I'm new at this, I dont know where to start, any tutorials online that deal with muscle wire, and controlling the amount of current running in the wire?
thanks for info
It all depends on the diameter of the wire. This chart should help.
http://www.imagesco.com/nitinol/wire.html
As with all electronics if you want to limit current flow you'll need to use a resistor. How you calculate that? I don't know. This is a guess so correct me if i'm wrong. If we refer to the chart and use 1" of the 0.0010" diameter wire. It has 45 Ohms of resistance and will pull 20mA. So i figure we treat it kind of like an LED. Resistance multiplied by Current gives use the wires voltage which is 0.9V. So if we treat it like an LED to calculate what resistor we need then we have this. Take a 5V power source, it has a drop voltage of 0.9V and pulls 20mA. So you'll want a 205 Ohm resistor on it.
Does that make since? How far off am I on this?
Here's some info:
Basically, it seems you treat it like you would control a solenoid, relay, or motor - you can use a relay to control it, or a high-current transistor or MOSFET. Do some research on how to control a motor or relay (simple on/off) with the Arduino, and you should be able to adapt those schematics and code to control the muscle wire.
Be aware that the wire gets hot, and don't burn yourself (check out in that link above what that girl did to her dress - ouch!)...
i have a .5mm wire
should I use a
variable voltage output AC adapter ?
Well looks like i wasn't too far off though the logic was a bit odd wasn't it?
should I use a
variable voltage output AC adapter ?
Any DC voltage input will do. Just be sure to get the resistor figured out correctly. So like it says in the link cr0sh gave.
The equation to work out what resistor you will need in series with your wire is :
resistor (Ohms) = (power supply(Volts) /current required to make the muscle move(Amps) ) – total resistance of the muscle (Ohms)
So refer to the data sheet on you wire and plug in your numbers.
Looks like it may be the muscle wire inside another material. Not sure about the membrane under it.
is the muscle wire continuous in this sketch?
Yes... they just "crimped" it... so maybe it's attached to something they want to have "moved" at the point it is crimped.
Looks like 2 wires crimped together. Yes the wire needs the positive voltage at one end and ground on the other.
Muscle wire? That is amazing stuff! First time I ever heard of it, googled and read some. VERY interesting an amazing.
Thanks for that tidbit of info.
Ken H>
Keep in mind the requirements of the wire. You said you have .5mm wire. That works out to be about .02 inches. Well its .0196 but you can round that up so we can find its closest cousin on the chart. Which means you'll need a power source that can offer at least 4A. You'll want 6A or more so you don't blow the supply trying to move the wire. And thats only across 1" of the wire. This also means the wire will get pretty hot. There is a chance you can burn out the wire if you leave it on too long.
Now if you use a 5V or 6V power source you pretty much won't need a resistor on it if you use more then 1". With 6V and 1 inch of wire it only needs a 1.34 OHM resistor. Subtract .16 Ohms from that for each additional inch.
This is just my understanding of it. Like Ken this is pretty new to me too. I've heard of it for the first time a few years ago on a PBS show but never really looked into it till now.
KenH:
You want something even more amazing - look up "Electroactive Polymers" (EAP). Ah, heck, here's the wiki article:
It's probably the closest technology we have to artificial muscles.
WOW!!! Brave New World here we come! Many exciting new things happening every day. I'm just proud to live in times where so much is going on... well, the good stuff anyway. Bad stuff is as old as time.
Thanks for the link crOsh.
Ken H>
so if i want to keep the current in the wire for a longer period of time, it'll basically burn out?
and what material is this ?
Yes there is a risk of burning it out. No idea what the material is. Look up Memory metal and see what different types there are and there tolerances.
WOW!!! Brave New World here we come! Many exciting new things happening every day. I'm just proud to live in times where so much is going on... well, the good stuff anyway. Bad stuff is as old as time.
Thanks for the link crOsh.
You're welcome (I would love to homebrew my own electroactive polymer; that, and my own polymer electrolyte membrane (PEM) for a homebrew fuel cell).
Seeing things like this, coupled with the "bad stuff", makes me believe that everyday we live in a sci-fi dystopia; my only beef with this is that we don't flying cars (outside of Moller), sex robots (outside of RealDoll, the jp doll hobby, and that thing a Bell Labs researcher recently created), and off-world colonies.
Then again, we have electroactive polymers, large synthetic diamonds, weird discoveries of super-cooled water, the Arduino, Contraptor, and Fritzing to keep us happy, I suppose!
What is the length of muscle wire you are going to be using?
diameter is .02
length is a few inches 5-6 inches long
one more question....can i put some kind of analogue switch along with the battery thats attached to the mucle wire?????? any particular switch in mind?
thanks
You could always use a pot instead of a resistor and see what you can get from the wire as you increase and decrease the voltage threw the pot.