iiButtonButton

Under the guidance of

Mrs. Shobha. K

Mrs. Padmavathi

Presented by

HARI.V

1SG06EC026

DEFINITION:• The iiButtonButton is an electronic chip.

• It is armored in a 16mm stainless steel can.

• Digital circuits that ‘talk’ directly to other chips.

• Long and short pulses encode 1’s and 0’s.

• Every iiButtonButton produced has a unique serial number - no two

iiButtonsButtons will ever have the same number.

• It is durable enough for a person to wear everyday on an

accessory like a ring, key chains,

wallet, watch, metal card or badge.

SILICON MEDIA:• Human-readable labels vs computer-readable

labels.

• Evolution of barcodes and large databases.

• Silicon media as labels that act as standalone

database.

• Can be attached to an object or carried by a person.

• Access to secure areas, health care records,

tracking of items, etc.

Identification by touch:

• To reduce cost, extend the internal connections out to form

electrical contacts.

• Two-piece stainless steel can called MicrocanTM.

• The side makes a ground connection and face makes a data

connection for a simple, self aligning contact.

• 16mm button shape serves all iiButtonsButtons..

• Button Shape is Self-Aligning with

Cup-Shaped Probes.

Technology:• No internal power source required.

• Energy is ‘stolen’ from the data line called parasitic power.

• Needs connection to reader for power and data transfer.

• A signaling protocol that can communicate bidirectionally over two

wires.

• Electrical interface reduced to a minimum.

• Transmission of information via

the same connection.

• The data line is designed as

an open drain output.

Chip built using CMOS technology for low static power consumption.

iButton probe

• Requires momentary touch against a ‘two-contact’ metal probe.

• Information is transferred between iButton and a probe.

• Two communication modes:– Standard mode at 16 kbps.– Overdrive mode at 142 kbps.

• Reads an iButton in less than 10 ms.

• iButton readers come with various upload capabilities from direct PC upload cradle to Palm upload to direct Internet upload cradles.

EXAMPLE OF A PROBE

Memory iButton devices:• Minimum of 1 PC/master required.• iButton Recorder – penshaped mobile

reader/writer.• iButton Editor – hand-held computer that has

additional keyboard.• Touch transporter – large capacity memory

iButton.• Archive computer – keeps inventory of all

objects carrying iButtons.

Memory iButton devices (continued) :

Protocol:• 1-Wire protocol is used.• Half-duplex data transfer.• Discretely defined time slots that are

independent of each other.• Command word sent to iButton slave from the

master.• Serial communication, starting with LSB.

Synchronization:• Master and slave to be synchronised for data

transfer.

• Presence pulse - to indicate to the master the iButton is ready.

• Reset pulse - given by the master requesting for a presence pulse.

Data transfer:

• Command sent to slave – 1 and 0 timeslots.

• Data is read from the iButton using same rules.

• Master defines the beginning of timeslot by a write-

one time-slot.

• To transfer

– Logic 1, iButton makes no change.

– Logic 0, holds data line low.

1) Barcodes:

– Necessity of electromechanical printers

and electro-optical printers.

– Scanning speed, scanning angle, poor contrast or

dirt affect the process.

– Sunlight or other ambient light affects the read rate.

– Decoding is necessary as light must be converted to

electrical energy.

Alternative identification technologies:

2) Magnetic stripes:– Usage of analog signals.– The stripes can be damaged by a brief

contact to other magnets.– Strong fields can erase or damage data.– Any dirt will damage the coil and the reader if

present during the swipe– Precise alignment of card and smooth

movement necessary.

Alternative identification technologies:

3) Chip-cards:

– Not designed for high resistance intermittent contacts.

– Sensitive to alignment and sequence of contacts.

– For economic reasons copper is used, which forms

oxide layer.

– Card malfunction and mechanical bending.

– Unsuited for labeling.

– Limited lifetime.

Alternative identification technologies:

4) RF Tags:– Energy consumption is quite high.– Prone to interference from other transmitters.– Availability of frequencies and allotment to

various applications.– Electromagnetic waves affect human bodies.– Comparatively larger in size.

Alternative identification technologies:

Other advantages

• Computer interface is built into the chip.

• Clam-shell steel container, the Microcan is suitable for

harsh environments.

• Programming using the same probe that reads it.

• Smaller, lighter and less expensive.

• Virtually no energy is needed to read information.

• Reading/writing needs only a single I/O line of the

computer.

Applications

• Care Giver Services in Australia • To measure temperature (for food storage and transport)• Electronic ID (for physical access to buildings)• Store e-cash (for purchases both in stores

and via the web).• Digital Fleet Fueling at

Ryder systems Inc.• Mass Transit in Istanbul, Turkey • Parking Meters in Brazil

References:1) www.maxim-ic.com › Products › iButton › Overview

2) www.maxim-ic.com/products/ibutton/applications/

3) www.wikipedia.org

4) whatis.techtarget.com

5) www.ibuttonlink.com

6) http://www.lothar.com/tech/iButtons/

7) http://www.dalsemi.com