How to create cheap light-up 8x8" squares?

November 21, 2006 7:03 PM

My daughter is doing a science fair project and we need a bunch (like 500) of illuminated 8x8" squares. These can be made out of anything -- paper, plastic, whatever -- but they need to be battery-operated. We're hoping to spend about $1.00 per square. Any ideas?

For instance, one idea is to take a mini-keychain flashlight and put it in a clear or frosted plastic sleeve (like the kind you'd buy at Staples for filing reports).

The depth of the square does not matter. They can be flat or several inches high. They just need to be somewhere around 8x8".

We'd prefer to use off-the-shelf pieces that the kids could assemble, rather than soldering LEDs or anything like that.

Any help you can give would be appreciated.

posted by phonepimpster to technology (15 comments total)

Does the plastic have to be flexible or rigid?

Is the plastic being mounted in something else?

Does the plastic have to be clear / white-semitransparent or are colors OK?
posted by brain cloud at 7:17 PM on November 21, 2006

$500 dollars for a science fair project, or am I misunderstanding?
posted by odinsdream at 7:33 PM on November 21, 2006 [1 favorite]

Hmm. Upon reflection & searching lots of plastic options, using plastic does not seem like the economical way to go. It would also be a lot harder to cut even if it were the thin report-cover style plastic -- in order to fit your price constraint, you'd have to buy very large plastic sheets and cut them to the desired size. Not fun!

So that leaves paper, for which I'd recommend ordinary waxed paper because it's quite cheap, easy to cut, and would let light through well.

With respect to the lights -- does each light have to have its own source of power (battery)? If not -- ordinary christmas tree fairy lights would be small enough, cheap enough, and not requiring lots of power.
posted by brain cloud at 7:43 PM on November 21, 2006

I agree, unless you can find some surplus plastic squares (which is possible), I'd go with some thin almost translucent paper from a craft store, stapled to a wooden frame.

For lights, your LED flashlight idea is a good one. Search for "led mini flashlight lots" to find a single auction for a lot. You can get it down to ~$1 per light.

To power them, get a small 3V DC power supply wall wart and wire it to all the lights.

Getting the total cost close to $1 per square is just almost possible, but I think you're going to go over. To get cheaper you'll need to solder some LEDs. :)
posted by todbot at 7:57 PM on November 21, 2006

I know you said battery operated, but around Halloween sometimes I see paper bags with small candles inside them, as sort of road markers. (I think they put kitty litter inside to keep them from blowing around) Those might be about 8x8, and really easy to get.

Along the lines of the LEDs todbot mentioned, maybe you can make LED throwies and put them into some kind of 8x8 enclosure? They look like a good project for kids.
posted by Brian James at 8:25 PM on November 21, 2006

Or buy strings of LED Christmas lights, if having them connected is okay. I just bought two sets of 20 lights each at Walgreens, they were $5 for each set and they're battery powered. I'm sure at this time of year you could find a similar deal. They come in either multicolored or plain white, and you can have them either blink or not blink.
posted by cali at 8:44 PM on November 21, 2006

10-packs of white LED keychain lights are $5.99 at surpluscomputers.com. $0.60 each, but they lack switches. you'd need to rig something to keep them on/squeezed all the time. Maybe binder clips? They're free if you steal 'em from work!
posted by xiojason at 8:57 PM on November 21, 2006

And don't forget FlashyBlinkyLights.com!
It's a fun site just to visit, let alone buy anything.

They were the ones I was thinking about, like here's some cheap mini led flashlights.
posted by todbot at 10:43 PM on November 21, 2006

To power them, get a small 3V DC power supply wall wart and wire it to all the lights.

There's no way a single "small" wall brick will produce enough current to power 500 LEDs.
posted by Steven C. Den Beste at 12:03 AM on November 22, 2006

Yeah your right. A switching 2A supply would power about 100 lights (2000 mA / 20 mA/LED). So you'd need five of those.
posted by todbot at 1:01 AM on November 22, 2006

Oh and you can get 5V 2A switching power supply wall warts for about $6 off ebay.
posted by todbot at 1:03 AM on November 22, 2006

Getting the panels themselves will present a problem in terms of cost and time.

What do you want the lighting to look like? If you put an LED/lamp behind a presentation sleeve, you'll get a bright spot and not much else. You could get a sheets of plexi and craze them and light them from the edge to getting more even lighting.

500 8"x8"? Let's say you get a 4'x8' sheet of .060 plexi, which runs about $50. That'll give you 6x12=72 8"x8" squares at 100% yield if you have a good score-and-snap rig. Cost? $350.
Then you'd have to craze the surface (buffing with coarse sandpaper). If you allow 3 minutes of work per square, that's going to be close to 25 hours of continuous work. Let's say that your daughter can manage an hour a day and 3 per weekend day, she'll just be working on these squares for close to more than 2 weeks.

Although it won't meet your size requirements, you can get 250 sheets of 2.75"x1.25" EL sheets for 0.19 each. You'll need to solder, but the cost is pretty dang cheap per unit area.

What the heck is she doing anyway where she needs 375 square feet of light?
posted by plinth at 6:31 AM on November 22, 2006

Maybe you could employ a big mirror and get away with only 250 lights?
posted by rongorongo at 6:47 AM on November 22, 2006

How about something like this?
posted by Monkey0nCrack at 9:15 AM on November 22, 2006

Or light by this?
posted by Monkey0nCrack at 9:16 AM on November 22, 2006