Re: Dead simple Arduino MIDI controller for PTT button.

Christian Veith

I think there are not many left, as the encoders require two pins each.

But the library i'm using can handle external inputs via i2c bus. It would be possible to attach a cheap 8 pin i2c input ic and also use matrix input selection.

Would be a little bit more wiring but drastically reducing the number of pins used.

But matrix is only possible for switches with a limited number of state changes, as rows and columns are read after each other.

I wouldn't use it for encoders ;)

Best regards


Am 14.05.2020 um 22:21 schrieb Andrea Dalbagno:



By the way, how many free pins did you left on Micro? I mean, is there room for more pushbuttons/encoders or do you think you'll need another Arduino for your planned expansions?

Just ordered some components on Amazon :-)


Il gio 14 mag 2020, 22:02 Christian Veith <dl5cv@...> ha scritto:

Sorry forgot to attach the pictures :(

Am 14.05.2020 um 21:34 schrieb Christian Veith:

Hi Andrea,

yes of course, but i wouldn't call it a PCB ;)

Just a strip pcb meant for prototyping.

The vertically arranged resistors are for limiting the LED current.

The horizontally arranged resistors are pullup resistors for the VFO A, B and PTT Buttons.

There are 3 KY-040 encoders completely with their own pcb and Button and Encoder Output pins.

I've tried to attach them to pins having interrupts in the arduino to have a better switching sense.

I really would like to extend it to have another bunch of controls on it.

I think a RX=TX (On Off), RX -> TX (Sync) would be cool. I also would like to add a Mode selector.

And the top of my list would be a little display to show the selected value, when selecting something ;)

But it had to be quickly available and it's working flawlessly since nearly a year.

Best regards


Am 14.05.2020 um 17:10 schrieb Andrea Dalbagno:
Hallo Chris,
May I ask you to show us, when you have spare time, a schematic of your arduino micro knob or at least a photo of the back of PCBs? 
Thank you very much :-)


Andrea SWL I-1360TN

Il gio 14 mag 2020, 16:13 billcoombes <bill@...> ha scritto:
Thanks Chris and I really appreciate your help.
Bill - G4ERV

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