Lighthouse project

[Franktrem]

I am a volunteer at our local lighthouse and have been asked to make a
wooden sign in the shape of the lighthouse so that they can measure the
height of children who can climb the lighthouse stairs. The minimum
height is 42" tall.

I don't have a problem with the woodworking aspect but thought it would
be a neat idea if I could incorporate some inexpensive electronics that
would sense a height greater than 42" and light a small bulb at the top
of the lighthouse.

I was thinking of a low voltage circuit that could be powered by a
battery. My talent in electronics is rudimentary.

Could anyone suggest how this might be done?

Thanks

 

[Dan Hollands]

I am a volunteer at our local lighthouse and have been asked to make a
wooden sign in the shape of the lighthouse so that they can measure the
height of children who can climb the lighthouse stairs. The minimum
height is 42" tall.

I don't have a problem with the woodworking aspect but thought it would
be a neat idea if I could incorporate some inexpensive electronics that
would sense a height greater than 42" and light a small bulb at the top
of the lighthouse.

I was thinking of a low voltage circuit that could be powered by a
battery. My talent in electronics is rudimentary.

Could anyone suggest how this might be done?

Thanks

You could use the garage door sensor that keep the door from closing is
something is blocking. The send a beam from transmitter to receiver and
generate a signal when the beam is broken.


--
Dan Hollands
1120 S Creek Dr
Webster NY 14580
585-872-2606
[email protected]
www.QuickScoreRace.com

 

[Spehro Pefhany]

I am a volunteer at our local lighthouse and have been asked to make a
wooden sign in the shape of the lighthouse so that they can measure the
height of children who can climb the lighthouse stairs. The minimum
height is 42" tall.

I don't have a problem with the woodworking aspect but thought it would
be a neat idea if I could incorporate some inexpensive electronics that
would sense a height greater than 42" and light a small bulb at the top
of the lighthouse.

I was thinking of a low voltage circuit that could be powered by a
battery. My talent in electronics is rudimentary.

Could anyone suggest how this might be done?

Thanks

Perhaps a copper plate on the floor and another plate 42" above the
floor (on the wall). The easiest way to get a complete circuit would
be with an old oil-ignition transformer, but you might want to use
something low voltage that detects capacitance between the two plates.


Best regards,
Spehro Pefhany

 

[Rich Webb]

I am a volunteer at our local lighthouse and have been asked to make a
wooden sign in the shape of the lighthouse so that they can measure the
height of children who can climb the lighthouse stairs. The minimum
height is 42" tall.

I don't have a problem with the woodworking aspect but thought it would
be a neat idea if I could incorporate some inexpensive electronics that
would sense a height greater than 42" and light a small bulb at the top
of the lighthouse.

Just to be a contrarian...

A wooden sign with a horizontal "Children must be THIS tall to enter"
marker is relatively fool-proof.

Additional complexity should take into consideration the liability
consequences if Little Johnny gets hurt, Little Johnny is less than 42"
tall, and LJ's parents swear that "The light went on saying it was safe
for him to climb the stairs."

Not recommending that you not do this but providing an affirmative
indicator could mean that you (or the lighthouse foundation or ...)
accepts some responsibility, and the device should be designed with that
in mind. A "must be THIS tall" sign would seem to leave the
responsibility and liability with the accompanying parent/guardian.

 

[spinning]

Rich makes a great point about liability. However, what if the light
simply lit and it's purpose was only implied, without any statements or
indications about the significance of the light? Also keep in mind
that even if the device worked perfectly, a short kid can still wave
his hand and the light will go on. It's a cool idea, and if you do
decide to build it, the optical sensor is the obvious solution. If
possible, you could add something to entertain the kids not tall enough
to go in.

Keep in mind that if a parent brings two kids, and one of them isn't
tall enough, they'll probably wait outside and let the other kid run
up. So you might also want a sign to tell whether or not parents must
accompany kids inside the lighthouse.

Back to the sensor. Do you have access to a power outlet? If not,
you'll need a solar cell (probably 5-6 volts), an optional backup power
supply (battery and battery charger). 2 diodes to select the power
source, an LED, a opto-transistor, another LED. Actually, it's not as
simple as it sounds.

