keypad progress

John Larkin · 2017-09-02T17:39:45+00:00

We're doing a new box that will have a front panel with molded silicone keypads with backlit pushbuttons. We got prototype silicone thingies from Melrose. There are a zillion theories about the best finger pattern on the PCB, so we just did a simple, maximum-target-area array of parallel traces. which makes beautiful contacts no matter how I mash the buttons... The buttons are backlit from down-firing surface-mount LEDs on the farside of our PCB. It looks pretty good in real life, decent light uniformity thanks to the milky silicone, but there is a little light bleed between nearby buttons, and Melrose may be able to improve that with some moulded channels or something. Of course I had to play with the LED currents to balance the brightnesses of the various colors, about 3:1 between green and blue. I can clock the LED drive shift registers from one pulse generator and feed the SPI serial data in from another one, and get all sorts of fun randomish blinking patterns. Gives my office a festive air. -- John Larkin Highland Technology, Inc lunatic fringe electronics

Sep 02, 2017 25 Replies

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bitrex 8 years ago

Remember the first rule of LED-having user interface design: thou shalt not have blue and green without something in between.

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Joerg 8 years ago

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:-)

Regards, Joerg http://www.analogconsultants.com/

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bitrex 8 years ago

Ugh, looks like a nail salon.

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Clifford Heath 8 years ago

Someone didn't get the memo: "Blue with green, should never be seen".

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Joerg 8 years ago

Depends on who is in it :-)

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Regards, Joerg http://www.analogconsultants.com/

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krw 8 years ago

The burgundy looks better.

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