Identifying a vintage lighting sequencer method

Question

In India, on certain social festivals like Durga Puja, Kali puja etc, lighting decorations are done around roads etc, where various themes or stories are animated (such as stories from Aesop's fables), using a complex array of chaser light techniques.

Nowadays these chaser effects are done on LED lights using sequence generator chips or ICs. Back when I was a kid, say in the early 90's, the task was done in an entirely different way. There was a big motor (usually a ceiling fan motor) attached with a drum-like structure, and there were and some carbon brushes connected with that drum looked somewhat like this:

When the drum revolved, the unevenly placed conductive plates touched the carbon brushes at a different time-period, it resulted in switching on associated light series. I still can see in my mind's eye the falling sparks from the carbon brushes.

But unfortunately after web crawl through several years I couldn't found a single blog mentioning this vintage lighting technique. When I ask people in person, I see most people forgot it or may be they never noticed it. The laypeople who sewed the stories on iron grids were mostly uneducated poor people, seemingly blogging was not possible for them. I wonder how a wildly popular technique can just be forgotten.

My question is:

Is there a name for this mechanical sequence generation technique?

Prior research

I have thoroughly searched wikipedia and other internet websites.

I also asked my dad who told me the "drum" like portion were probably a bit more complicated than this, containing some gears that reduces the speed of switching. I found some blogs that mention use of relay switch as a sequence generator, but I really did not find any mention of motors as sequence generators.

Confession and request

Our family got our first camera in around 2007 (which was a Kodak film camera,) when this lighting technique was already obsoleted, so we do not have any photographs of this technique. If anybody has a picture of this technique, please add the photograph and a permission to reuse.

See also:

Modern day version (LED based) of such lightings:
https://www.youtube.com/watch?v=gV72RqjA-4A
https://www.youtube.com/watch?v=BfbLxQVMpOI

Answer 1

http://www.nanditapalchoudhuri.in/sholapith/chandlights.html

The blog provides almost all the details.

The circuits are powered by an indigenous mechanism-a simple table fan motor that turns a roller anchored by an elastic band. Each of these motors can run 4-5 simple circuits.

The gallery section of her blog includes a photograph (image 14 of 21)

The school of craftsmanship that used this kind of technique is mostly from Chandannagore, West Bengal, who prepared the stuff for Jagadhatri Puja festival. How did the uneducated (probably illeterate) and poor laypersons planned out the animated motions out of light bulb matrix, and how they did connect the groups of bulbs to that switching system, is truely ingenious. This is an example of the Beta Phenomenon, phi phenomenon, and a hierarchical arrangement of these illusions.

Following is a circuit outline of a safe DIY project with LED lamps and 12V DC motor that uses only 6 groups of LED to create an illusion of an infinite series of successive ripples.

Happy enjoying Chandannagore Lights arts!

Answer 2

Yes - a cam timer:

https://en.wikipedia.org/wiki/Cam_timer

I'm not sure what other detail you're looking for.

Answer 3

This concept is sometimes called a "Drum Sequencer" or "Mechanical Drum operated switch" which has a lot of implication in electronics other than decorative lights.

Ancient Persian scholar Banu Musa is credited for inventing a hydraulic Music drum much similar to this but purely mechanical. It is often considered as an earliest type of computer program, often compared to Jacqard's loom.

The Banu Musa Automated Music Sequencer

Source: The Forgotten History of Repetitive Audio Technologies, by Christophe Levaux

Similar techniques still used by the band Wintergatan.

This technique has been adopted into early version of computation such as PLC or programmable Logic Controller.

Mechanical Drum operated switch

image from Norhampton Community College Slideshare Notes.

The modern simulation of drum sequencers are still used such as following technical data sheets and instruction manuals of some controllers.

Datasheet of an electronic controller

and

Drum sequencer Utility

(from https://www.unitronicsplc.com/Download/SoftwareHelp/U90LadderKnowledgebase/Drum/drum_sequencer.htm)

etc.

Interestingly, at the 70s to early 90s, similar kind of mechanical sequencers had been widely used in Indian decorative and festival lightings which was a cottage industry.

Although exact photograph of 90's wooden roller machines are not available in the internet, many people still uses the technique which is available in youtube

Making an analog chaser light

DIY Chaser light without a circuit board

Light chaser at home

how to make light chaser at home

Special lighting for home decoration

6 channel light chaser at home

Caster Chaser machine

Jhalar (fringe) machine ... it uses PVC tapes on a metal can as a negative mode of above drums.

Chaser at home.

And countless other attempts are there in the youtube following the exact same mechanism.

(Warning: Although most of these DIY youtube methods are hazardous for children as the AC home power supply voltage is often directly applied on the open barrel, I just mention them for a historical tradition. If somebody want to replicate a lower voltage version projects of this, or just to use it as a controller inputs that is another case)

Recently several commentators on newses regarding histories and the blog post on light makers of Bengal,

90s incandescent bulbs wrapped with coloured cellophane paper

has been credited an electrical technician Sridhar Das for designing such device, although they used various names like "Wooden Roller", "machine for chanelling lights" etc.