3 ms·
Another option is that they use a capacitive sensor, which reminds me of the smart pill bottles being developed by AdhereTech and others (http://www.theverge.co
by character0 12y ago
Another option is that they use a capacitive sensor, which reminds me of the smart pill bottles being developed by AdhereTech and others (http://www.theverge.com/2014/1/8/5289022/adheretech-smart-pill-bottle http://www.theverge.com/2014/1/8/5289022/adheretech-smart-pi...).
Although, I think this is less likely- I like your guess better.