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Teensy with LEDs

Teensy with LEDs

From:
Michael Reilly
Date:
2015-06-19 @ 09:49
Has anyone tried adding a LED strip like https://www.pololu.com/product/2547
to an atreus with a teensy controller? It'd be really neat to be able to
program the keyboard to control LEDs to shine through an acrylic case. My
concerns are whether the teensy can output enough voltage for the LEDs,
whether it has enough processing power to handle the keyboard inputs and
the LEDs at the same time, and whether the atreus even has enough space to
fit any LEDs inside. I haven't built an atreus yet, but I think it'd be fun
to play with. My main inspiration is the winkeyless keyboards seen here
http://blog.winkeyless.kr/186 using the same LEDs. Any thoughts?

Re: [atreus] Teensy with LEDs

From:
Joe Fiorini
Date:
2015-06-19 @ 11:17
While not exactly the same thing, the cherry switches actually have a
spot for individual LEDs, which would resolve your space concern. If you
look at a switch you'll see two little holes next two each other with a
round indentation. Eventually I'm hoping to use that to make myself a
backlit keyboard.

--
Joe Fiorini
 
 
On Fri, Jun 19, 2015, at 05:49 AM, Michael Reilly wrote:
> Has anyone tried adding a LED strip like 
https://www.pololu.com/product/2547 to an atreus with a teensy controller?
It'd be really neat to be able to program the keyboard to control LEDs to 
shine through an acrylic case. My concerns are whether the teensy can 
output enough voltage for the LEDs, whether it has enough processing power
to handle the keyboard inputs and the LEDs at the same time, and whether 
the atreus even has enough space to fit any LEDs inside. I haven't built 
an atreus yet, but I think it'd be fun to play with. My main inspiration 
is the winkeyless keyboards seen here http://blog.winkeyless.kr/186 using 
the same LEDs. Any thoughts?
 

Re: [atreus] Teensy with LEDs

From:
Phil Hagelberg
Date:
2015-06-19 @ 14:50
Michael Reilly <mreilly95@gmail.com> writes:

> My concerns are whether the teensy can output enough voltage for the
> LEDs, whether it has enough processing power to handle the keyboard
> inputs and the LEDs at the same time, and whether the atreus even has
> enough space to fit any LEDs inside.

The USB spec dictates that you should have at least 500ma available
total, and I believe the controller board itself shouldn't take more
than 10% of it. So you should be able to drive some LEDs, but probably
not the whole strip, and even then probably not at full brightness. But
definitely enough to make it look cool. The processing power shouldn't
be a problem; the thing runs at 8MHz, which is hugely overkill for
simply scanning the matrix. If you have incredibly complex lighting
logic you could see your scan rate drop, but this seems unlikely to
reach above the threshold of perception.

Finding space in the case might be tricky. If you can do that, the main
difficulty would be that you need an open PWM-capable pin to drive the
LEDs. All the PWM pins are wired into rows and columns on the PCB, so
you would have to leave one of them unconnected to the PCB and wire it
into your LEDs, then remap the affected column to another pin that isn't
hooked into the PCB. You can see an example of that here where I routed
around a damaged pin:

  https://github.com/technomancy/tmk_keyboard/tree/luxbock

Hope that helps. Happy hacking.

-Phil