Next level midi performance controller project

[VFXcompositor]

Hi all! I'm thinking about buying a midi cpu and finally willing my idea for a next level performance controller into existence and would love to have a little bit of insight from the pros around here on my plan. I've attached two images of my layout idea one with text for components. all the buttons should be fine as momentary buttons. but if its not super hard to get latching buttons with little leds in them for some of the buttons, that would be very cool. pots/faders should behave like normal pots/faders. but the really cool and funky thing on this deck would be the big scratch wheel/midi turnable, which i think i can just do with a nice quality rotary encoder? (i have this one in mind... am i totally off base? - http://www.automationdirect.com/adc/...29/TRD-S360-BD ) in total i believe I'd have 38 buttons, 12 pots, and one rotary encoder.

So... what do you guys think? any suggestions/comments etc... I'm a pretty savy dude but i've never done anything this in depth before. If you could recommend a good place for quality parts (pots, faders, encoder, wires, anything else i might need..) i'd be greatly obliged. I'm a producer,videographer,post-guy,dj,bassist,flash,java,html,php coder by trade so i should be able to swing the sysex stuff no prob with a little help But i havn't soldered anything up in a quite a few years so i could use some pointers.... haha!

Anyway, let me know what you think! I promise to post pictures & vids throughout the build and whatnot so your awesome advice/comments won't go without some sweet img-candy to ogle at lol! seeing suggestions and advice become reality is always the coolest thing

[bzl]

To start with, that amount of buttons and things is too much for one midi cpu and you'd need to use two. It's not really much more difficult than one (you can chain them together) but it is some extra work and expense.

That encoder seems like super overkill and you ought to be able to get one that works for you for about a dollar or two, I think. Some of those electronic parts suppliers sell things for applications like hospital equipment and military hardware, where everything is way overpriced-- you'll want to avoid that stuff because your midi controller probably doesn't need a hundred million dollar insurance policy in case it fails and someone dies.

Seems to me that the key in picking an encoder would be its sensitivity: if you turn it through 360 degrees, how many times does it "pulse"? I think you'd have to do some testing to find out what feels right, or do some research and see if you can find out what similar commercial products do. (Or maybe Ableton or whatever can adjust for different sensitivity rates? I have no idea.)

Anyway I like to get parts from Jameco (cheap but limited selection) or Mouser (phonebook-sized catalog but more expensive and some of that is eight cent resistors priced at $800 each for government contracts).

[VFXcompositor]

right on thanks for the pointers man! i'm fine with another board if it has to be on there. how many buttons would I need to remove to get it all to fit on one? I thought I had it so it might fit.

I know that encoder is super overpriced and still looking for alternative. but its the only one I've found that has 360 pulses per one revolution. seems like that would be perfect for a midi turntable.

[John]

Hi VFXcompositor, welcome.

Looks like a cool project.

If you'd like to discuss how you might build the project using a MIDI CPU, please make a list of MIDI CPU control terminals 0-23 and your proposed function for each. From there, we can discuss the wiring & configuration strategy in more detail.

- Encoders require 2 terminals each.

- Analong inputs (like pots or faders) require 1 terminal each.

- Switches can be matrixed using s + d control terminals, where the total number of switches = s x d. s and d stand for select and data.

For example, a 4 select x 8 data matrix (4 + 8 = 12 control terminals), you can connect up to 32 switches (4 x 8 = 32).

[VFXcompositor]

Thanks John!

Ok, so I'm still on a parts hunt. but heres what I have so far:

terminals 0 - 1: rotary encoder for turntable
terminals 2 - 13: pots/faders
terminals 14 - 23: buttons

[bzl]

I think that 360 pulses/rev is gonna be way too sensitive; that thing will be triggering every time you look at it funny. I'd try something like 20-24 to start with. I know it doesn't seem like much but you can get those for really cheap and it might even work. If not it would at least give you a good idea of how much more you'd need, so you don't go buying any $90 parts unless you absolutely have to.

Like John said, if you cut a couple of pots it will buy you a lot more than cutting out buttons. For example, you could do ten pots and the encoder and you would have twelve terminals left for 6x6=36 buttons. That's about as close as you'll get to your design without adding a second CPU.

[VFXcompositor]

I think I understand you bzl. I made a couple of adjustments to accommodate using just one midi cpu since i was so close to the limit. I've attached the new v2 layout image below.

terminals #0-1: 1 encoder
terminals #2-11: 10 pots
terminals #12-23 : 36 buttons

I've also added a spot for power and MIDI activity LEDs on the deck as well

Found some much more reasonably priced parts so I'll post those once I have them compiled too

[VFXcompositor]

Alrighty, so below we have the v3 layout. I think i'm pretty solid on this one. was re-working a bit of functionality and how the deck would actually be used and I think i've arrived at a decent solution.

Basically the left side 16 button bank w/ cue/loop is a virtual deck-A, and the right side rotary encoder, 7 button bank w/ cue/loop is a virtual deck-B. the 6 pots and buttons at the top are for global effects. the 2 pots and buttons above the rotary encoder are for vinyl emulation control.

I also found a handy & cheap little "uh-oh" battery level kit at sparkfun.com that I want to wire in so I can run the whole thing off of a 9 volt battery and not have to plug in more stuff over my tables.

I'll post my parts list in a couple. in the mean-time, any thoughts? after looking at a couple wiring diagrams I think i'm finally understanding the switch matrix thing lol

[VFXcompositor]

v3 layout img

[VFXcompositor]

So heres my list of prospective parts finally... still doing some re-arranging but wondering if theres any glaring incompatibilities as its quite late an just been hackin away haha

rotary encoder:

http://www.mouser.com/ProductDetail/...bT4aLOCGMWM%3d

http://www.mouser.com/Search/Product...L12S4025FN4024

http://www.sparkfun.com/products/10984

buttons:

http://www.mouser.com/Search/Product...07-PS322SUY-EV

https://www.jameco.com/webapp/wcs/st...oductId=155380

http://www.sparkfun.com/products/9338

Crossfader slide pot:

http://www.sparkfun.com/products/9119

rotary pots:

http://www.sparkfun.com/products/9941

other components:

board? - http://www.sparkfun.com/products/8619
wire? - http://www.sparkfun.com/products/10647
this thing? - http://www.sparkfun.com/products/11087
ok i can handle this - http://www.sparkfun.com/products/91


let me know what ya think =]

also quick quistion... does anyone know is there is any trouble mapping a rotary encoder to something that a modulation wheel is normally controlling? just sort of wondering if it normally snaps around or waits till you come back or just bounces or what lol im sure i'll figure it out =]

Thanks!

[Jim McDougall]

Two comments

1) Look for a regular 5k linear slide pot from mouser or Digikey -- the referenced pot is not a true linear taper.


2) The buttons from jameco and mouser are about 0.5 inches across.
The sparkfun buttons are 1.375 inches in diameter . Probably way too big and a real pain to drill mounting holes that are over an inch in dia.

For reliability, I'd probably use the bourne encoder.

[VFXcompositor]

Thanks for the pointers Jim!

yeah honestly the biggest issue i'm facing now is how i'm going to secure all this stuff into a solid enclosure that can take a bit of a beating. Not super rough or anything but it's a performance controller and I tend to pound on my decks when i get into it haha! I see what you mean about the arcade buttons though, those are not going to fit on anything reasonably sized. and I need to have room for the 8-12 inch midi turntable on the right. most enclosure's I've found are no bigger than 10 inches... I was standing in the kitchen this morning and started looking at all these cookie sheets with big ideas... they're just the right size and i could stack two with spacers in between and nibble holes for the controls... could be hair-brained but that might just work...

[VFXcompositor]

would this be an acceptable slide pot for the crossfader?

http://www.mouser.com/Search/Product...L60-15G1-502B2

[VFXcompositor]

just thought of something else. with this encoder : http://www.mouser.com/ProductDetail/...bT4aLOCGMWM%3d

it says supply voltage: 5V, If im powering the midi cpu off of a 9v battery/9v power supply, will I need to throw a resistor in there for the power to the encoder? does the encoder even need power? in all the wiring diagrams if looked at so far with the midi cpu the encoders just need a ground and the two channels hooked up.

