Rube goldberg project...

[Salik Syed]

okay so for our physics class we have to make a project which completes a simple task (this year its to cut paper) in a complex way (ever heard of rube goldberg....? google him!)
we get extrapoints for different energy transformations (i.e heat-->mechanical, chemical--->light electrical--->light) and we get extra points if the machine is resettable within 15 seconds.
we've figured out how to do everything except heat, and still make it resettable. we drop a coin which connects a light bulb, then
Basically we wired a photosensor--->transistor --->vinegar battery---> another transistor---> another lightbulb
the vinegar battery counts as chemical, the light triggers the photo sensor (light---> electrical) which allows current to flow through the vinegar battery through the transistor which relays power to the next light, this step is repeated 6 times (one lightbulb turns on the next photoresistor which turns on the next bulb which turns on the next photo resisotr etc. etc..) , the maximum number of each energy transformation is 6 so... of course to maximmize bonus points we do it 6 times.
mechanical is very easy (use motors or something) but we are boggled about how to make use heat to triggers something and still have it resettable so everything works the next time through.
any ideas?

[Brandon Martus]

This may not be resettable in 15 seconds, but ..

http://www.chiefdelphi.com/forums/sh...ad.php?t=46503

[Salik Syed]

anyone have experience with circuitry and stuff
i don't know if this would work but i was thinking of wiring an NPC Thermoresistor into a NOT logic gate, then wrapping the resistor in a heating element, so when there is heat the resistor will increase its resistance and not allow current through.
my question is will these types of resistors lower the current enough to trip a logic gate?\


OR does anyone know where to buy Bi-metal strips?

[nehalita]

I did one last year to change the batteries of a flashlight and have it turn on. I still have pictures of it actually (i think...).

As far as using heat, do you have a time limit for all of this to happen? If not, you could try melting ice to do something... ice is easily replaceable.
So if you have a net of some type with ice in it, and you melt the ice, the water can go through and add weight to a certain bucket that can then trigger another step. You can melt the ice by turning on a blow dryer or whatever else you might want to do.

hope it at least switches on a light bulb for you...

[Not2B]

Originally Posted by Salik Syed

OR does anyone know where to buy Bi-metal strips?

Get an old toaster, and grab the bi-metal strip out of that. Of course, that might be asking you to heat up your device too much - not sure if you are allowed to use that much electrical power. Set it up at the beginning, and have it auto shut off after it trips. That should let it cool off enough for the next round.

Heck... can you just USE a toaster?

[Salik Syed]

well we don't have enough time to melt ice, and the thing is we are running 6 volt lantern batteries so it's not exactly enough to cause a lot of heat...

[Alekat]

I'm partners with Salik on the same project.
Just had an out-of-the-box thought. If instead we cooled something down to activate a trigger, it would still be considered a heat transformation right? However, i'm having trouble going anywhere with this idea. So i'm handing off the torch (no pun intended) to anyone with some ideas.