Close

Oops! Lol

A project log for Mini rpi2 laptop

Small form factor laptop in the style of old HPC's like the Jornada.

pdrift86pdrift86 01/21/2016 at 01:2511 Comments

Well In all my excitement building this thing, I overlooked how many i/o I needed vs how many I have available on the teensy. I need 23 for the keyboard, 4 for the joystick, and 4 for the 2 pushbuttons. Unless I got it wrong on the 2 pushbuttons. Maybe I don't need 4. I'm not sure if i can get away with 3 if they share a pin. Either way, that's 31 pins of i/o that i need and the teensy 2.0 only has 25. I also have a teensy lc on hand but that still only has 27. I just ordered a teensy 2.0++ on amazon which should be here by Friday.

I'm not really sure on the wiring part. I have an idea and I'm looking in to it. The part I'm confused about is which pins to wire my components up to on the teensy. I think the analog joystick has to be wired up to analog pins, it has 4 pins and from what i found online they are ground, y axis, vcc, and x axis.

As far as the keyboard goes, i think any io pins should work as well as the pushbuttons.

I could use some help with the wiring up of the teensy thing lol.

Discussions

Craig Hissett wrote 01/25/2016 at 17:37 point

I agree with what the other chaps have said - I was going to suggest using a resistor ladder, then you can have multiple buttons returning different values to one pin :)

  Are you sure? yes | no

pdrift86 wrote 01/25/2016 at 23:25 point

I like this idea. I already have the teensy 2.0++ with more pins but I will try that out in a future project. Right now I'm having trouble programming the teensy. 

  Are you sure? yes | no

Craig Hissett wrote 01/25/2016 at 23:51 point

Good man. It's great; I used it on an Arduino pro micro in a footswitch for a PC (for controlling start/stop/recording in a recording studio).

What issues are you finding with the teensy buddy?

  Are you sure? yes | no

pdrift86 wrote 01/26/2016 at 00:01 point

For some reason I couldn't reply to your last comment so I'll reply here. Well i think i flashed a bad hex file with teensy loader. Now I can't seem to reprogram it. I tried flashing the arduino blink sketch but it won't work.

  Are you sure? yes | no

pdrift86 wrote 01/26/2016 at 00:01 point

For some reason I couldn't reply to your last comment so I'll reply here. Well i think i flashed a bad hex file with teensy loader. Now I can't seem to reprogram it. I tried flashing the arduino blink sketch but it won't work.

  Are you sure? yes | no

Craig Hissett wrote 01/26/2016 at 11:27 point

Hmmm... Having never played with the Teensy I'm unsure how to advise. I will certanily see if i can find some info on how to save it if i can!

  Are you sure? yes | no

polishplaya wrote 01/22/2016 at 15:04 point

forgiveness

  Are you sure? yes | no

Antonio Regueira wrote 01/21/2016 at 08:31 point

I remember one year ago i had the same problem, i found that i could add buttons to 1 wire, you only have to add a different value resistor to each button (From 5V), if you read the voltage you know what button is high. i tried it with 10 button and it works perfectly with an Arduino, only connecting 2 wires (the other wire is ground with other resistor).

I think that teensy has analog read too and you can use it to the keyboard and pushbuttons, but the joystick needs an independent wire.

  Are you sure? yes | no

pdrift86 wrote 01/21/2016 at 17:43 point

Wow, I did not know you could do that! I will look into it. Thanks!

  Are you sure? yes | no

RasmusB wrote 01/21/2016 at 07:49 point

I think you can get away with three pins for the two pushbuttons - 2 I/O pins on the Teensy, and one GND connection. Connect one pin from each button to an I/O pin, and the other button pin to a shared GND wire.

Then, just enable the internal pull-ups on the IO pins. That way the pin will be high when the button is not pushed, and low shen pushed.

https://forum.pjrc.com/threads/7531-Internal-pull-up-and-pull-down-resistors-on-teensy-3 (same for Teensy 2)

  Are you sure? yes | no

pdrift86 wrote 01/21/2016 at 17:44 point

Thanks, I will look into it.

  Are you sure? yes | no