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Brain Jr for Yamaha KP65 conversion to MIDI?

Hi All,

I'm new here, and hoping this will

I'm trying to figure out a way to convert a Yamaha KP65 kick pedal switch to midi to enable velocity. The unit is built to convert velocity through a drum module. I'm looking to use it to trigger midi through Ableton Live. In order to do this I need to convert the output of the KP65 to MIDI. It occurred to me that I might be able to do these using the Livid Brain Jr.

Now, I may be looking at this too simplistically, but my thought is that the voltage output of the sensor on the KP65 can be captured through an analog input on the Brain Jr, and converted as if it were a velocity sensitive resistor. In principle this makes sense to me until I look at the connector of the KP65 - it's using a TRS cable.

So, my question is, can anyone point me to how I would go about measuring the output of the KP65, and then understanding how to wire it to an analog header in the brain Jr? 

Once I have this down, I can create a Max4Live device to handle the MIDI Messages.



  • edited February 2016

    Hi Robin,

    So from what I read about the KP-65, it is driven by a 'Piezo' sensor, which is not natively compatible with BrainJr.
    One reason Piezo's do not work well in this manner is that their signal spikes are too short, and they can easily be missed by the A/D Converter. 
    Another is that a Piezo-electric sensor can also generate high voltages. that could possibly damage the A/D Converter
    For this reason the BrainJr does not official support Piezo based sensors.

    There is a solution for the engineering minded, where you rectify and stretch the signal, but it can be fairly complicated and can vary depending on the Piezo sensor used. 
    For this reason, we do not officially support this circuit mod either.

    Feel free to research it a bit, if you are engineering minded. There are some tutorials out there.
    Keep in mind that the BrainJr A/D Converter requires a voltage in the range 0 - 3.3V.


  • Hi Justin,

    Thanks for the response! Would I be better going down the road of replacing the piezo with a FSR?

  • The FSR will work well with BrainJr, but 

    I'm not sure how well the large rubbery drum surface would distribute the pressure over what is usually a much smaller FSR.
    You would have to experiment with that.
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