As part of his "useless alarmed Coke can project", Instructables user 'giuliom_95' has created a simple yet interesting sensor with a can of Coke. In effect it has been converted into a simple capacitive sensor, as the project can detect when a person places their hand near the can (in order to activate his alarm) and then sounds an alarm at a particular threshold. The circuit seems a little obscure but is claimed to work.
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