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View Full Version : [Question(s)] As Slow As Possible. Seriously.



draikani
04-17-2010, 11:39 PM
This will no doubt seem like a very strange request to some of you. Im loooking for some type of linear actuator that moves very slowly. For example if I looked at it I don't want to be able to tell its moving, but if I came back in an hour or so, it would be nice if I could tell that it was in a slightly different position. I know this post is pretty vague, but I haven't decided exactly how I'd like to implement my idea yet so I didn't want to stifle any of the excellent ideas you guys will undoubtedly have. :happy: I can tell you however that it will need to be absolutely silent and consume very small amounts of power. I considered using muscle wire, but I'm not sure I can get it to move as slowly as I would like. Thanks in advance!

Robonaut
04-17-2010, 11:57 PM
A clock. The hour gear moves fairly slow and quietly. You didn't mention torque requirements or any thing else so, A clock. Given the right clock you could probably gear it even slower.

draikani
04-18-2010, 12:14 AM
Torque requirements would be quite low. I just need it to pull a string that will bend a rod. The rod will not be stiff at all. (If anyone would like this described better I'll do my best.) I assume by clock your are just suggesting I use a small DC motor geared way way down? And I suppose it could just turn a spindle to convert to linear motion. Also worth mentioning I only need it to move maybe 1-2cm.

Robonaut
04-18-2010, 12:27 AM
Actually I meant a clock. Yes convert to linear motion. But if more torque is needed, gearing down motor or servo may be the way to go. Or use a clocks inners. Would have to be a sturdy clock. Also this link maybe be helpful.

http://answers.yahoo.com/question/index?qid=20090904225903AAuaYyQ

I have never tried any of the above. Just throwing thoughts out there for you.

Robonaut
04-18-2010, 12:40 AM
This site looks like it has a good variety of clocks inners.

http://www.clockworks.com/

draikani
04-18-2010, 12:49 AM
Thanks for the quick feedback! It might work, maybe a little more complicated that I was looking for though. Would like to get some other ideas coming in before I do any sort of deciding though. My other reservation about using clock innards for this is that they are very precise, which means the cost more. I basically need them to be either pulling the string, or not pulling the string, so I do not need any accuracy at all.

Robonaut
04-18-2010, 01:06 AM
I found this also

http://cart.clockparts.com/font-colorbrownquartz-movementsfont-high-torque-movements-c-21_40.html

It's the whole deal. Power, motor and all. Claims they have high torques. Not sure it can be much simpler. Small dimensions around 2 1/8" w x 2 1/8" h x 5/8" d. Several to chose from.

Most seem to be priced under $10.00

Not trying to hog this thread, it late, I'm bored. hope it helps.

draikani
04-18-2010, 01:17 AM
Not at all man, we are in the same boat. nothing going on tonight. And of course any information you can provide is better than the info I don't know. Was really hoping to find someone with some experience with flexinol (muscle wire) because if I could activate it slowly it would be ideal. The clock idea is growing on me though... especially if I could get something small, like from a watch.

zoomkat
04-18-2010, 01:38 AM
You probably need to give some specific details on your requirements such as:
1. How much movement do you want in a 1 hour period?
2. Is the movement stopped after a period, and if so, what is to happen then?
3. How much force is expected to be applied?
4. How is the device to be powered?
5. What are the size requirements for the device.

Asa side note, muscle wire takes a lot of power.

draikani
04-18-2010, 02:01 AM
Alright then...

1. How much movement do you want in a 1 hour period? The idea was to have a thin flexible rod with strings attached to 4 sides. When a string gets pulled on the rod bends maybe
30 degrees to one side (this would happen over the course of an hour).
2. Is the movement stopped after a period, and if so, what is to happen then? Movement stops once the rod has bent.
3. How much force is expected to be applied? only enough to bend the rod. Im really not sure what material to use, maybe a little piece of balsa wood or carbon fiber, like the stuff used in a kite frame.
4. How is the device to be powered? Solar power, so power use must be minimalized. I haven't done the research on the panels yet, but I won't have more than a few watts incoming. However I can configure this into any combination of amps/volts I want, I think it will probably be about 3V at maybe an amp or so.
5. What are the size requirements for the device. would like it to fit in a 4"ish cube, not including the flexy rod.

All numbers are extremely rough estimates. And how much power are you talking zoom?

I think I should also mention that it is not at all necessary to bend the rod using strings, I just though this would be easiest. So I'm essentially looking for a low power way to make a rod bend different directions.