looking for suggestions on actuator grid

[thule]

Hi folks

I have a small question. I am trying to design an actuator grid. It needs to be around 2x3in. I want to put around 50x40 = 2000 tiny actuators on it. These will be handled by a pi or an arduino possibly using a few shift registers.

I have been looking at options including piezo, electromagnetic coils. I have Rochelle salt and planning to make a crystal and then cut it to make small rods to make the piezo.

These need to be able to respond around 100hz or less. Range of movement required is a few mm or less. Low power consumption will be a big help.

Any ideas? I am a newbie and am kind of stuck at this point.

Thanks

 

[thule]

No takers?

I have been reading more and came across electrostatic devices. However these seem to be in the micrometer range than what I am looking for.

Any ideas? Thanks

 

[BradtheRad]

Earphones are the closest thing that comes to mind. The inexpensive kind that fit in the ear canal.

These have a small coil of wire, and a metal plate over the top end. The audio signal is AC current. This creates a magnetic field which vibrates the metal plate a tiny distance.

Suppose you take one of these, remove the plate, and put a tiny rod inside the coil. Then you have a solenoid.

 

[thule]

Earphones are the closest thing that comes to mind. The inexpensive kind that fit in the ear canal.

These have a small coil of wire, and a metal plate over the top end. The audio signal is AC current. This creates a magnetic field which vibrates the metal plate a tiny distance.

Suppose you take one of these, remove the plate, and put a tiny rod inside the coil. Then you have a solenoid.

Hi there

I was thinking of that as well. However my application is to create a grid of several of these as a small panel - likely to be upwards of several hundreds. I am also hoping to be able to integrate the making of this once the prototypes are done. That is why I was looking more for voltage driven than current driven considering the number of the actuators and also the portability needs requiring battery operation.

Thanks a lot.

 

[BradtheRad]

Since you mentioned piezo devices, you probably know about piezo fans which move back and forth. Possibly as fast as your spec frequency of 100 Hz.

I can't advise about amount of motion, power requirements, etc. I picture you might remove the paddle piece, leaving you an actuator of some sort.

 

[thule]

Since you mentioned piezo devices, you probably know about piezo fans which move back and forth. Possibly as fast as your spec frequency of 100 Hz.

I can't advise about amount of motion, power requirements, etc. I picture you might remove the paddle piece, leaving you an actuator of some sort.

No, I haven't heard of peizo fans before but I guess they are a type of amplified actuators. I am looking at these now. Also, what do you consider to be a good workable material to make piezoelectric blocks out of - I am thinking of PVDF - I can form it and then use the triad of heat/stretch and high DC voltage bias to pole it.

Any other suggestions will be greatly welcome. I am new to all this and am learning as I go along. If I make any dumb plans/suggestions please do correct me.

Thanks

 

[thule]

Hi

Is it possible to use SMD inductors to cause actuation? I mean if I stack two inductors one on top of other and supply current in opposite directions will they repel each other?

Thanks

 

[BradtheRad]

Hi

Is it possible to use SMD inductors to cause actuation? I mean if I stack two inductors one on top of other and supply current in opposite directions will they repel each other?

Thanks

In principle it will work. I almost asked why one of them can't be a magnet. Then I realized a lot of neighboring magnets would interfere with each other.

A moving inductor will move its connecting wires too. Eventually a wire will break.

It might be of interest to learn about dot matrix print heads. These contain several solenoids spaced a small distance apart. Each one is independent, pushing a wire a small distance to punch against the paper. I'm not sure whether the wire is pulled back by spring action, or by the solenoid.

 

[thule]

Did not realize about dot matrix heads. Will look those up. I am also looking up on 3d printing inductors. I am not sure how multi layering and insulating turns of copper will work.

Thanks