EMBEDDED RFID IN PRODUCT IDENTIFICATION Tommi Kallonen Jari

EMBEDDED RFID IN PRODUCT IDENTIFICATION Tommi Kallonen Jari Porras Lappeenranta University of Technology

Contents • • • 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 • • • 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 (~130 k. Hz) – High Frequency (13. 56 MHz) – Ultra High Frequency (~900 MHz) – … Functionalities: – Read only – read/write – advanced tags (encryption, access rights…)

High Frequency vs. Ultra High Frequency HF (13. 56 MHz) and UHF (~900 MHz) 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

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?