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Dan
08-27-2013, 01:51 PM
I have created a USB-MIDI footswitch who is working good.
I have a friend who told me that when he used it in outdoor, and put the pedal in the outside he has got tons of midi messages sent.

Then he puts the pedal on a clothing, and the digital inputs stopped to send undesired messages

Do you have an idea why?

What can we do to avoid such problems on Teensy 2 boards

PaulStoffregen
08-27-2013, 03:10 PM
Maybe it's picking up noise? Is the pedal in a metal enclosure? Is the metal connected to ground, or the USB cable's shield?

You posted zero info about the circuity. Is the pedal switch just a normally open switch? I'd guess it's connected between ground and a pin. Is the pin configured with INPUT_PULLUP? Is there a physical pullup resistor?

You also didn't post the code. Are you reading the pin with the Bounce library (as is shown in the example in File > Examples > Teensy > USB_MIDI), or some other way?

All of these details make a difference. There may be other things wrong too. Without seeing what you're actually doing, nobody could know.

Dan
08-27-2013, 04:09 PM
Maybe it's picking up noise? Yes !

Is the pedal in a metal enclosure? Yes. Is it important? Some of my modules are not enclosed, and some are with plastic case

Is the metal connected to ground? Not sure. Is it important?

or the USB cable's shield? How to do it? one end of the usb cable is in the teensy mini usb port. Other end is on the computer

Is the pedal switch just a normally open switch? Yes

I'd guess it's connected between ground and a pin. Yes

Is the pin configured with INPUT_PULLUP? YES

Is there a physical pullup resistor? NO

Are you reading the pin with the Bounce library (as is shown in the example in File > Examples > Teensy > USB_MIDI), or some other way?
I am waiting 50 milliseconds of same digital value before sending an MIDI event.

Finally, here is the picture of the thing.
It's a synth pedal hack the original db15 connector has bin replaced by USB one.


Before : The pin with a red circle is the GND of teensy. mmm... I can see the most left cable is protected with something more. Maybe connected to the metal. We did not used this point in the new module.
869

After:
868

Dan
09-07-2013, 10:23 PM
I dont want to take too much of your precisous time, so if someone can just point to me some useful links so I can understand better how to protect the teensy from the outside noise, I will be happy...