Sleep Detector Power Saver

I remember umpteen instances when I've seen people leave their lights and/or televisions turned on and fall asleep. While the person is recharging himself his appliances are continuously hogging power all night for no useful purpose at all. Of course the easiest solution to the problem is for people to realize the mistake and be responsible enough to turn off all unwanted utilities when they go to sleep.

But since we still have so many careless people around, there is a potentially huge market for a product that could detect sleep in a person and take action accordingly - switch off lights, TV etc. Sleep detection could be done based on monitoring of one or more of various parameters - heart rate or pulse rate, body movement, body temperature, respiration rate etc. The major challenge in such a product would probably be to identify which among these myriad options would provide the cheapest and the most reliable way to detect sleep. Any answers?

[This post is an elaboration of Problem-3 on the post "Nine Problems Worth Solving"]

Jerky Ride Writing Assistant

Travelling by bus, train or car can be tedious if the journey is long and more so if you are all alone. Many resort to reading in order to pass time. There are times when I felt like writing something when traveling. But because of the jerky nature of the ride, it becomes rather difficult to write anything legibly. It's at times like these that I've often wondered if there could be some device that could be strapped on to my wrist, which would allow me to write normally the way I would in a stationary and jerk-free scenario. It could probably compensate for the jerks by applying precise forces (of the right magnitude and direction) on the hand - some sort of an active noise cancellation!

Another possible solution to the problem is to have some sort of a damper or a shock-absorber structure that keeps my hand and the notebook steady irrespective of vibrations in the vehicle. Any thoughts and/or suggestions from the reader are most welcome.

[This post is an elaboration of Problem-2 on the post "Nine Problems Worth Solving"]