hi all!
I’m hoping your goodselves can help me. I’m scoutmaster for Rochester troop 31 and we have an annual lanparty coming up in Feb. This year I want to make an electronic badge (just like the big con’s ). My constraint is $20 budget… I can probably squeeze an extra dollar or two, but that would be pushing things…
My thought is this:
I’ll 3d print the base of the badge with the troop name and “LanParty 4” on it as it’s our 4th annual lanparty. Glow in the dark, of course 
I’m thinking about using a PI zero, a 16x9 charlieplexed LED driver board, a blue 9/16 charlieplex LED board, and an IR send/receive daughterboard.
I’d like to have the LED’s have random patterns and whatnot as the default mode. But when the badges get close to another badge, I’d like the LED’s to go into “attraction mode” and have two “Wallie and Eva” type eyes appear. there are girlscouts at or lanparty so if it’s a “female” badge I’d like it to maybe wink or something like that.
From what i see this is all possible, but I have to drive the costs down to under twenty bux per badge… I’ll be making 25 badges…
Any thoughts for cheaper alternatives? Perhaps alternative of the LED and driver board? perhaps an all in one solution? I’m up to about $25 each right now with the IR component 
I dont’ want to have to solder 144 x 25 LED onto boards to save a buck, that would take me weeks… and that’s $25 without the ribbon cable and button cell holders… and without the spool of filament for the 3d printer I really hope I can get cost down, maybe an LCD screen instead of the LED matrix? the LEDs are cool though 
thanks all!
Mike B