16n Faderbank: build help, dev suggestions


#1

Building the 16n faderbank. Suggest mods and hacks, etc: ask for help and advice here


16n is a bank of faders [release thread] [current version:1.32]
#2

Im thinking how much work to port to a photon board - to add osc messaging. Would be very cool,


#3

So:

  • the code for reading faders is pretty straightforward and the board only really relies on one analog in, and digital outs to switch the mux. A Photon has an ADC on it already, so that’s fine.
  • If you don’t want to junk the MIDI and I2C functionality…
    • The digital MIDI out is a single pin, but you’ll need to make sure you have the library code for it.
    • I have no idea if the Photon supports USB midi or I2C. You’d probably need to port the I2C code - it’s one of the less portable and more Teensy-specific parts of the code.
  • Adding the OSC isn’t too hard, I’d imagine.
  • and then you just have to drop the Photon into the schematic - which doesn’t have the same pinout/footprint as the Teensy - and reroute the whole thing. Actually, you don’t have to reroute the whole thing - just the stuff going into the MCU…

but I am really bored of rerouting this board.

I’d note that you could probably also get the thing to talk OSC over USB-serial with much less effort. However, from the sounds of “using a photon”, you’re interested in OSC over Wifi? I’d be curious as to what the latency would be like…


#4

You could add OSC without switching to another controller:


#5

I would appreciate if somebody could redesign the pcb board so it can house 16, 100mm faders spaced 25mm apart!


#6

If any of you geniuses (genii?) would like to fiddle with this to accommodate the LED sliders (a la Batumi, Stages), have at it :slight_smile: as I think that would look awesome and we all need to relaxen und watschen der blinkenlichten amirite.


#7

In 8hp as well? :stuck_out_tongue:


#8

Yes, with motorized faders :raised_hands:


#9

having read the build guide, the i2c guide, and some more posts, i still have a question or rather would like a confirmation that i got it right about R17 and R18:
if i want to use the 16n as a leader on a bus containing only 16n and ER-301, i would need to populate R17 and R18. But, can i also not populate those resistors and instead add a powered board on the bus, like a TXb for example ?
(the use case would be to be able to use the same 16n sometimes as leader of the ER-301, and other times as a follower of the Teletype (that would be in another case ∪ on an entirely separate i2c bus from the aforementioned 301.))

If i understood things properly, the answer to this question is yes ?


#10

Thanks, I think best use case is as i would use the controller typically connected to a computer with midi then i just run max patches to copy out some data with osc commands.

A wireless photon is a bit of a red herring as ultimately you need to be wired for power anyway.

Brilliant work by the way! - just waiting on a supplier in stock of the faders now


#11

Yes. And also 20 characters


#12

I was finally able to solder this thing together and got the panel lasercutted this week, so far so good!
I’m using it exclusively to control the er301 (together with a monome grid, also i2c) via i2c out > powered busboard > 301.
Now, i’m getting a very minimal negative offset on all faders and have to adjust the offset voltage on every modulation input inside the 301 very carefully to match 0v. It’s very cumbersome!
Removing the Ansible from the i2c busboard doesn’t help. I don’t know if the source of this offset lies in the 16n or if the 301 is maybe interpreting something wrong. No offset on the jack outputs btw.
Is someone using the 16n in this configuration and can check?


#13

@elil, could you check that you used 5.6K resistors and not 56K ? An error has been reported and corrected yesterday only. As I know you’ve ordered the Mouser project, perhaps it’s the cause of the issue. Can you also put the faderbank in Debug mode and check the output of Serial Monitor ?

Even if all the errors have probably been fixed now, it’s better if people use the Octopart BOM, the official one…

By the way, how can we move all the posts about build help and suggestions from the thread https://llllllll.co/t/16n-eu-uk-group-buy-thread/18657/89 to this thread ?


#14

Yea i did notice the wrong 56k resistors and ordered the 5.6k instead. I’m using a 60cm cable from the 16n to my case, i’ve got nothing shorter at hand atm, maybe this alters the voltage?
Another issue i noticed are scratching faders when using i2c. This is especially obvious when modulating a vca after a low frequency sine, moving the fader fast up and down i get some sort of digital noise. Not happening at the 3,5 outs. Hmmmm…


#15

OK great, I’m glad you noticed it.

I used a much longer cable than yours (120cm) and everything was OK. But I guess each setup is different.

Can you try to temporarily disable the MASTER mode and put it in Debug mode ?
What does the Serial Monitor say when the device is in Debug mode ? Can you reach 0 and 127 ? (The midi values). Or can you test that with a computer and Midi Monitor ?
The pull-up resistors are soldered on ?
Try to adjust the MINFADER VALUE in config.h maybe.

The CV outputs are directly sending the voltage it’s not processed by the Teensy, that’s why their output is more “fluid”


#16

Alright, this solved it! Had to push the value up to 210.
Thanks for your help Matt!

Yea. I guess if there would be a possibility to add a bit of slew on the teensy i2c output there would already be a option implemented.


#17

Same thing here, I get the best results with the MINFADER value at 200-210.


#18

Try adding a slew unit to the assigned controls in the 301. I was having a similar problem w/ a controller and the FH-1 and that was my solve.


#20

A couple thoughts on pcb/panel spacers…

Depending on your fader caps and panel thickness, you might want to change/adjust the panel height.

For example - with the black fader caps i have, the sit very high on 15mm tall faders. By using a 13mm spacer instead of 10mm you can raise the panel up a bit to meet the faders. Also - it looks like you could drop the back spacer down a couple mm (3mm instead of 5 or 6).

i’ve got a few of these on order to test out different configurations:
https://www.mouser.com/ProductDetail/855-R25-1001302
https://www.mouser.com/ProductDetail/855-R25-3000302


#21

Dev idea or suggestion because I’m sure someone already thought about that: what about using the 16n as a MIDI to i2c converter, (in addition to the 16 faders) ? The connectivity/io (usb, midi, I2c) already exists, so…