Rotating light? HO and smaller scales

[Southwest Chief]

I've been toying with the idea of animating a spotlight for my HO scale movie theater.  I thought about using a motor to spin the light housing and adding a super bright LED to light it. 

I'm looking to duplicate the look of these old spotlight/searchlights see in the video link below:

Video Link

Here is the spotlight trailer on the layout, currently with no light or animation.

Adding a motor to spin the housing is easy.  Adding an LED to light it is easy.  But combing the two has stumped me.

I can't figure out how to prevent the light (LED) wires from twisting around and around as the housing rotates.

Can anyone help me with my brain cramp?

[richg1998]

Rotate the light 180 degrees using a Tortoise with a bell crank under the layout. A rod up thought the layout and connected under the light fixture. I cannot see the bottom of the light trailer so this is just a guess on how to attach the rod. Use a lower voltage for the Tortoise speed which suits you.

I would use a 555 timer IC timed to operate a relay to switch polarity to the Tortoise motor.

Use #40 magnet wire for power to the LED in the housing. This enameled insulated wire is quite small. Even #44.

No doubt others will have comments.

Rich

[hornblower]

Many such lights simply rocked around a central pivot instead of rotating for the same reasons your miniature version cannot rotate.  A little research might be needed to come up with a rocking mechanism but I would imagine that two push-pull rods attached to the light housing, offset 90 degrees from each other and operating 90 degrees out of phase would give the desired rocking effect.  A stepper-type or highly gear-reduced motor could be used to drive the push-pull rods from under the layout.  Some ultra-flexible decoder wire could then be used to connect the LED through the central pivot.

[Southwest Chief]

Appreciate the responses. 

I spent some time researching on the internet and found something called a "Slip Ring".  This device allows wires to rotate. 

If I can find a really small slip ring, this might...might being the key word here...allow me to rig something up to rotate the light.

Another thing that has been somewhat difficult has been trying to find out how the older (1950s) era spotlights rotated or moved.  I can find lots of modern era spotlight videos showing how they rotate and move up and down.  But it seems the vintage ones simply rotated.  Best videos I've found are these:

Spotlight Video 1

Spotlight Video 2

[farrellaa]

That was my first thought, a slip-ring to allow the LED to remain connected to the power while it rotates 360 degrees. The other thing you could use is a stereo jack and plug where the LED is mounted to the plug and the jack has the power connected to it. Then you need to apply a low rpm motor (3-6 rpm) to turn the plug. This would be the cheapest and possibly easiest way to do it.

     -Bob

[Texas Zepher]

Could you make the LED and its wiring stationary and just rotate a cap, mirror, or lens over it?

[rrinker]

A Tortise, two microswitches (or if you don;t care about warranty, cutting the traces inside the Tortoise so the contact only engage near or at the end of the throw) and a relay would accomplish all that is required electrically. You'd either need a DPDT relay plus a bi-polar power supply (as shown in the Torotise wiring diagrams - one set of relay contatcs would repalce the SPDT toggle - the other set of relay contacts would be used to make a 'stick' circuit) or a 3PDT relay, with one pair wired like a DPDT toggle for reversing and the extra contacts used for the 'stick' contacts. Basically, apply power, the tortoise moves to one side, hit the microswitch which engages the relay, revering the pwoer to the Tortoise. The stick contacts keep the relay held in, until the Tortoise hits the other microswitch which interrupts the power, relay drops out, Tortoise reverses. Adjust drive voltage to vary the speed of the searchlight sweep.

            --Randy