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Lighthouse beacon for yard lighthouse

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atferrari

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atferrari

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I guess she'll just have ships crashing in her backyard then
:nailbiting::nailbiting: :facepalm::facepalm: :p:D

Salvaging one from a crashed cop car maybe is an option. Ready made.:)
 

dr pepper

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I have a garden ornament thingy which has a led and a rotating mirror, the mirror is rotated by what looks like a clock movement, only much faster, you might be able to get the movements off ebay, or how about a cheapo mirror ball rotator.
 

atferrari

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I have a garden ornament thingy which has a led and a rotating mirror, the mirror is rotated by what looks like a clock movement, only much faster, you might be able to get the movements off ebay, or how about a cheapo mirror ball rotator.
Small stepper?
 

MrAl

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MrAl

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I would like to know how to build a rotating light beacon for a yard lighthouse.
Hi,

Nice idea.

Rotating electronic things are a little harder to make than electronic non rotating things.
One idea if you could accept it, would be to have multiple high power LED's arranged in a circle pointing outwards, then turn one on at a time so as to make it look like one is rotating. The more LED's the smoother the action.
The main point is that the reliability should be much higher than a mechanical movement.
 

AnalogKid

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As Ex said, a clock and a 4017 get you most of the way there, but there are two problems. First, the 4017 can source only about 4 mA, which is enough for late night visibility but a bit weak for evening. Second, the LEDs snap on and off crisply rather than appear to fade up and down. To fix both, try this:

For each of the 4017 outputs, add a series resistor, shunt capacitor to GND, and a MOSFET such as a 2N7002 as a source follower to drive each LED. With the right component values, each FET will have an approximate triangle wave at its gate. Each LED will ramp up to its peak brightness, then as it starts to ramp down the one next to it will start to ramp up. This should be much closer to the sine-squared brightness profile of a single rotating point source of light. Depending on the beam width of the LEDs there will be an optimum distance for the rotating effect.

A 0.5 s clock period will produce a 5 second "rotation", which feels about right for a starting point.

ak
 

AnalogKid

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Something like this. Only one output stage shown, no decoupling, no power conditioning, etc. Vcc should be 9 V or greater. Modify R3 per the specs for the LED.

ak
Lighthouse-1-c.gif
 

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dr pepper

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Its a long time back so the video is bad as I had a cheap camera, however I built this for a lighthouse the mrs turned out of wood, it looks good in the lighthouse.

 

MrDEB

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Analogkids idea is viable but cascade 4 4017s together for a really smooth rotating effect. A pic using mosfets would be the best solution. Then only 1 micro is needed and chariplexing the leds.
 

MrDEB

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here is a actual working schematic plus I think I have a couple of extra pcboards un-populated.
This design has a variable speed adjustment as well. You just need the parts and the pic programmed. This only has 20 outputs.
 

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ronsimpson

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Hope this video works. If not. post #19, go to link, go to bottom.
Think on this: 5 LEDs facing different directions. All LEDs are driven with the same current and produce the same light. When five people standing around the light house, they will see the same thing at the same time. They will think the light moves in a circle but it does not. (fake and in your head)
LED current timing, 0,0,0,0,1,2,3,4,10,10,4,3,2,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0, repeat.
Watch the video and think "not spinning". Now think "spinning".
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You can make 5 LEDs do the above pattern 1/5 out of phase. I think each person will see the same thing as above.
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What do you think. Does a stationary light house rotate in your head because you are programed to see it rotate.
 
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