Gallery, Projects and General > How do I??

Diffusing light within plastic?

(1/2) > >>

AdeV:
I've been hard at work (ahem!) making a new switch for my doorbell. I got fed up with the old cheapie mechanical switches forever failing; and I'm not about to buy an expensive one when I have a workshop full of tools, aluminium and lumps of plastic lying around. Especially not when I get to play with electronics too  :zap:

So I designed myself a touch-sensitive doorbell. A small aluminium disc with a wire going to an ATTiny single-chip computer, a few other odds & sods, and you have a touch sensor, which normally shows a white LED, and changes to blue when you touch the sensor (the bell also rings, as almost a side thing). Got all the electronics up & running and today I finally got round to making the plastic bits of the switch.

What I want to happen is a sort of "angel eye" effect around the sensor, a nice fairly consistent ring-o-light.

What I'm getting is an obvious bright light on one side, or the other, depending on which LED is lit.

See the pictures below, and it should be obvious what I'm on about... even though there's no outer box yet.

Obviously I need some kind of diffuser arrangement, but how does one create such a thing? I tried filing the tops off the LEDs (no improvement), roughed up the top plastic surface a little (no improvement); I could rough up the underside, except that's a bit tedious... I could re-arrange it so the LEDs are pointing at the sides of the plastic contraption, thus not shining directly on the surface; or I could just put them further away, so they're not directly under the ring... Any more ideas (especially if you KNOW it'll work) welcome. Note that I don't have a lot of room to play with, so if I have to put multiple LEDs in, it'll have to be SMD.

chipenter:
Have you room to put a polished refleting ring round the leds .

PK:
Assuming that the circuit will go in a box. Try using two or more leds NOT pointing up at the plastic ring. Make the inside of the box as reflective as you can.  When you are staring at it on the bench it won't seem bright enough. But in place it may well be fine..

Worth a try I reckon.....

PK

SwarfnStuff:
OR, try (if there's room) putting a ring of opaque / translucent plastic between the LED and bottom of sensor. Perhaps this will diffuse enough light to make the light more even???
John B

Mike E.:
For diffusing the light, here is a possible solution. Items needed are....... a black plastic cover from a pen or sharpie marker which would fit over the LED, a cap from a suitable plastic bottle cap cut to fit around the ringer button, and a few fibre optic strands. (possibly from one of those novelty lamps).

1.) Drill tiny holes around the plastic cap and the pen cover  for locating the fibre optic strands.
2.) Punch out the center of the plastic cap and split it to fit around the ringer button.
3.) Feed the fibre optic strands through the plastic cap, glue in place with a drop of super glue from the back side, then cut flush with the face side when dried.

The optical effect should be star like around the perimeter of the button. Here is a rough sketch, hope this helps.



 

Navigation

[0] Message Index

[#] Next page