Microsoft patents human circuit

Microsoft has patented a network that uses the "body of a living creature" as a data bus and power supply for communication between two electronic devices. (U.S. Patent 6,754,472).

According to the abstract,

Methods and apparatus for distributing power and data to devices coupled to the human body are described. The human body is used as a conductive medium, e.g., a bus, over which power and/or data is distributed.

The patent includes the use of pulsed AC or DC to power miniature wearable devices.

100 Hz signal may be used to power a first device while a 150 Hz signal may be used to power a second device. Digital data and/or other information signals, e.g., audio signals, can be modulated on the power signal using frequency and/or amplitude modulation techniques.

For instance, a miniature speaker may be located within an earring while an audio input microphone may be attached to a bracelet.

(The drawing is from the face of the patent).