BBC News 
August 9, 2013
How do you make sure your elderly and forgetful mum is taking her medication regularly?
According to Proteus, by having that tablet text or even tweet you when it hits the stomach.
This isn’t science fiction – although the company appropriately enough shares its name with the Proteus, the microscopic vessel that boldly went where none of us have gone before – inside the human body – in the cult 1960s movie Fantastic Voyage .
The key is a tiny ingestible sensor that can be embedded in a tablet. It works like a potato battery.
“If you stick a bit of copper and a bit of magnesium in a potato and you wire it up you can power a lightbulb. It’s a simple bit of chemistry that says two dissimilar metals in an ionic solution create an electrical charge,” says Mr Thomson.