EMBEDDED RFID IN PRODUCT
IDENTIFICATION
Tommi Kallonen
Jari Porras
Lappeenranta University of Technology
Contents
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Motivation
RFID technology
Embedding RFID tags
Identifying concrete elements with RFID
Test results
Conclusions
Motivation
Automatic identification can help us follow a single product
during it’s lifecycle
– Maintenance
– Analyzing error situations
RFID-tags can be used to automatically identify individual
products – not just product groups
RFID technology doesn't need line of sight
– Tag can be hidden
– Hidden tags can remain inside a product through it's lifecycle
RFID technology
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Automatic identification using radio waves
A tag holds the data and a reader accesses that data
Tags are cheap (cents – few euros)
Tag doesn’t need a power source
Often used in logistics as a replacement for barcodes
Classifying RFID tags
Power source:
– Active tag
– passive tag
Operating frequency
– Low Frequency (~130kHz)
– High Frequency (13.56 MHz)
– Ultra High Frequency (~900MHz)
– …
Functionalities:
– Read only
– read/write
– advanced tags (encryption, access rights…)
High Frequency vs. Ultra High Frequency
HF (13.56 MHz) and UHF (~900MHz)
tags have different operating
principle:
• HF – data is transferred with
alternating magnetic field
(transformer)
• UHF – data is transferred with
electromagnetic waves
Embedding HF and UHF tags
HF
• Short read ranges (usually less than 1 m)
• Environment doesn't have a big effect. Only metal prevents
reading
UHF
• Longer read ranges (up to several meters)
• Signal weakens a lot when travelling through different
materials (signal doesn’t travel through water)
• Detuning if near metal, liquids..
The project – identifying concrete elements
The goal was to use RFID tags to identify
concrete elements through their life-cycle
Currently elements are identified with a label:
• The label doesn't differentiate identical
elements (they all have the same code)
• The label can get lost during production
• The label is certainly removed after
installation
The project – identifying concrete elements
•Tag is placed inside pre-cast
construction element during
manufacturing
•Reading the tag needs to work
under different circumstances
– Humidity changes
– Temperature changes
– Element can be covered
with snow or ice
Tests – preliminary tests
- In preliminary tests we tested different RFID
technologies available in the market to identify
concrete elements.
- HF technology proved to be more reliable than
UHF and there were more handheld HF readers
available.
=>HF tags based on ISO 15693 standard were
chosen for following tests along with
USB/Bluetooth enabled handheld reader
Laboratory tests
Tags were embedded in different materials and
successful read distances were measured
Reading proved to be reliable through concrete,
water and ice – only metal prenented reading
Size of the tag makes a big difference
Practical tests
Practical tests
•29 tags were inserted into pre-cast concrete
elements
•Elements were of three different types:
– Wall which consists of two layers of
concrete and a layer of insulation in
between
– Balcony floor, single layer of concrete
– Balcony wall, single layer of concrete
•Tags were placed on standard location
– They could not be seen on the finished
element
Test system
• Test system consists of a RFID tag, a reader, a
laptop and a server with a database and WWW
server for user interface
Tag placement
Placement of tags was problematic
– Some tags were placed on
locations where they could not
be read in completed building
– Since elements with RFID tags
were not marked, we could not
know which elements had tags
(if many similar elements
existed and only few of them
were tagged)
Results of practical tests
• Reading worked well with wall elements, 15/18
were found and 3 not tested
• Two tags where not found – they where probably in
different building and therefore not tested
• There were no certain failures with reading
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Conclusions
Technology works, but there are still practical issues
– Placement of the tags. Tags need to be found
easily when necessary, but they may not be
visible in finished product
– Installing a tag needs to be easy and simple
– Follow-up actions are needed. Tags can be
found but what after that?