Netflix do a remarkably good job at explaining how the project works, and how it can be realized. Apart from the electronics stuff that’s all a-b-c to Elektor readers, there’s a fine section on selecting the sock design and actually knitting the garment, so get your daughters and girlfriends involved!
The sleep detection system is based on actigraphy: an accelerometer detects when you’ve stopped moving for a prolonged period of time and triggers a signal to your TV that pauses Netflix. When it detects that you’ve dozed off, an LED light in the cuff of the sock flashes red, warning that the pause signal is about to be sent to your TV. Any motion will stop it from firing.
The Arduino Pro Trinket is employed for its small form factor, ease of use and onboard USB. Plus it has plenty of I/O pins for playing around with advanced features. You can also use something like a LilyPad, though it will change some component requirements.
When you fall asleep, your sock will need to send either a “stop” or “pause” command to the TV, or exercise control over the power button. That can be done by patching and tweaking the little Sketch supplied by Netflix to get you going. More extensions are possible: if you like watching Netflix from behind a coffee table or cocooning under blankets, your socks may not always have a clear line-of-sight to the TV. An easy way to handle this is to build a simple IR-emitting base station, using something like a Bluetooth or 2.4 GHz transceiver to communicate with your sock and send IR signals right to your TV.
I’m sure that building the project is less likely to make you fall asleep than watching some of the programs on Netflix.