Managemate is a suppier and developer of RFID systems for the Waste Industry. Through our experience and in house R&D, we have chosen to use Texas Instruments Low Frequency passive RFID tags. Reasons for their use is based on the following:

  • simple design
  • Wide range of operating applications
  • rugged design and long life span
  • ability to cope with harsh working envirnoments
  • ability to be attached to various mounting medium (plastic, metal)

The following Case Study is preseneted to provide information on the ability of the TI RFID to withstand harsh environmental conditions and also its ability to have a long operational lifespan.

Summary of the Survey

Using a test survey of 670 random RFID enabled refuse containers in consumer use for five to fifteen years Texas Instruments was able to read 99%+ of these Texas Instruments low frequency transponders.

This study proves the ruggedness of low frequency technology in this application and the advantages of using Texas Instruments LF transponders. The Texas Instruments transponders also have a patented half duplex technology (HDX) which improves the read range of the tag and provides a high level of good reads during the collection process.

City Description

The City of Edmond, Oklahoma is located just north of Oklahoma City, Oklahoma. The population is approximately seventy five thousand people and twenty eight thousand households. Edmond has a council-manager form of government that was established by charter when Edmond became a city in 1925.

The City of Edmond provides weekly curbside refuse and recycling collection. They also offer several other programs to help households when they need to dispose of household hazardous waste and bulky items.

The utility complex is located in the modern $22M Cross Timbers Municipal complex completed in 2005.

Background

* The city uses Toter refuse containers for automated refuse pick up and have approximately forty four thousand in use today. In 1993 through 2003 they equipped the containers with Texas Instruments low frequency RFID transponders.

The purpose was to anticipate a possible use for service verification and route management. Due to the small geographic area, low landfill costs and the use of small manual pick up recycling containers the business case did not warrant the use of this system. Many other cities with different metrics are embracing RFID systems.

* The city stopped purchasing the containers with transponders in 2003 but the original transponders were not removed from these containers. There are an estimated thirty four thousand containers equipped with the RFID transponders still in use today. The RFID glass 32mm tag was placed in three different plastic holders; the oval and single rivet holder was manufactured by Texas Instruments and the smaller rectangular holder was manufactured by Toter.

* The City uses Peterbilt chassis with Heil fully automated compaction bodies for refuse pick up and collect approximately 1200 containers per route.

* TI has worked in the refuse market for 18 years in Europe and in the US. The advantages of a RFID based system are service verification, asset tracking of containers, incentive based recycling, pay by weight refuse collection and route optimization.

The Study

Texas Instruments wanted to study the long term life expectancy in real time of the RFID transponders on refuse containers.

The City of Edmond provided this opportunity since they have RFID containers in continual use in the field for approximately 5 to 15 years. Since the basic component in a RFID system is the tag itself we believe it is critical that the tag and container function for a minimum of five to ten years.

Factors to consider for a RFID system like this are the environment conditions (rain, snow, heat, freezing cold, dirt, mud and refuse grime), the ruggedness of reader system and integration onto a truck, the number of pickups per week, the handling of the containers by the workers and the automated handling system on the truck. The ruggedness of the tag and the tag technology must withstand these factors and give 99%+ good reads every time the containers are picked up.

The purpose of this study was to collect data by determining the percentage of good reads vs. no reads on a statistical number of these containers. Damaged containers or missing tags were not considered in the survey.

With the help of the cities Solid Waste Supervisor we drove to the city and were given a map of the collection routes for that day. We were also given a grid map and suggestions as to where we should do the test. Considerations were density of containers on the street, ease of reading the transponders and the mix of older vs. newer transponders.

We tested containers in a block and one other adjacent block. We tested only those containers that were placed on the curb for pick up and did not attempt to read any others. We used an ASUS A626 handheld terminal with a Wireless Dynamics low frequency SD card reader ( SDID1212); the software application recorded the unique serial number programmed into the read only tag during the manufacturing process of the tag.

Each refuse container also had a human readable serial number stenciled on the front side. We used this number to reference notes on specific containers. The serial number stenciled on the container indicated the age of the container. The oldest numbers started with the letter ‘N’ through ‘Z’ and then ‘A’.

Results

We read a total of 670 transponders of which 664 (99%) had good reads*. Using the tag serial number we were able to go back to our manufacturing records and estimate the date of manufacture on some of the transponders.

Due to time and facility changes some records were lost and we were not able to set the exact dates of the older transponders. However, we could determine that some were manufactured more than ten years ago. The transponder manufacturing dates therefore range from greater than 1993 to 2004. We do not have accurate information as to when the transponders were riveted onto the containers but we do know that the City started purchasing containers with RFID transponders in 1993.

There were six transponders that we recorded as no read; of these there were five no reads without noticeable damage to the container and one tag that had container damage (deformed plastic) around the tag holder. We believe this damage probably also destroyed the capsule inside the plastic holder.

Renewed efforts in 2007 to use RFID based refuse and recycling systems have been driven by the strong momentum of the ‘Green Movement’ to reduce the amount of material disposed in landfills and increase the amount of recyclable content that can be resold by the municipalities.

A number of form factors are available including a 30mm fully encapsulated round disk offered by Texas Instruments. This tag has a single mounting hole for an Aluminum rivet making for more efficient mounting.

The transponders discussed in this study consisted of glass encapsulated electronics attached to the container with a plastic holder.

Additional considerations of the survey

* Another advantage of low frequency technology is that it will read regardless of the contents of the container. Since some RFID technologies are greatly affected by moisture and metal this should be a consideration when choosing an RFID technology.

There were many differenet containers filled with various types of refuse and these all had good reads. We also believe a container with excessive water content will be unaffected since the LF transponders will read even if submerged under water.

* A strong TI advantage is that throughout the Edmond cart history TI has manufactured hardware that will read both the original 1993 tags and the most recent tags sold. This ongoing, almost perpetual availability of compatible tags and hardware without having to endure upgrade or revision charges enables a customer’s cart and truck systems to grow through the years which is crucial in this business.

* Lifecycle Cost of a cart is another consideration. Carts equipped with TI Tags allow the customer to avoid costly service calls to replace inoperative tags. Cities tell us it cost them about $20 to send a repair person in a truck across a City to do any repair on a cart. At 99%+ durability over 15 years the SERVICE COST per cart in service, for tag replacement (at $20 per visit), would be only $0.20 or $0.0133 per cart, per year. Amazing!

About Texas Instruments RFID Systems Texas Instruments is the world’s largest integrated manufacturer of radio frequency identification (RFID) transponders and reader systems. Capitalizing on its competencies in high-volume semiconductor manufacturing and microelectronics packaging, TI is a visionary leader and at the forefront of establishing new markets and international standards for RFID applications.

Customer Benefits

  • ability to clearly and quickly identify properties
  • identify bins by Waste type and Service type
  • manage and target education campaigns
  • locate and retrieve stolen bins
  • simplfy asset management and audit processes
  • lower unit maintenance cost
  • improve customer service response times
  • improved Utilisation of resources

Contractor Benefits

  • identify bins by Waste type and Service type
  • locate and retrieve stolen bins
  • lower unit maintenance & repair costs
  • ability to operate in harsh working environments
  • Reduces costs by providing a good tracking system
  • simplfy asset management and audit processes