-55 controls.)  One downside I see is potentially a lot of 1/4" cables.  But I think as a practical matter, I'd have one expression pedal.  Not sure how many stomp switches I'd actually use.  I think the switches will be momentary, since I can get toggle behavior in my software, or in the Assign.

Since the box won't get stepped on, a plastic project box should suffice. 

WRT expression pedals, I'm leaning towards CV type.  Those seem to be standardized, 0 to 5V.

Are there other pedals available out there for DIYers?  I.e., just the mechanics and a pot and toe switch?


Elantric

Quotesay 4 small linear pots on the box, and 1/4" jacks for expression pedals, e.g. FCV100 in CV mode.

Most of us already own several Expression pedals that comply with the Roland EV-5   / FV-300L (or compatible  like MAudio EXP)


These are simple 10K linear pots  - VR1 is the Pedal Pot, VR2 is the optional Minimum Volume side knob

http://www.soundonsound.com/forum/showflat.php?Cat=&Number=1077329&Main=322584.

Why?

Because the Behringer FCV100 Voltage Control outputs a DC Control Voltage  output which is arcane and seldom used by guitar FX.

Also IMHO the FCV100 is a big pedal - I can fit three EV-5 pedals in the same floor space as 2 FCV100's.

And most of us already have several EV-5 (or EV-5 compatibles by Proel) in our gear box.

MikeTranch

Great advice, just what I was looking for, thanks.  I'll check out those pedals.  They'll actually simplify my design.  I just happened to have the FCV100, bought as a volume pedal, and noticed the CV mode afterwards. Apparently that's more of a keyboard type control.