Also, i'm debating on whether or not i want to put LEDs on all the buttons. How big of a deal is it in the long run to add LEDs to the buttons to indicate their status? Is it even possible with 36 buttons in a matrix? so like ideally the led wired to a button would light up quick when pressed if it was a momentary, and stay lit if it was a toggle.

any thoughts/input would be awesome

Thanks!

[VFXcompositor]

also, how necessary are the diodes? & would these work? - https://www.jameco.com/webapp/wcs/st...roductId=36038

[Jim McDougall]

The 1n4148 diodes will work just fine and yes they are required ! As to voltage --- all devices such as the encoders get their 5V from the midiCPU board not directly from the power supply so no resistors required. That is not ground but +5V for the encoder feed.

If you want LEDs then the switches in the matrix should be DPST or DPDT. One half of the switch would be the connection for the matrix and the other half would be used to light the LEDs. There are some inexpensive 5V power supplies on Ebay that could be used as a power source for the LEDS. There are way too many to power them from the midiCPU 5V ref pad

[VFXcompositor]

Awesome, thanks a ton Jim. I'm in the process of ordering all the parts now and I think I've got everything figured out. I've got my wiring diagram pretty much finalized and I was hoping you or someone could double check my plan if you wouldn't mind. I've got the 9V battery's lower voltage replaced by the higher voltage from the 9v power supply via 2 more of the same diodes. This way (i think), the battery will kick in whenever the deck's wall power supply is not plugged in. You'd be notified of a your 9v battery dropping below 4 or so volts via the low battery LED self-contained breakout board thing i found on spark-fun The switch matrix looks like an amateur drew it lol but i feel i just make fewer mistakes by looking at it that way as it's more like the back of a panel, plus I wanted to number the corresponding buttons on the diagram and the deck to keep track as they're all over the place and not lined up any sort of pattern that resembles the wired matrix

Also, is that slide pot cool? I was pretty sure I got that right lol. Thanks!

[Jim McDougall]

You are well on your way ! However some minor revisions to your wiring diagram are required. See page 12 in the hardware manual to note which terminals can be used for analog (pots) versus matrix input (logic input). Move the matrix down to start at 1 . The pots have to attach to 8 -13 and / or 16 - 23

[VFXcompositor]

Thanks man! I made some adjustments to correct for what you had mentioned about the analogue terminals. totally forgot about that looks like I can use terminals #14 and #15 to complete the matrix. Do I have the data & select lines in the right place for the sysex later? I also added an on/off switch and moved the low batt. indicator to the proper spot in the circuit. Also added a space for some chassis LEDs (decided to go with some "dumb" leds instead of switch leds just to add some more of that appeal i'm looking for ) Let me know what you think! My midi cpu came in the mail today and i gotta say, i'm pretty stoked! it's tiny! I can fit this thing anywhere waiting for the rest of my parts in the mail and then i can put it to the test. Thanks a million for all the help and input, you guys rock!

[John]

Originally Posted by VFXcompositor

Thanks man! I made some adjustments to correct for what you had mentioned about the analogue terminals. totally forgot about that looks like I can use terminals #14 and #15 to complete the matrix. Do I have the data & select lines in the right place for the sysex later? I also added an on/off switch and moved the low batt. indicator to the proper spot in the circuit. Also added a space for some chassis LEDs (decided to go with some "dumb" leds instead of switch leds just to add some more of that appeal i'm looking for ) Let me know what you think! My midi cpu came in the mail today and i gotta say, i'm pretty stoked! it's tiny! I can fit this thing anywhere waiting for the rest of my parts in the mail and then i can put it to the test. Thanks a million for all the help and input, you guys rock!

This schematic is a work of art. Thanks for making my day.

Let us know if you need help with the configuration sysex.