As opposed to around?  Anyone have any ideas?  I've never really worked with motors at all...  Any ex-engineers got any ideas?

-Colin

You want to build an auto-drive/total recall mixer?
There's ways to get stepper motors to create (within a certain distnace) a linear displacement, there's ways to propell stuff linearly over undefined distances, but the technologies are miles apart.
What exactly do you want?  An electro-magnet with a cast-iron bar in a tube could be considered a linear motor in certain conditions...

Not really sure what you're looking for, but you could take a circular motor and mod it to propel and object up and down.  For example, a home spun tatooing gun.  You'd take the motor with an circular orbiter, solder or JB weld a pin on the far end of it, and attach a rocker arm to it with a washer or some such and cap off the end so the rocker arm doesnt come off the pin.  Make sense?  Hope it helps.

It depends on what you want to do and how much control you want. What you are asking for is a linear actuator. You can either use a motor that does it in one device or rig up some mechnical system similar to a wah pot gear mechanism except the pot is a motor.

If you just want to travel a certain ditsance thats easy but if you want to control the posistion you would use a stepper motor. Then you would need the control system for the stepper motor. Then if you want to recall different posistions you would need a computer system with memory and maybe some kind of sensor/feedback loop to tell the computer where it is. And so on.

What do you want to do ?

Andrew

put it in an elevator or something, and it'll go up and down...

(sorry, that was bad)

The 'sewing machine' tremolo...

Penny&Giles and Alps make motorised faders but control circuits are needed of course.

No no, the reason it's off topic is because it's not for audio  For an idea my girlfriend and I have, if it goes anywhere I'll show it off

Hmm... a linear actuator, eh?  I don't mean like an automated slide pot, I mean like a pumping motion.

-Colin

How fast do you want it go ? How much force does it need to apply ? These factors can affect what mechinism you will need to use.

Andrew

Don't they make servo motors with that kind of motion? Like a rack and pinion?

You could attach one to a diaphram that pumps a plunger or piston in/out.

if you're near a radio control model store, check out some of the servo and actuator setups for rc cars and airplanes. you could probably hack something together pretty easily.

clay

a solenoid?

a spring-loaded solenoid would work, yes! Mayhaps a bit violently, but it will work

Quote from: anonymousexperimentalistNo no, the reason it's off topic is because it's not for audio :)  For an idea my girlfriend and I have, if it goes anywhere I'll show it off :)

Hmm... a linear actuator, eh?  I don't mean like an automated slide pot, I mean like a pumping motion.

-Colin

waaaaaaaaaaaaaaaaaaaaaaa????????



edited..  just so no one bitches as me and gets mad i am not impliying anything here only asking waaaaaaaaaaaaaaa  as i can't visulize the purpose wihtout knowing

Pumping motion for your girlfriend eh

Ghehe what you should look at is a crankshaft of a combustion engine and see how that's done. You could use a rotating motor do (ahem) pump a piston up and down like that

Try here for a start http://www.robotstore.com/  You could probably use a servo with a gear box or even some muscle wire (great stuff). It just depends on how much torque you need.  Smaller servos aren't going to move a lot of weight around.

AL

How 'bout this?

http://www.saroftreve.com/tfm/invader.htm

:twisted:
-alan

It certainly shows the mechanism well :twisted:

I'm thinking rack and pinion; it's smooth and â€"potentially- simple. However you would need to be able to reverse the motor and have some kind of limit switch so you didn't strip the gear at the end of the rack's travel.

Got an air compressor? You could use a pneumatic actuator...
Sorry, I had to.  :wink:

Some sort of rack and pinion or worm gear drive could maybe work. The limit switch would be a good idea. It wouldn't be too hard to make a circuit to reverse the motor.

Those little servos in stuff like RC planes could work, they are compact, too.

You could maybe use something like the pulley system in the Ernie Ball volume pedal.