Photo sensitive switch problem

[WKPrather]

  Hello, I am a non-engineer type trying to figure out how to alert an operator that an indicator light is flashing at another location.  Basic parameters are: 

1. Outside daylight operation.
2. Can’t be hard wired.  Peel and stick is the desired connection method.
3. Distance to new location is only 18 inches.
4. Battery powered.
5. Light activated (source is approximately 3/8” in diameter). 

Ideally the new light (indicator) would begin flashing if the source light starts flashing and stops when the source stops. 

[johnsold]

Several other questions:

1.  What kinds of materials occupy the 18 inches between the  original indicator and the new one?  Are they opaque to visible light?  Are they electrically conductive?

2.  What is the duty cycle of the light?  How often is it on?

3.  Can the original light be obscured by the added device or must it still be readily visible to someone in the area?

4.  Are both parts (the transmitter and the receiver) required to be battery powered?  How long do the batteries need to last?

5.  What kind of regulatory environment is active?

6.  What level of reliability is required?  How many false positives and how many false negatives can be tolerated per day (or other time unit)?  What are the consequences of missing an alert or alerting falsely?  Who is liable for erroneous indications?

7.  How much space is available at the original indicator and where the new indicator goes?

Lynn 

[WKPrather]

 

Hello, Thanks for responding.  What I would like to develop is a way to alert a motorcycle rider that a turn signal light is still flashing. I constantly see riders (including myself) forget to cancel the turn signal. On motorcycles they do not self cancel. Occasionally it can be misleading enough to pose a danger. I don't think many folks will crack into the bikes electrical system and that is why I would like to see if its possible to do it another way. What I was thinking was a battery powered cluster of 2 or 3 LED's. Ideally the switch would be a phototransistor (if I understand that correctly) that could be a "peel and stick" item that could be put directly over the 3/8" (or so) green light on the instrument panel. Approximately 18" of wire to the LED's would allow the operator to attach it (peel and stick again) higher up on the bike. Perhaps part way up the windscreen. During daylight operation the riders attention is pretty focused on the road and you don't see the flashing light on the instrument panel.

The other way would be a switch designed to "stick" over the existing turn signal switch. They are on-push to cancel-on type of switches.  This would be the preferred choice.  I would run wire to each rear view mirror and stick a LED on the inside edge of the mirror. Riders are constantly checking the mirrors (at least frequently) and I believe would notice that.

Anyway, your thoughts and/or direction would be appreciated.  Thanks, Bill Prather

[johnsold]

Bill,

Why not run a piece (or two) of plastic fiber optic cable from the instrument panel to the windshield or mirror?  No cutting into wiring, no batteries to replace, no fancy circuits, weather resistant, cheap.

I thought of this for cars many years ago when the bulb-burn-out circuits began to fail one one of my cars.  If the manufacturers simply ran fiber optic cables from the lights to the dashboard, the driver would have a direct indication that the bulbs were working without any extra circuits and no need for lamps in the dashboard which are hard to replace when they fail.

Lynn 

Message Edited by johnsold on 11-19-2008 03:29 PM

[WKPrather]

Hi Lynn,  That sounds too easy.  Do you think enough light would be emitted at the other end to be visible in sunlight?  I need to get a small quantity of fiber optic cable and play with it.  Ideally I would be able to attach a ring around one end, peel and stick it right over the indicator light on the instrument panel and with zip ties and more peel and stick or velcro material, get it to where I want it.  So..... I can look it up, but is it easy to find plastic fiber optic cable of various diameters?  Thanks a lot for your help,  Bill

[johnsold]

Bill,

You may be able to play around with lenses if necessary to collect or direct more light. 

I have not looked recently, but hobby shops sometimes have some.

Let us know  

[WKPrather]

Thanks,  I'll work on it and let you know what I find.  Bill

[WKPrather]

Just a quick follow up.  You were right about the plastic fiber optic cable.  This will work as far as transfering the light to where I want it.  I will put it together on my motorcycle this winter and see how it works when the weather improves.  Thanks for your help.  Bill

[johnsold]

Bill,

If all your friends want one and you get rich, keep me in mind.  Glad it works for you.

Lynn