Expansion Box for controller

#1

Today I finished creating an expansion module option to my controller...

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I added a TRRS jack to the side and a switch that switches between the middle pair of knobs on the controller and RR of the TRRS jack... (T=V+ R1=X R2=Y S=V-)
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I also got a 16 foot TRRS cable so I can hand the controller to someone in the audience while I perform...
The best part of this is I can cow create whatever I want in an expansion box and have 2 controllers onboard. Next up, light controller and IR Controller...

#2

Ugh, well, It works fine with a short cable, but when I switch to the 16 ft. one the X axis reads incorrectly at a constant value of 60-64
I wonder if i could put in a buffer?
Anyone got any ideas?

#3

did you check the cable with a multimeter?

my guess would be that the readings get more jittery, but not that they would fail altogether. alternatively look into short distance wireless sender/receiver solutions

#4

I did test it... it seems fine.
I get ~13R on the 16' cable and ~4R on the 1.5'
I also added 10nF caps between signal and ground close to the axoloti to see if that helped... it didnt.

So what would change the equation for just one of the signals? its not both, its not the cable, not sure what to look at...

Is this problematic?

Also, my concern with short distance transmitter solutions is two fold:
Potential for noise/interference
Theft if I hand the controller to someone else its not tethered....

#5

Congrats on the project, but regards the problem you're having, it might just be down to the increased cable length giving more potential for interference, so have you tried putting one of those ferrite chokes on it?

#6

yes that seems quite low. are you sending 5v down the long cable? that is not a very good idea i think. i have a similar situation, where i connect an external box to an arduino. my solution was to send 9v down the cable and install a 5v regulator into the external box.

so for ultimative experience you bring a router with you, and something like a raspberry pi...there are some projects that allow remote control of parameters in this way. at least for puredata etc. you could then easily connect the axoloti to the raspberry pi and send the data over via usb midi.

#7

Duh, I figured it out... its the cable... the 2 Rings are shorting out.... only way I didnt test it was ring to ring...

#8

cool i hoped and thought that this would be the case. a reading of 60 seemed so far off!!