Super mini momentary push button switch w/ LED

homosapien

I'm working on a project that requires an interactive 'map' that has embedded push buttons that illuminate when the button is pushed (ie shows status of button-controlled device). The 'map' will be about 4 inches x 6 inches and have about 14 of these buttons randomly (well, not random, but not in a grid of any sort, just placed where the device is located on the 'map') scattered about. The buttons need to be small, I was hoping to find something about the size of a 5mm LED. Needless to say, I cannot find any commercially available SPST momentary buttons with LED illumination that are as small as I need (and the ones I am finding are kind of expensive, ($5 -$10 each).

So, as usual, I am thinking about making my own (why buy when you can spend much more time rolling your own? haha). I have plenty of 5mm LEDs on hand as well as many tactile SPST momentary PCB mount buttons. Could combine for a switch cost of only ~$0.35 excluding time in labor. I am planning on drilling some plastic sheet stock for the 5mm LEDs and then mounting the PCB switches on perf board to be held right behind the plastic LED holder. The user would press the actual LED, which would press the PCB switch and I'm off to the races....

Is this a crazy idea? Anyone know of a cheap, easy solution that is better?

As an alternative I was thinking about having each LED surrounded by a separate loop of wire and using a capacitive sensing algorithm of some sort. The user would simply need to touch the LED and the switch would be activated. The problem with this is that I'm not sure how reliable it would be (100% error free operation is always nice) and I could spend even more time playing around with this approach and never getting something that works... (I am using a Propeller as the uC on this project).


Thanks for any ideas.
Nate

tonyp12

$1-2
http://www.mouser.com/Electromechanical/Switches/Pushbutton-Switches/_/N-5g30Zscv7?P=1z0z2nj&Ns=Pricing%7c0

If you want a small hole in pcb and pcb touch sens around the hole, Reverse Gullwing led's
http://www.mouser.com/Optoelectronics/LED-Lighting/LED-Emitters/Standard-LEDs-SMD/_/N-b1bb1Zscv7?Keyword=Reverse+Gullwing&Ns=Pricing|0

Just reverse, a round hole could work but milled holes preferred. should have better viewing angle as lighted side is more flush with pcb
http://www.mouser.com/Optoelectronics/LED-Lighting/LED-Emitters/Standard-LEDs-SMD/_/N-b1bb1Zscv7?Keyword=Reverse&Ns=Pricing%7c0&FS=True

kwinn

There was a thread on using leds as sensors where a finger placed over the led could be detected. That was done without illuminating the led, but I wonder if it would be possible to do both by rapidly switching between driving the led to light it and reading the voltage when it is off. That would certainly simplify this project.

kwinn

If my previous suggestion is not practical you might try a led with a phototransistor mounted next to it to measure the light reflected by the finger covering the led.