Cool project! Reminds me of the stupid “meters” that Duracell used to have on their batteries.
It was just a strip of plastic with foil underneath, probably the same kind used in those “mood rings”. You’d press on two parts of the battery, the foil heats up, and the plastic changes color depending on how much capacity the battery has left.

They’re not made that way any more for obvious fire hazard reasons, but the same method could be used for this project without having to put so much current through it.

Google for “Duracell PowerCheck”

REALLY cool. true hack =)

it might be interesting to optimize the on/off times. I’m thinking adding a heatsink and increasing the pulse power will make the on and off times shorter?

If the off time is about a minute, I bet it would make a really cool clock. Every minute it would heat up to display the current time, and it should fade enough for the next refresh

I’d use it to make one of those water traps from Dune, where the changing colour of the trap reflects or emits radiation to promote condensation. Then I could start a career as a water farmer.

Put a peltier device on the back of it so you can cool it down quicker ?

That has to be the most energy wasteful 7-segment display ever! I like it :)

And if you made the clock with an analog face, you’d get a nifty fade effect as the “dials” moved. Besides art stuff though, I can’t think of anything useful.

Well, peltiers are the obvious solution so don’t be surprised if it gets mentioned several times. This needs to be put into a translucent housing so we have colors instead of just black and white. For frequent changes it’s wasteful, but if you only change it every minute it comes down to an average of 50mA (what’s the voltage?)

Amperage is useless here without resistance. Watt Hours would specify how much energy it actually takes to change the color.

The only flaw I can really think of (for the sake of being critical) is that a major reason you would want to deploy paint like this instead of a display is in a situation where you have it exposed to the elements like on your house or a wall or something, but the major flaw is that if it’s during winter then it would take quite a while to change the display / it might not change at all, and during very hot conditions it might prematurely illuminate…

…but I love where this is going – I’d like to do something like this with heat sinks to indicate critical temperatures or something. Very cool.

how expensive is this paint, and where can one get it?

living in Chicago, solar powered roof paint – white in summer for cool reflection, black in winter for heating up.

heres some more cool paint by the same company, im assuming. its soft feeling paint

http://alsacorp.com/products/softtouch/softtouch.htm#productinfo

id love to paint my car black with this stuff

also, they carry blue to white color changing paint

Little off topic……Man the flashpoint on that soft touch stuff is low.__________ Cred to guys who posted it first… First thing I though of was clock. Like Matt’s analogue idea. Projector paint sounds kool.

I’d paint my car, and use it to rob places when it’s black, then change to white so the fuzz dont find me…

You clould probably incorporate this with those other multi colored paints, and different glosses and top coats to get a whole range of colors.

Nifty! A clock would be kinda neat. Everyone makes clocks, kind of like reminding us how our time is limited, and we should make as much of it as we can…

Although I usually detest personal attacks, I have this to offer:
@googfan:
A) “the minutes only change… one time a minute” — I don’t know what you’re getting at here, but I’m pretty sure most digital clocks work exactly like that…
B) As you can see, the majority of comments actually attempt to make some sort of rational sense, and they spell words out. Thus, you are the odd one out, and as you so aptly put it “get off de internet. think b4 u speak.[sic]”
C) Please, bury your computer… You can even get someone to take pictures of its funeral and post them on Flickr or something. Heck, I’ll PERSONALLY submit THAT as a hack.