Lighthouse spinning light

Euan Thomson · May 6, 2022

Hi guys, I’m looking for advice. I’m trying to figure out how to replicate a rotating light in a customers lighthouse. Had a look at spinning beacons but obviously they would be too fast. The lighthouse is glass fibre and hollow up the middle with just over 300mm diameter in the Perspex head to fit a light so getting a cable up would be no bother. I’m just struggling to find anything that could spin slowly like a real lighthouse.

[ElectriciansForums.net] Lighthouse spinning light

pc1966 · May 6, 2022

Generally speaking, if you want slow rotation (as in tens of seconds per revolution) you will need to gear a motor down to drive the reflector.

Small DC motors are easy to speed-regulate by adjusting the voltage which would help, but generally they have shaft speeds of a thousand rpm or thereabouts, maybe adjustable to a few hundred, so you would need probably two or three stages of gearbox to bring it down.

Something like this has a fairly slow speed at full voltage:

https://uk.farnell.com/micromotors/b138-f-12-1470/motor-geared-12v-1-6rpm/dp/1784828

You might find a clock mechanism that is cheaper, etc, but maybe too slow in that case.

pc1966 · May 6, 2022

Or cheaper / in-stock

https://www.amazon.co.uk/Torque-Turbo-Geared-Motor-100RPM/dp/B01LXV085F/ref=sr_1_1_sspa?th=1

pirate · May 7, 2022

That's a good shout @pc1966
I actually need just such a motor for a project and was eyeing up my Garrard SP25 Mk4 (younger viewers can ignore this!) with a view to altering it...but now I have just what I need!

marconi · May 7, 2022

Alastair Campbell holding an LED torch?

I will try harder with some potential ideas.

A few Qs:

1. What is supply voltage and frequency?

2. Is it complete top structure which rotates or just the metal axle one can see through the perspex?

3. How bright? Do you want a 'flash' of light as it swings through a bearing which would require some lenses or reflectors to direct the lamp light?

Rockingit · May 7, 2022

You can buy an off the shelf rotator designed to spin theatrical mirror balls with a few quick searches - I'd suggest a 4rpm one would be about right. All you'd need to do then would be to figure out how to mount a 650W DWE style lamp onto it which I'd guess you could do by butchering anything which already has a brush/ring arrangement - maybe an old motor armature.

This sounds like a fun project.......if you have the time!

Euan Thomson · May 7, 2022

Thanks for all the input guys, definitely gave me more ideas.
@marconi input voltage will be 240v 50hz fed from an outdoor socket initially and was thinking of using a click remote to switch on and off. There’s the option of fitting a control box out with the lighthouse. The metal axle you see is a bit of threaded rod that is connected to the very top and through to the base. The base connection has fell off so I was thinking of removing the rod completely and fixing the base to Perspex to top. As for brightness and lenses I was thinking the simpler the better as it is only sitting in the customers enclosed garden.

marconi · May 7, 2022

Lawn Lighthouse Revolving Beacons - The Lighthouse Man - https://www.lighthouseman.com/lawn-lighthouse-revolving-beacons/

Beacons Lighting | LED Beacon Lights | RS Components - https://uk.rs-online.com/web/c/automation-control-gear/automation-signalling/beacons/?applied-dimensions=4294572604

ian.settle1 · May 7, 2022

Barbers pole light might be the right speed

sparkymark77 · May 9, 2022

How authentic does it need to be? Something like a speed adjustable strobe light mounted just below the Perspex top would replicate the flash every few seconds and would be pretty simple with no moving parts.

captaincaveman · May 9, 2022

Cheap to run and environmentally friendly?

marconi · May 10, 2022

Euan Thomson said:
Thanks for all the input guys, definitely gave me more ideas.
@marconi input voltage will be 240v 50hz fed from an outdoor socket initially and was thinking of using a click remote to switch on and off. There’s the option of fitting a control box out with the lighthouse. The metal axle you see is a bit of threaded rod that is connected to the very top and through to the base. The base connection has fell off so I was thinking of removing the rod completely and fixing the base to Perspex to top. As for brightness and lenses I was thinking the simpler the better as it is only sitting in the customers enclosed garden.

If it was me I would only send safe 12V along the cable to the lighthouse and keep 230V - 12V double insulated conversion inside a box on the wall or inside the building.

Avo Mk8 · May 10, 2022

A possible 12/24V option if you could wire the motor separately from the bulb, to a lower voltage, or a speed controller
(and ditch the cover!)

12V 24V Rotating Amber Beacon Light Lamp Lorry Car Van Tractor Forklift Digger | eBay

12V 24V ORANGE AMBER ROTATING. RECOVERY HAZARD LAMP BULB INCLUDED H1. With Protection Cover. Simple design and easy to use. Permanent Mount : 3 Bolts. Bulb Included (H1).

www.ebay.co.uk

The drive reminds me of the early Japanese "toy" tape recorders -no capstan - just driving the spool!

Euan Thomson · Jun 7, 2022

Update.
The lighthouse is fully functioning. Got a IP rated 12v beacon and wired up the motor to a speed controller, however it was still too fast. Replaced that motor with a geared motor however the base needed modifying to hold the motor, oh and the motor shaft also needed turned down on my dads lathe to work. Fitted a 24v lamp to the beacon and kept all the power supplies inside an IP junction box with a click remote and receiver switching the power to the box.
I haven’t seen it working in the dark but the customer says she can see it from the opposite side of the garden, the garden is huge at least 60m. Hopefully get a video from them soon.
Thanks for all the input guys it’s very much appreciated, sparks truly are the finest trade.