Sound to motor!

[sleah]

Just chucking this out there for the electronics enthusiasts if you fancy a mull over it.

I'm restoring some of my old disco lighting effects. One of which (in perfect working order) is here:

 

I have a couple of other effects that having spinning motors that rotate the halogen lamps. The problem I have is the PCB's that do the sound to motor have long since expired, at least one was missing when I bought an effect many years ago.

I do, however, have a couple of scavanged PCB's from more modern LED effects where the board supports 'bass beat-to-240v pulse', which does the bass detection nicely.

My effects use 12v DC motors where the rotation direction depends on polarity. I could just drop the 240v 'pulse' to 12v dc, but that will only give one direction of spin. I want them to do as the effect in the video, where they will (sometimes!) change direction on the bass beat.

So my thought is to use the scavanged PCB's and drop to DC, but also add in something like a M-S J K flip flop to drive either transistors or relays to do the polarity reverse. It may sound over complex, but at least one of my dead boards has about 5 74 series logic chips just to drive one motor.... so that's probably how it was done.

My other thought is to see if I can swap the DC motors for 240v synchronous motors and drive directly from the pcb's as they will randomly change direction when power is applied from the 'pulse'. I have a couple of lighting effects that work exactly like that. Swapping the motors seems the simplest option, if the shafts will fit?

I guess it's keeping me out of trouble 🙂

Edited June 1, 2023 by sleah

[themadhippy]

Personally id start from scratch as  my experience  of  cobbling  together different bits  from different manufacturers is  the magic smoke soon makes an appearance.Id go with couple of  op amps to do the beat detection feeding a counter to allow you to set the number of beats before reversal  and a bit of simple logic into an H bridge to drive your 12V motor

[sunray]

What I did about 30 years ago to put some life back into some dead lights from a night club rip out:

detect the base beat and pulse the mirror stepper motor,

 

detect high frequency beats and latch one wire of stepper motor to reverse the direction the bass drives.

I did about half dozen and son used them for his mobile disco for about 10 years.

I can't remember details but I added some hysteresis and counting or delay in the high frequency side to stop them shaking.

[KevinE]

There must be a dozen or more simple sound to light projects lurking in the Practical Electronics or Everyday Electronics mags that were published in the disco craze. Can you make something up out of one of those mags? They're all archived on worldradiohistory.com     I'm sure Tim (sabre) will be along soon as I'm sure he's designed more sound to light circuits than most! The AGC is the more complicated thing if you want to extract the beat reliably, some did it with surprisingly few parts.

Edited June 2, 2023 by KevinE
grammar x

[DrV]

1 hour ago, KevinE said:

There must be a dozen or more simple sound to light projects lurking in the Practical Electronics or Everyday Electronics mags that were published in the disco craze. Can you make something up out of one of those mags? They're all archived on worldradiohistory.com     I'm sure Tim (sabre) will be along soon as I'm sure he's designed more sound to light circuits than most! The AGC is the more complicated thing if you want to extract the beat reliably, some did it with surprisingly few parts.

Brings back memories - in the 70s one of my first 'big' projects was a three channel bass, mid, treble sound to light controller for my yoof club! Later adapted to 3 channel sequential when I learned how to divide by 3 with j-k flipflops. From little acorns... Of course from a safety point of view it was horrendously dangerous, but I never killed anyone, well, no-one ever complained that I had killed them!

[boatman]

2 hours ago, KevinE said:

.... They're all archived on worldradiohistory.com  ....

Thanks for that link. I managed to track down an article I wrote for Television magazine which was published in February 1977. I thought I would never see it again!

[sunray]

14 hours ago, DrV said:

Brings back memories - in the 70s one of my first 'big' projects was a three channel bass, mid, treble sound to light controller for my yoof club! Later adapted to 3 channel sequential when I learned how to divide by 3 with j-k flipflops. From little acorns... Of course from a safety point of view it was horrendously dangerous, but I never killed anyone, well, no-one ever complained that I had killed them!

OOOPs, glad you didn't see my lighting controls I still have from that era, they haven't been powered for maybe 25 years but H&S hadn't been invented then...

[alistermorton]

My first S-L was based around a free PCB given away in one of the electronics mags. It was only meant to drive 3 5mm LEDs but I replaced those with optoisolators and added some big triacs. 

[sunray]

On 6/3/2023 at 1:48 PM, alistermorton said:

My first S-L was based around a free PCB given away in one of the electronics mags. It was only meant to drive 3 5mm LEDs but I replaced those with optoisolators and added some big triacs. 

Oh dear...

 

My first S/L kit was before LED's were viable due to the cost and they were only red.

[sleah]

Thanks for the ideas/thoughts and especially the anecdotes 😁 , it's given me something to think about.  I'm in no rush, it could be months before I revisit.  I've already converted one that used a single dc motor to a 240vac motor and added a pcb as-is. Works a treat👍

Oh, nearly forgot, whilst tinkering, one of the PCBs decided to go pop, that lovely sound of a 240v short. Good sound, even if it does take 10 minutes to get back in to my skin afterwards 😂

May have been a strand of wire I missed, took the ring main breaker out and left a great skid mark on my workbench.

[DrV]

1 hour ago, sleah said:

left a great skid mark on my workbench.

You shouldn't have been sitting on the bench in the first place...

[sunray]

11 hours ago, DrV said:

You shouldn't have been sitting on the bench in the first place...

or not wearing anything😁

[sleah]

Look, what I do behind closed doors is none of your business.

.

.

.

I still can't sit down....😆😆

Edited June 5, 2023 by sleah

[alistermorton]

14 hours ago, sunray said:

Oh dear...

Why "Oh dear"?

[themadhippy]

Quote

My first S-L was based around a free PCB given away in one of the electronics mags.

too complicated,mine was a torch lamp wired to the output of my first ever record player.