I somehow managed to lose my Wii sensor bar. I was surprised to find that none of the shops around here sell replacements, since they are composed of nothing more than some plastic and infrared LEDs. Huge markup potential.No matter! Wii "sensor" bars are easy enough to make with materials I had lying around the house. There are tons of these builds floating around the web but electrically I think mine's one of the more sound ones out there.Most people use resistors to drop the current for LEDs but I've instead used an LM317 variable voltage regulator as a current limiter. It's a common use for the chip and I can see why: the thing works like a horse to keep the current at the desired level.I was surprised that the current didn't divide when I wired the second set of LEDs in parallel; the LM317 compensated to keep me at a cool ~20mA per LED. I opted not to use another LM317 for voltage control since it's more or less impossible to go over 2 volts per LED with this circuit.The LEDs themselves were scavenged from a couple super-cheap IR helicopter controllers. The wiimote seems to love them.I didn't have a battery holder so I used Super Sculpey and chopsticks to make one. In hindsight, it was probably a waste of valuable Super Sculpey, but it works. Behold, the ugliest Wii sensor bar ever created!Awesome! Now we can play some Wii.Edit: Here is the schematic in case anyone's interested. Critique / criticism welcome!