MP

 

[Mac]

I am a volunteer at our local lighthouse and have been asked to make a
wooden sign in the shape of the lighthouse so that they can measure the
height of children who can climb the lighthouse stairs. The minimum
height is 42" tall.

I don't have a problem with the woodworking aspect but thought it would
be a neat idea if I could incorporate some inexpensive electronics that
would sense a height greater than 42" and light a small bulb at the top
of the lighthouse.

I was thinking of a low voltage circuit that could be powered by a
battery. My talent in electronics is rudimentary.

Could anyone suggest how this might be done?

Thanks

I think they have paired devices at radio shack which can send out some
signal when the optical path between them is interrupted. You may want to
go check out what they have prior to doing any actual electronics design.

If you are not in the US, there must be something like Radio Shack where
you live.

--Mac

 

[Ross Herbert]

I am a volunteer at our local lighthouse and have been asked to make a
wooden sign in the shape of the lighthouse so that they can measure the
height of children who can climb the lighthouse stairs. The minimum
height is 42" tall.

I don't have a problem with the woodworking aspect but thought it would
be a neat idea if I could incorporate some inexpensive electronics that
would sense a height greater than 42" and light a small bulb at the top
of the lighthouse.

I was thinking of a low voltage circuit that could be powered by a
battery. My talent in electronics is rudimentary.

Could anyone suggest how this might be done?

Thanks

Why not simply have the lighthouse model exactly 42" high and make
sure kids walk in single file between the model and an entry control
person. It isn't difficult to tell if a kid is shorter than the top of
the model by visual means. That way there is no need to warn anybody
or create the impression that liability is implied if kids don't
measure up. You simply stop the short kids and steer them to a holding
area where they can be otherwise occupied. It also ensures that nobody
can pretend they are higher than they actually are by some nefarious
method. Electronic methods for such tasks are not foolproof.

 

[spinning]

I have an idea. Just use a button to turn on the lamp. Put the button
up high so that only people over 42" tall can reach it. This makes the
circuit extremely simple. Just put a momentary switch in series with
the power supply and the lamp. If the lamp is an LED, you'll also need
a suitable resistor in series with the LED.

MP

 

[Fred Bloggs]

Perhaps a copper plate on the floor and another plate 42" above the
floor (on the wall). The easiest way to get a complete circuit would
be with an old oil-ignition transformer, but you might want to use
something low voltage that detects capacitance between the two plates.

Complete circuit for what? To jolt the kid with 10,000 Volts?

 

[Fred Bloggs]

I think they have paired devices at radio shack which can send out some
signal when the optical path between them is interrupted. You may want to
go check out what they have prior to doing any actual electronics design.

If you are not in the US, there must be something like Radio Shack where
you live.

Most likely talking about New York Harbor vicinity:
http://www.lighthousemuseum.org/harbor.htm
These are all oldies- model should be made of metal, clear plastic, and
plaster simulated masonry.

 

[Ken Smith]

I was thinking of a low voltage circuit that could be powered by a
battery. My talent in electronics is rudimentary.

Could anyone suggest how this might be done?

Ignoring all the practial issues for a second:

Make the sign a right angle when looked at from above. Both faces are
made to look like the lighthouse.

Assume the sign is place so that the measuring side of it faces south and
the person is directed to stand with his back against it to be measured.

When the person is not there, the sun light falls on an opening in the
model of the lighthouse. This opening could be made to look like a
window.

In the "display side" the model has openings where the the glass of the
light would be.

Between the opening on the "measuring side" and the "display side" there
is a passage lined with aluminum foil. Just behind each opening there is
a mirror.

Normally, the light from the bright sky to the south shines in one opening
and is directed up to the other. When a person blocks this light, I would
be obvious so someone on the east or west facing "display side"


No electronics needed.

 

[Tim Wescott]

Complete circuit for what? To jolt the kid with 10,000 Volts?

Sure. Just put a notice on the sign that says "if your child stands
_here_ then starts twitching and drooling he's tall enough!"

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Posting from Google? See http://cfaj.freeshell.org/google/

 

[Spehro Pefhany]

Complete circuit for what? To jolt the kid with 10,000 Volts?

Just wire a fluorescent in series to indicate that height > 42". Maybe
some additional ballast too so the lamp lifetime isn't compromised.


