What would you do with these?

[lightbox]

They have 20 IR LEDs each, no battery or enclosure.

[markdi]

You should try to power one of them up

that is what I would do

oh ir led's

that's different

[The_LED_Museum]

Well, I supposed you could turn them back into "Fox Trax" hockey pucks...I believe that's what they were originally [img]/ubbthreads/images/graemlins/wink.gif[/img]
The IR LEDs in them would not be visible without night vision equipment or most digital cameras; swapping them out with red, orange, yellow, or yellow-green LEDs might make them visible to the unaided eye.

What voltage of battery do they need?

[gwbaltzell]

I was trying to figure out what the copper tube was for. My best guess was switch. Then I scrolled the image and saw the silkscreen "S1". Duh!

Can't make out what U3 is but the other chips look like standard 4000 series CMOS and should tolerate a fair range of voltages.

[lightbox]

I don't know what kind of batteries it used but it looks like it may be sized for some number of CR2016 or CR2032 type batteries. The tube activates the puck when it's impacted for some amount of time. I remember hearing that the LEDs are highly overdriven since the whole thing only needed to work an hour or so.

[gwbaltzell]

Pure guess would be 2 CR(something) for 6 volts total. IR LED are typically rated at 50 mA.