Sixteen-N Faderbank

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#1

@tehn and i have been working on a faderbank!

same dimensions as the 128

high quality alps pots. smoooooooove.

prototype laser-cut 3mm ply front panel

assembled with some scavenged plastic caps. i’ve yet to find a domestic source for multicolored caps. i’d like to find blue, orange & yellow in addition to the white and red.

the teensy is flush with the panel and inset from the edge, so i had to cut a notch for my slightly beefy micro usb cable.

also, i discovered that while the teensy is flush, the onboard pushbutton protrudes slightly. i had to carve out a notch in the back of the ply frontpanel to allow clearance.

i was getting a little flex in the middle of the unit, so i rolled up some gaffers tape as supportive spacers.

haven’t installed all the mounting screws yet, planning to disassemble so i can paint and finish the front panel.

so yea, this is still a work in progress - there are some things to work out with the panel/hardware/support - but we were excited to share this with the community and get the resources in your hands. can’t wait to see where this goes and grows :slight_smile:

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eagle files: download (schematic and board). panel layouts included as layers in the eagle file.

pcb: 3 boards for $196 via oshpark

teensy: available as add-ons to your oshpark order

panel pdf/dxf: https://drive.google.com/folderview?id=0B_o0FqI2h7Z4VExOa21FcFNhcDA&usp=sharing

faders: Alps RS6011SP6003

teensy headers:

• single row http://www.digikey.com/product-detail/en/sullins-connector-solutions/PREC040SAAN-RC/S1012EC-40-ND/2774814

• double-row smt http://www.digikey.com/product-detail/en/molex-llc/0015910160/WM17462-ND/614778

hardware: please note that this could use some refinement - i’m just sharing what i did

• fader/panel mount - thirty two M2 screws, 6mm long + washers

• corner support - the panel was cut with four M2 holes at the corners, but i was unable to source metal spacers/standoffs in that size so i had to orer M2.5 screws/standoffs. with a bit of finesse i was able to fit these larger screws into the corner holes without splitting the ply, but if you’re making a metal panel the holes will need to be adjusted. the standoffs are 14mm in length.

• pcb/back-panel mount - there are four M2 holes in the corners of the pcb, intended to mount to the back-panel. i didn’t account for the small gap between the pcb and back-panel when ordering hardware, so that is currently unmounted. i will update this section once that is resolved.

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code

const int ports[] = {A0,A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16};
int v[2][16];
int last;

void setup() {
}

void loop() {
  for(int i=0;i<16;i++) {
    last = v[0][i];
    v[0][i] = (analogRead(ports[i]) / 4 + v[1][i]) / 2;
    if(v[0][i] != last)
      usbMIDI.sendControlChange(i, v[0][i] / 2, 1);
      
    v[1][i] = v[0][i];
  }
  delay(4);
}
31 Likes

Faderbank Run: See top post for status
Faderbank Run: See top post for status
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Faderbank Run: See top post for status
#2

ahhhhhhhhhhhhhhhhhhhhhhhhh! (liberal h usage not just to get to 20 char. this is that exciting)

1 Like

#3

Fantastic! I would love one of these.

0 Likes

#4

Oh dear. I need this for so many reasons.

0 Likes

#5

Wooooow! That is exactly what I was looking for here:

Looks perfect!!!

0 Likes

#6

This looks really nice.

0 Likes

#7

I would very likely pick one up.

1 Like

#8

thank you so much for this!

0 Likes

#9

Very cool!

What about outputs, inputs, functionality…?
Are there specific plans, or are people supposed to develop their own firmware and do the necessary hardware alterations to suit it?

1 Like

#10

It’s USB Midi - that code snippet above is all it takes to turn the Teensy on the board into a class-compliant MIDI faderbank spitting out CCs 0-15 on Channel 1.

Anything more complex would be an exercise for the reader.

4 Likes

Faderbank Run: See top post for status
#11

oh, i see.
thanks for pointing that out.
so, laptop and MIDI centric at this point.

0 Likes

#12

Brilliant simplicity. I love it.

1 Like

#13

Nice project! Well done.

0 Likes

#14

I wonder what it would take to give it a hardware midi output?

2 Likes

#15

Yeah, some form of non-USB MIDI is always nice. Perhaps one of those 1/8" jacks that are becoming popular of late, if 5-pin is too bulky?

0 Likes

#16

or CV for that matter…

2 Likes

#17

Hardware MIDI = not so hard. Output requires two resistors and a DIN jack and a spare output pin on the Teensy. Of course, if you want it to do more than just spit out those CCs on channel one, you begin to require UI…

1 Like

#18

yeah. the 3.5mm jack would fit much better with this slim design

0 Likes

#19

CV: much more involved. For starters, you need D-A conversion. There’s only one proper DAC output on the teensy, and you’re clearly going to want more than that. So you need a DAC chip, and free SPI pins for the teensy to ping the DAC chip with, and impedence resistors on all the outs, and god knows what else, and of course, because this whole circuit is taking USB power, you’re only really going to get a maximum of 0-5V from your DAC. So if you want wider than 0-5V, you need external power, and then you need to start doing things to filter and step it down and… wow, this just turned into a much, much bigger pile of work.

3 Likes

#20

hey everyone!

here are the eagle files (schematic and board).

adding midi out would be completely trivial, someone feel free!

also to be very clear-- you can order these boards yourself via that oshpark link in the first post. it’s $196 for three boards, so appropriate for group buys (between trusted parties).

16n-eagle.zip (12.9 KB)

the “plate” layouts are included as layers in the eagle file.

enjoy!

4 Likes