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micro motion Answered

I all of a sudden got into beam bots as a project to do when I'm bored, anyways what's the smallest device to get motion? THe device also can't be power hungry. would muscle wire work? how many amps do they take? does anybody know how to wind their own micro solenoids?


ok, I've been searching, and does anybody know where to get the .001 inch diameter flexinol? I don't want to buy from dynalloy because I either get a 10 dollars handeling fee, or I spend at least 50 bucks, which I don't want to do, inless someone want's to go in for a group buy.

thanks for the links, do you know what the difference is between the low temp and the high temp flexinol for an electric application? According to the flexinol datasheet they're hte same, just that the high temp relaxes faster.

The higher the temperature of the wire, the faster it will cool off when you remove the current, because the temperature difference between the wire and surrounding air will be larger. That means that a wire with a higher transition temperature will tend to go through the transition zone faster when cooling off, i.e. the wire will relax faster, and will be able to switch back and forth faster. The new HT wire is a little more expensive and can run very hot (Activation Finish Temp is 98 Celsius - almost boiling). Looks like the 25 micron wire is only available in a LT version - possibly because the very fine wire is too easy to overheat and burn through.

Dunno - a figment of your imagination perhaps? :-D I just based that assumption on the specs available from robotstore.com. I guess their information is outdated...

Is there a datasheet for flexinol? I'm not sure what gauge to get, the smallest gauge is .0015 inches, or 38.1 microns, or thinner than 40 gauge. According to my calculations it'd take about 30 mA but I couldn't figure out resistanace. I don't know how many grams it could hold before snapping, because 38.1 microns is PRETTY thin.

never mind, I found it, it was hidden in the dynalloy page

thanks guys, I think I'm going to go with the flexinol wire because it can be cut up to make a bunch of tiny motion devices (smaller than motors) and take up about the same amount of current.

Don't forget that their motion is only about 4% of their length - a 5mm length will only shrink by 0.2mm.

I prefer putting a similar jig in a cordless drill. It goes MUCH faster, and is WAY neater.

Like the old saying about a cat, there are many ways to wind a coil LOL

Pager motors are popular, and some of them (Tamiya?) are the size of a Smartie M&M.

Muscle wire - according to this UK site, the activation current can be as low as 50mA or as high as 2.75A, depending on diameter. Remember that the wire needs to be under tension to regain is shape as it cools. Google for Stiquito to see a simple small robot that is moved by muscle wire.

For the solenoid, I'd just wind a load of enamel wire around a straw or paper tube to the size you need.

(If you haven't already, have a look at Junkbots, Bugbots and Bots on Wheels)

do you know od a place to buy it for the US? If I were to buy it from there it'd cost 20bucks for 1 meter.

hmm..I think the smallest robot in the world is not much more than a piece of silicon that jiggles when they run electricity through it. That might be a bit too small for you though. CD players contain some pretty small motors that could work for you.