Best regards,
Spehro Pefhany

 

[Fred Bloggs]

I am a volunteer at our local lighthouse and have been asked to make a

wooden sign in the shape of the lighthouse so that they can measure the
height of children who can climb the lighthouse stairs. The minimum
height is 42" tall.

I don't have a problem with the woodworking aspect but thought it would
be a neat idea if I could incorporate some inexpensive electronics that
would sense a height greater than 42" and light a small bulb at the top
of the lighthouse.

I was thinking of a low voltage circuit that could be powered by a
battery. My talent in electronics is rudimentary.

Could anyone suggest how this might be done?

Mirrors, transient lights source actuated by proximity, and this:
http://plus.maths.org/issue23/features/criminisi/index.html

 

[Spehro Pefhany]

Just wire a fluorescent in series to indicate that height > 42". Maybe
some additional ballast too so the lamp lifetime isn't compromised.

Seriously, one way to do this safely would be to adapt a "stud sensor"
(they will detect children as well as engineers). I think they
generally "auto-zero" on power-up so that you'd need to turn the power
on with nobody nearby (maybe a pressure mat). An SSR could be wired in
place of the indicator LED (with due care paid to safety of the
line-voltage wiring-- get somebody to do this who knows what they are
doing and obey local codes).


Best regards,
Spehro Pefhany

 

[Mac]

I am a volunteer at our local lighthouse and have been asked to make a
wooden sign in the shape of the lighthouse so that they can measure the
height of children who can climb the lighthouse stairs. The minimum
height is 42" tall.

I don't have a problem with the woodworking aspect but thought it would
be a neat idea if I could incorporate some inexpensive electronics that
would sense a height greater than 42" and light a small bulb at the top
of the lighthouse.

I was thinking of a low voltage circuit that could be powered by a
battery. My talent in electronics is rudimentary.

Could anyone suggest how this might be done?

Thanks

Use a high-energy laser and an ordinary smoke detector. If you set the
laser 42" off of the ground, it will sear the child's flesh, causing the
smoke detector to go off. Children under 42" will not have their flesh
seared, and will therefore not set off the smoke detector.

To prevent prolonged searing, you may want to have the smoke detector turn
off the laser somehow when it detects smoke.

Yours in jest,

Mac

 

[Rich Grise]

I am a volunteer at our local lighthouse and have been asked to make a
wooden sign in the shape of the lighthouse so that they can measure the
height of children who can climb the lighthouse stairs. The minimum
height is 42" tall.

I don't have a problem with the woodworking aspect but thought it would
be a neat idea if I could incorporate some inexpensive electronics that
would sense a height greater than 42" and light a small bulb at the top
of the lighthouse.

It's a terrible idea. Have you ever seen a carney? (i.e., traveling
circus, but sleazier)? Admittedly, your lighthouse isn't a carney ride,
but I think a bunch of electronics to automatically detect a kid's height
is lucidrous.

Put the toy lighthouse there, and have your tour guide say, "Kids, I'm
sorry, but I'm afraid that you have to be this tall to go upstairs without
Mom or Dad holding your hand or carrying you. If you're a toddler and
couldn't care less about a lighthouse anyway, there's a play area right
over here. " (and include the smiley in the pitch. ) And provide
them with some of those oversized Legos. ;-)

Break a Leg!
Rich

 

[quietguy]

Just as an idea, but what about mounting a touch plate - 42" + kids arms
length, plus allowance for tippy toes, on a wall etc, and only let kids
who can reach to touch the plate go up. A touch plate circuit which
operates a light and perhaps a recorded message might be fun

David

 

[Paul Burke]

Supply stilts for the shorter children.

 

[Rich Grise, but drunk]

Just as an idea, but what about mounting a touch plate - 42" + kids arms
length, plus allowance for tippy toes, on a wall etc, and only let kids
who can reach to touch the plate go up. A touch plate circuit which
operates a light and perhaps a recorded message might be fun

Very bad idea - that makes it too much like a competition, and the little
kids get the short end of the stick.

The way to do it is to have a 42" tall gateway to the toddlers' play area,
and say, "You can only go in here if you can fit through this door,
otherwise you have to go upstairs with the rest of your family."

;-)

Cheers!
Rich

David

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