The business I work for is looking to ‘jiggle’ an art installation that we have been commissioned to build. The art piece consists of pieces of brass and brass chain suspended from nylon wires. Each piece is no more than 2kg. Our plan is to conceal vibration motors in the roof mounts and attach these motors to the nylon wires. We will also attach a potentiometer to adjust the shaking of the motors.
What vibration motor would best suit our needs? Those being: Must be a small concealable unit, capable of vibrating a 1-2kg weight, and be able to attach to or receive a nylon wire.
Concealing vibration motors shouldn’t be too hard as most are quite small. A lot of these motors vibrate at around 10,000+ RPM so it won’t produce a noticeable jiggle, they are more designed around user feedback, like the vibration in a smartphone. You may need something slower that moves a greater distance to get a vibration that is noticeable to a viewer.
Ultimately a vibration motor is just a DC motor with an uneven weight attached to it. This motor shows the design more obviously than some of the button-shaped vibration motors.
Yeah spot on with a smaller motor such as that one.
Do you have a rough sketch of the installation itself? and where you intend to put the motors?
Will it be jiggling up and down or side to side?
From a control point of view this is an interesting problem as trying to oscillate the piece outside of its natural frequency will be quite difficult and require far more power. Matching the RPM with the motion of it will allow you to use a smaller weight (not quite as small as the one Trent linked).
Also depending on the nature of the movement and the design you go for, parts could wear out if its running for extended periods of time.
I think that 3V hobby motor will struggle to move 2kG from a standstill. The weight will probably stay still and the motor move.
Are you sure this is the way to go for this task. Most motors I have seen of this type have been attached to a shaker table. The motor shakes due to being grossly out of balanced and in turn the table shakes because the motor is bolted to it.
I just can’t picture how you intend to “jiggle” this weight using this system as by its arrangement the whole motor is going to shake.
This an an example of a geared motor that can be driven from a simple DC supply.
If you added an eccentric on the shaft you could run the suspension string across (or around) the rim of the eccentric to create an oscillating motion in the string of about the right frequency for a jiggle.
A potentiometer would work, but it might be difficult to find one with a sufficient current rating, and it wouldn’t be very efficient. The best solution would be a 12v plugpack combined with an adjustable power supply, such as:.
I don’t know if you noticed my edit, but I linked an Aussie supplier who has some in stock. Keep in mind you’d also need something that can generate your audio signal, and an amplifier to drive it. Let us know if you need a hand with those parts of the project.
Agree but I don’t recollect 12V being mentioned anywhere.
I bought this up because there have been cases (on this forum too) where the interpretation has been that you can have any input within range and get any output in the published range which is quite wrong. This really only boils down to not reading the published description fully and carefully. But it happens.
This is the way I would go with a suitably geared motor. The only reason you would want the whole motor shaking would be if you were making a shaker table. That would probably work if you ATTACHED ALL OF THE LINES TO THE TABLE, not to the motor. You might require a bit larger motor than the small hobby style inits though as you need to shake the whole table. If you found a resonance with 2kG weights hanging off it some of the results could be pretty spectacular. Some of the large bridges that have come down in the wind due to resonance being reached come to mind.
EDIT. Jeff, I apologise I just found your reference to a 12V plug pack.
@Barnaby175515 I think you’re actually a little off track with vibration motors when you’re looking for something that will jiggle. Vibration motors will vibrate things at frequencies of at least 10Hz (10x per second), and most of them much faster than that (above 20Hz you start to get into an audible buzz).
If you’re looking for a “jiggle” that says to me at most ~2Hz which is an order of magnitude slower. For this you need a motor that spins about 60-100 RPM, and I’d just use a crank to create the jiggling using a standard motor:
Like this (But instead of the slotted yoke, tie your string to the wrist pin).
One thing I’d watch out for is wearing through the string - it’d be a good idea to tie a longer backup string in case the string wears through so it doesn’t all come crashing down, like this:
Edit: One other thing to watch out for is resonance - if your motor happens to be close to the resonant speed of your dangly thing and length of string, your jiggling might get out of hand but you’ll notice that pretty quickly in testing. To fix it you just need to change your length of string, or speed of your motor.