Lighting Microswitch Buttons

FX Buttons (aka Translucent Happ Buttons) are the brainchild of Shawnzilla and have recently become a very popular option for people looking to light up their buttons using LEDs with GroovyGameGear's LED-Wiz and PowerMAME. Basically, they are microswitch push-buttons cast from the same mold as regular Happ buttons, but using colored translucent plastics instead of the regular opaque.

They can be bought from Shawnzilla himself at FXButtons.com or from several re-sellers such as PonyBoy, DiveMaster or GremlinSolutions (UK).

Lighting Considerations

LED Viewing Angles

When buying LEDs, most people will generally go by the LEDs brightness (aka luminous intensity or MCD). Brightness is important, but when you're mounting your LEDs so they're pointing straight up through the button (as in the method described below) the most important factor in choosing an LED is it's luminous flux, which is determined by it's MCD and beam angle. An accute beam angle will cause an extreme (sometimes blinding) hot-spot in the center of the button.

Luminous Flux is a good guide to how well and LED distributes light; it takes into account how bright the LED is (its luminous intensity) and how wide of an angle light is dispursed from the LED.

Here's a simple calculator to help you easily figure out what an LEDs luminous flux is:

If you have to use an LED with a viewing angle less than 45°, it is recommended that you use the 'Kneivil' method of putting two LEDs at the sides of each button.

Choosing a Resistor

While I'm at it, here's another useful calculator for determining what size resistor each LED needs: http://led.linear1.org/1led.wiz

Mounting the LED into the Button

	1. Stick a small screwdriver into one of the actuator holes to push the spring down slightly (this might not be necessary for lighter springs).
	2. While the spring is pushed down, squeeze the actuators together and push them through the holes to remove the plunger.
	3. For 5mm LEDs, use a 3/16" drill bit. If you're not using a clamp or vise to secure the button, be sure to keep a firm grasp of it while drilling.
	4. Push the LED into the hole, it should be a pretty snug fit so you don't have to worry about it moving around.
	5. Wire it up. If you're going to be snipping the LEDs legs a little, don't forget which leg is the anode (the longer leg, positive) and the cathode (the shorter leg, usually from the flat side of the LED, negative).