When I was a kid, my friends and I would travel to the town dump to salvage computers and other electronic devices to pull to bits. It was great fun, we would spend days disassembling the devices, pulling out any loose buttons, switches or LED's and construct simple little circuits. Those days formed the basis of all my knowledge of circuitry, or how to successfully create a LED light with a switch. So when it came to putting together the only piece of circuitry for this project (the IR LED array for the head tracking), I figured it would be simple, a little reminder of the days spent at the tip, considering it literally is a LED with a switch.
I was wrong. So wrong.
I looked at this schematic and assessed what I was dealing with. Three infrared LED's, three 22 ohm resistors, a bunch of cabling/wires and 2 AA batteries. What I thought I knew about electricity was one, it travels the path of least resistance (hey! much like my own motivation!) and two red generally means positive while black is negative. This is all good and well but, I'm not an electrician, and now it's time I identify my self as completely electronically illiterate: besides the symbols, this schematic makes no sense to me at all. I tried over and over again visualising what this circuit would physically look like and how I would lay it out on the desk in front of me, referring to a close friend (who actually is studying to be an electrician) for help to no avail. No matter how detailed his pages of notes were, his semi-internet lectures were flying over my head.
I eventually visualised the circuit by physically laying resistors and LED's out on a piece of paper. I have to say, it was a pretty uncomfortable realisation not actually knowing a lot about something that I thought I was pretty easy. Here's a highly professional and detailed rendition of the circuit: