Teensy as Keyboard - repeated keys in Linux only?

[mepler]

Hi all! Love this community.

I'm using a Teensy2 (old project revived) to send keystrokes from a TI-99A keyboard to my computer (Mac OSX10.10). It works fine when hooked up to Mac OSX, but when I plug the device into a Linux machine, I get repeated keystrokes.

Any idea what this problem is? I've had a few people contact me about the project recently who are having the same problem and I feel a sense of duty to help them solve it, but I'm stumped!

If you're wondering, YES I'm using the Bounce library (Arduino).

• Another ground connection?
• Something amiss in the code?
• Something in the Teensy2 hardware that is improved in 3?

Full Instructable with photos of breadboard setup: http://www.instructables.com/id/RaspTI-Convert-a-Vintage-Computer-TI-994A-into/

Code on Github: https://github.com/matthewepler/raspTI_keyboard/blob/master/raspTI_keyboard.ino

 

[PaulStoffregen]

Can you try running something very simple, like this?

void setup() {
}

void loop() {
  delay(5000);
  Keyboard.print('Y');
}

 

[traxxasislife]

I have also built one of these (following ops guide) but I get repeated keys (usually "1") on every os I try. I also noticed that when touching the bare keyboard to my palm stopped the repeating key issue

 

[Nominal Animal]

I haven't had any problems like that with my Teensy++ 2.0, but I don't use the Arduino environment for it, either.

when touching the bare keyboard to my palm stopped the repeating key issue

Something floating? Have you verified your resistors are connected to the Teensy ground pin with a multimeter or something? Say, measuring the resistance from the Teensy ground pin to the other end of the resistor?

Also, have you measured the keyboard matrix resistance, when a key is being pressed, but not connected to Teensy? Say, the resistance between keyboard connector pins 7 and 8 (INT7 and 1Y1), while A is being pressed? How high the resistance is when A is not being pressed?

 

[traxxasislife]

fixed it! one of the resistors was not pressed into the breadboard fully. Happily typing this on my ti99 keyboard! ;-) also working in linux and mac osx with no issues!