Position Detection and Identification of Products using RFID Technology

Master ThesisChristian Decker

Supervisor: Michael Beigl

This thesis representation was held at TecO on September 20th 2002http://www.teco.edu/~cdecker/pub/publications.html

Structure Problem + Today‘s Situation Goal SmartShelf Technology Prototypes Conclusion

Problem

quantity+type ofproducts (purchase)

quantity+type ofproducts (sale)

Scenario: traditional retail business

Quantity of products on shelfes (Out-of-Stock problem)

History of products Success of product placement

???

Today‘s Situation Refill of shelfes happens at fixed points in

time – not driven by necessity Product placement

rearrangement of products in stores to stimulate the consumer‘s buying behavior (Surprise-Effect)

test of sales combinations of similiar products (trial-and-error)

There is no quantitative proposition about theinteractions of the consumer!

Goal: Interaction Detection System

Consumer buying behavior remove, add, move (basic interaction

patterns) Improvement of existing systems

automatic re-order systems statistics

Provide new services recommender-, broker-, help desk-systems electronic pricing

SmartShelf – ID Technology Identification and position detection of

products using RFID insensitive to dirt, wetness etc., tiny,

contactless, no internal power supply products equipped with transponders (price!)

H400x EM Marin 125kHz not collision aware 130ms read cycle 40bit ID,read-only

SmartShelf – Design Identification

every transponder has its own unique ID Position detection – 3 reading units in parallel

big detection surface divided into smaller RFID detection spots (here: only 1 transponder per spot)

SmartShelf – Antennas Requirements

local detection through “limited” reading field homogenous reading field big detection surface with only a few antennas

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Distance from Antenna's Center [mm]

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4-Coil-Antenna

SmartShelf – Function Detection – Gathering –

Communication

SmartShelf – Sychronisation Synchronisation of communication

serial communication, TTL, fixed length of data among the reading units: start of

communication is determined via signals (READY,Request(RQ) )

to external systems: CTS signal and Command/Response

Sychronisation of antenna activation fixed schema for activation of antennas

avoids reading collisions of adjacent detection spots avoids simultaneous activation of two antennas on

the same reading unit

SmartShelf – Synchronisation 2

Timing synchronisation max. time for activation+reading of an antenna is

taken to determine the start of the next step in the program’s execution

Address sychronisation central unit addresses an antenna for reading,

sets up the time pattern for all Barrier synchronisation

all reading units work independently until a sync point – program blocks there!

global signal to continue the program’s execution

SmartShelf – Software Memory function

problem: assignment of transponders is not stable

assumption: detected transponders do not disappear suddenly

if apparently disappeared, then several read trials increases stability, but needs time

Fast Update transmission of data starts even if not all

antennas were checked again for transponders disadvantage: part of the informationen is out of

date

SmartShelf – Prototypes 1st Prototype:

built completely by hand address sychronisation error-prone hardware, instable software, slow

2nd Prototype: PCB, optimization of antenna’s characteristic barrier synchronisation, memory function, fast update hardware reliable, fast, 99.7% detection reliability

3rd Prototype: spike filter tweaking of parameters without reprogramming fast, automatic tweak control

Conclusion Identification+position detection (99.7%

reliable) Basic interaction patterns (remove, add und

move) can be detected – consumer behavior can be acquired quantitativly

Detection speed too low – Goal: realtime detection of interaction patterns

Standard interface allows integration in existing systems and development of new applications (recommender and broker systems)