[Kyle Fredericks] tipped us about his first electronics project, a cheap and smart sleep mask that uses a vibration sensor to detect rapid eye movements.
As some of you may know, REM sleep is the part where you dream the most vividly and actively. If some external stimulation (sound, movement) is sent to you at this moment, it may help you take control of your dream by becoming aware of it. If not, your brain will create dream scenarios that incorporate this stimulus.
The interesting part of the concept is that the vibration sensor calibrates itself at the stage 2 sleep, when no eye movement occurs. This later allows a very accurate detection of the REM sleep stage, triggering a shelf stereo. Secondary buttons are even included in the mask sides.
[Kyle Fredericks] went to great lengths to document every step of the project, making it a perfect first step to learn electronics for beginners out there.