Paired lights for lit signs


You see it everywhere -- signs on buildings where a light has gone out. It is often amusing where a missing letter changes the name of the company in some silly way.

They spend fortunes on these signs, but bulbs are hard to replace. So why don't they make them with a special unit that has sockets for 2 bulbs, and switches over to the backup when the first one burns out? It's not actually that much more expensive, as you are going to pay for the 2nd bulb eventually (especially incandescent) though here you pay for it earlier.

To get fancy, you want a way for it to tell somebody that a bulb went out. A small data over power chip could constantly squirt simple low-data-rate packets down the power line, "I have a bulb that went out!" Something like the x10 protocol, which can be transmitted by a chip that costs pennies.

Could use that protocol for remote turn on/off as well if you wanted. You would wait for a few bulbs to go out before sending a worker out to replace them. That worker costs more than the spare bulb anyway.


Actually, Brad, they already do the double-bulb thing they are just ignorant of the problem until the second one dies. It's like all the people that lose RAID systems because the second disk died after running in "degraded" mode for 6 months without knowing it.

(just kidding, of course! Wel, not about the RAID thing, that does actually happen. RAID without notification is baaaaad.)

If I remember my "Illuminatus!" correctly, the missing bulbs are there intentionally. There was a name for this, something like "Fjnord"? (If I ever remember who I lent my copy of the trilogy to I'll ask for it back and re-read it.)

The 'mistake' draws the eye more than having things all OK does. Somthing to do with perceptual psychology. That was their story and there's enough of it about so that either its true or many people running illuminated signs have bought into the theory. The end result is the same either way.

better than double bulbs (which many use) is LEDs, which are starting
to be used. Lower power consumption, better MTBF.

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