Building chasing airport lights -- Attn: Jim Weir?

I was basically thinking of that very circuit in a small PLD (you wield a hammer long
enough and everything starts to look like a nail). You also need at least an inverter to
realize a counter. For one light on at a time, which I think is what the 'rabbit' does,
you'd need a little bit more, especially if you wanted it to recover should it hiccup. A
johnson counter (last register output inverted and fed back to the first) would make the
all the lights go on in sequence before any started going off. So, to your timer and
shift registers, add a package with a gate. For the cost and circuit board complexity,
you'd probably come out ahead using a small PLD (there are several in the $1-2 range that
would suffice) , assuming you had a way to program it. You could also use a 4 bit
counter, timer and 16 line decoder (7493, 74154 and 555). 16 Leds is probaby enough for a
Rabbit, I think most only have about 10 strobes. I'd be tempted to use white LEDs.

In any event, since he was asking, I presumed that working with logic chips was probably
beyond his capability, so I was trying to come up with solutions that would not require
any logic design. (I guess that means a CPLD would be even further out of reach of
course).

If he could live with orange lights(or perhaps green if you can still find the green neon
lamps), you could also do it with NE-2 bulbs and resistor and capacitor for each bulb. It
is a ladder network of relaxation oscillators that depends on the neon lamp's high off
resistance and low on resistance to make it flash, and the ladder network makes them flash
in sequence.

Maurice Givens wrote:

Ray, I'm shocked!! 1 timer, 2 16-bit shift registers, and 32 LED's

Maurice

Ray Andraka wrote in message ...
Jay,

There are inexpensive christmas light sequencers available. They generally use
3 circuits with every third bulb on the same circuit. I had one a few years ago
that had a switch to select chase, random or all on, and a knob to vary the
rate. Cost no more than 3 or 4 bucks and came with the lights.

That is a little bit different than the rabbit, which has only one light on at a
time, so it may not achieve the effect you are looking for. A possible low
tech solution would be a motor driving a cam that closes a series of
microswitches in sequence...easy enough to produce by someone with a little bit
of mechanical talent and not much electrical know-how. A higher tech solution
would be to use electronics consisting of a programable logic device and a set
of solid state switches to switch the current. Could also be done with a
computer with a relay card plugged into it, but would need a little bit of
programming to make it work (such relay cards are available from electronics
firms like Jameco). The computer solution would be a bit of overkill, but could
be done with off the shelf stuff.

Jay Honeck wrote:

Today a pilot-guest had the coolest idea for the side-entrance to our lobby:
"Chasing" lights recessed in the drop-ceiling tiles, leading to the main
lobby area, that look just like the "rabbit" lights that lead to the
approach end of a runway!

(Background: Over half of our guests come in the "wrong" door to our lobby,
which leads more directly to the pilot's lounge than to the reservation
desk. As a result, we've often got people milling around looking "lost" in
the pilot's lounge. These chasing lights would "lead" them to the correct
area, and be really cool looking, too.)

So, I stopped at the local Rat Shack, and found the perfect little 12 volt
blue lights, 1/2 inch in diameter. (Blue would be a bit toned-down from
white strobes!) It would be a simple matter to drill 1/2 inch holes in the
ceiling tiles, every 12 inches or so, and push them through the tiles from
above so that only the blue "dome" was sticking out through the hole. I
think 12 volt lighting would be safer in the ceiling than 120 volt Christmas
lights, as a couple of people have suggested...

Here's the problem: How to sequence them? The guys at Radio Shack had NO
advice at all -- they were all stumped. The lights should flash
sequentially pretty fast, but I think they'd look pretty stupid if they
weren't coordinated properly. I'd also want to incorporate a motion
detector on/off switch, so that they weren't running all the time.

Anyone got any ideas? Are there affordable electronic "sequencers"
available? Is this something RST Engineering could build for me, Jim?

Thanks!
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

--
--Ray Andraka, P.E.
President, the Andraka Consulting Group, Inc.
401/884-7930 Fax 401/884-7950
email
http://www.andraka.com

"They that give up essential liberty to obtain a little
temporary safety deserve neither liberty nor safety."
-Benjamin Franklin, 1759

--
--Ray Andraka, P.E.
President, the Andraka Consulting Group, Inc.
401/884-7930 Fax 401/884-7950
email
http://www.andraka.com

"They that give up essential liberty to obtain a little
temporary safety deserve neither liberty nor safety."
-Benjamin Franklin, 1759