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geekhack Projects => Making Stuff Together! => Topic started by: berserkfan on Sat, 30 August 2014, 05:30:00

Title: can we put LEDs instead of keyboard diodes?
Post by: berserkfan on Sat, 30 August 2014, 05:30:00

I'm writing this because I have been inspired by Hak Foo.

I have an Access-IS plate mounted keyboard with diodes where LEDs are normally soldered. Desoldering this keyboard has been hell and I really don't feel like soldering back the diodes.

Now that has made me wonder. If I am satisfied with 2KRO, instead of soldering back diodes can I solder light emitting diodes instead?

I think the main technical problem will be controlling the brightness, right? Without resistors there will be the danger that the diodes burn out. And I won't be able to turn the lights down without the appropriate controls on the keyboard?

Just musing on theoretical matters. I have an entire weekend to mod, and will be busy putting my new dremel to work.

Title: Re: can we put LEDs instead of keyboard diodes?
Post by: dorkvader on Sat, 30 August 2014, 10:30:35

There usually isn't enough power in the KB scan to power LEDs so you'll see them. You'll also likely need resistors to properly match resistance.

Also, if you installed LEDs backwards, you might get light from them, but you'll lose NKRO. If you install them "properly" you'd have NKRO, but the LEDs wouldn't light up.

The diodes are there to prevent current from flowing. If there's current in them, then something has gone wrong.

I don't think there is a danger of burning out the LEDs, There is a very real danger of burning out the controller chip immediately once power is applied.

I could be wrong though, I haven't had any EE classes.