By: Mehdi Dibaji
Last Revised: April, 06, 2007
As electronic devices are becoming smaller everyday we are wearing more of our personal information on our bodies.
For example, cell phones, PDAs, pocket gaming devices, music players, and etc. We have been able to connect our
that uses the human body as a medium to send data across various devices using a near electric field.
Figure 1. PAN
Like every other network communication one requires a PAN transmitter and PAN receiver (both battery powered). The PAN
transmitter capacitatively couples a small displacement current through the human body to a receiver . The transmitter doesn’t have
to be touching the human skin. A capacitor is a device for accumulating and holding a charge of electricity, consisting of two equally charged
conducting surfaces having opposite signs and separated by a dielectric. Whenever, there is a current in a circuit and there is a capacitor
a displacement current occurs. This current is transferred from the PAN device to the body. In a PAN, the transmitter electrode facing the
body and the skin act as a capacitor. By adjusting the electric current, the current between the transmitter and the body can be modulated.
As a result, data can be transferred across to the receiver (by means of current flowing through the body, which also interacts with the body in the same way).
Watches, pagers, phones, credit card, and even your own shoe can be a PAN device. The advantages of PAN technology is becoming more
clear now in that it removes IO and storage capacities. The watch can be the monitor, the PDA can be a storage device, and the phone can be your
connection to the outside world.
A prototype has been developed to show the digital exchange of data through a human body using battery-powered low-cost electronic circuitry.
The detector synchronously integrates the tiny received displacement current (e.g., 50 picoamperes, 330 KHz) into a voltage that can be measured by a
slow, low-resolution analog-to-digital converter (50 KHz, 8 bits) provided by the microcontroller. The PAN transceiver uses five "off-the-shelf" components
costing less than $10 in large volumes. Ultimately the analog components and microcontroller can be combined into a single CMOS (complementary metal-oxide semiconductor)
integrated circuit to produce a low-cost integrated PAN transceiver.
Figure 2. Prototype
When it comes to personal information and data security is always an issue. Communicating with devices has more and more simple over the past few years; therefore,
imagine if you bump into someone or shake someone’s hand you will be exchanging information. Thus, there needs to be a lot of encryption.
PAN technology should not be very big in size so the battery, processing unit, and other hardware should come as a single unit.
IBM sees PAN technology being applied initially in three ways: