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Brain Jr Buttons Overriding Each Other

edited August 2014 in Hardware

I am putting together a simple Brain Jr project and I am having trouble with the buttons overriding each other.

  • I would like to use 12 momentary buttons to activate 12 tracks in Ableton Live.
  • The buttons have built in LEDs that I have working using local control.
  •  I have soldered my connections to a LED matrix board and I'm using that to go to terminal strips.
  • "brainjr_213_BL.hex" firmware has been installed onto the Brain Jr board.

When button one is triggered and released I get the proper MIDI signal. Same with button two. When I trigger and hold either button and trigger the other button it "releases" the held button and does not trigger itself.

Please let me know if you need any other information, screen grabs, photos. Thanks for your help.



  • You'll need to connect a diode between the (-) side of each button and the BR connection on the shield. This will fix your issue. Its being documented now, very sorry for the confusion!

  • Thanks for the response.

    Should the diode be in a particulate direction? Is there a recommended part?

  • edited August 2014

    This is working.

    I found that cathode needs to be towards the board and anode towards the button on the (-) side of the button loop. Both rectifier and silicon diodes work.

    Thanks for your help.

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