Air Temp Nitinol

[Paul-R]

hello Paul-R . the Volts will drop but the current is still there.

The snag is that many devices need a constant voltage. Is there a circuit that one could
hang off it to supply a steady voltage as the power is drawn?

[Cherryman]

The snag is that many devices need a constant voltage. Is there a circuit that one could
hang off it to supply a steady voltage as the power is drawn?

I've heard that a lot of those hand powered (crank, shake etc ) flash lights use capacitors instead of batteries, so you might want to look in those circuits. As they also need a slow discharge.


example:



http://www.modernoutpost.com/shop/flashlights/335-lightstorm-cl1.html

[gadgetmall]

The snag is that many devices need a constant voltage. Is there a circuit that one could
hang off it to supply a steady voltage as the power is drawn?

Hi . paul . sure there is solid state regulators that can do that . I have build a few for lasers because the need 4.5 volts . Most every circuit i have designed or replicated is 1.5 - 1.2 volts  They run constant down to less than .3 volts so the Bcaps serve me well with just a pot in series . My point was they can Anneal Nitinol Wires in a controlled way because the resistance in that wire is almost as high as nichrome wire. takes a lot of current to heat them up properly and evenly . You can't do that with a torch and an oven is only good for shaping the Niti. you can shape it in an oven but the phase change will be wide .I need very narrow for Air temp Phases .

[Tom Booth]

Thanks for the info on the capacitors, I wasn't aware of these advances.

I'm actually 100% off the grid using photovoltaic panels and  replacing worn out deep-cycle batteries every so many years has been something of a nuisance and expense.

Getting back to the hot and cold thing. I thought of one possible explanation.

Perhaps when bent, the Nitinol takes on a characteristic something like aluminum. That is, it becomes a heat "reflector" of sorts, quickly absorbing and releasing ones own body heat when touched. I've sometimes felt what seemed like heat coming off some aluminized insulation but of course it was only reflecting heat from my hand.

When straightened perhaps it becomes more of a heat conductor drawing heat away and so feels cold.

Just a guess. On the other hand you say that this is more than subjective. i.e. causes color changes when a liquid crystal strip thermometer is applied.

At any rate it seems strange that you say heat is felt but not conducted to your hand. I'm not sure what that means really, as the sensation or feeling of heat is (usually) a result of actual heat exchange, except something like a chemical heat, hot pepper sauce or something.

I'm wondering if any extensive research has been done to figure out what exactly is going on, how long does the effect last. (How long does it stay hot after being bent) etc.

If it continues giving off heat for a long time (or seemingly indefinitely) does it then get that much colder when released the longer it has been previously stressed ?

Also I'm wondering if it isn't doing something like conducting heat when bent.

That is, I've only seen this in the video where someone is actually holding and bending the Nitinol with their hands. Theoretically, I suppose the heat could be absorbed at the ends where it is being held in the hand and the heat released at the point where it is bent. That would make it a sort of heat-pump when stressed.

If that were the case it would probably do the same thing even if mechanically bent - absorbing heat from the environment at the unstressed ends and releasing it at the point where stressed. Again that would make it a kind of heat-pump with no moving parts. Even if it were only transporting or conducting heat instead of actually generating heat, that seems incredible enough in itself.

If you (or anyone) know of or come across any additional information/research on this please let me know. It kind of begs some sort of explanation.

[gadgetmall]

there is a nitinol pdf that was on the Internet and can't find it any more. maybe fbi took it out . they seem to want to control the Internet now.

I really think once you feel the power and strength of the work it can do you will understand that that heat cold thing to me interesting but not useful as a motor . loops of this stuff on the  right size pulleys(small) look like the key and lever motors using small pieces straight on a spoke looks promising . It is cooler now and my nitinol is soft outside so i will be testing  a small model out side in a small hole with water bowl insulated from the air  and  brass pulley above ground to test the winter cycle and see if the ground will give me heat instead of cold . if it does give me that 25 30 degree difference the phase change will happen and the flywheel should turn .The flywheel will have magnets on it and capture the field in an air core pickup  and charge a B-cap. Hopefully that b-cap can charge and switch on lights outside .