I've had a second look at this Wii project, and although it seems to be fine as an experimental circuit, I have a few reservations for the inexperienced builder.

For a start, the schematic shows a 1.5V battery, whilst the presenter is plainly using a 9V duracel. The type of IR led is not specified, nor is there any provision for limiting the current with a resistance of any sort, but given the right led and battery combination it might just be OK.

So far as picking up the signal from the led's, interrupted by your movements...it looks good on paper but it also looks as if it needs much tighter parameters than the video suggests........so--buyer beware!