Vizinex, Barcodes Inc. Deliver Specialized RFID Tag for DOT Bridge

Under pressure of a four-week deadline, the companies designed, manufactured and printed a label specialized for electric cable installed on a transit bridge, which could enable workers to locate, identify and service individual conduits.
Published: November 15, 2019

Facing a U.S. Department of Transportation (DOT) deadline to complete a bridge’s electrical installation within four weeks, RFID company Vizinex custom-designed and manufactured an RFID tag for 600 pieces of conduit. With the passive UHF RFID tag, the DOT could manage its maintenance schedule automatically for each piece of conduit based on RFID tag reads.

Vizinex provided the RFID tag to systems integrator Barcodes Inc. for its customer, an electrical contractor that has asked to remain unnamed. The contractor had already completed the electrical installation and simply needed to tag the conduit according to the DOT’s specifications. The project started just as the contractor’s electrical installation deadline approached.

The contractor had expected this final step of the project to be fairly straightforward: simply applying the tags dictated, according to very specific requirements from the DOT. However, what had seemed like a simple task—printing and encoding RFID tags to each piece of conduit installed on the bridge—became more challenging when the contractor and its label provider, Barcodes, found that the RFID tag the transportation agency was requesting didn’t yet exist.

Any delay in the labeling of conduit would result in a penalty for the contractor. Therefore, Barcodes took its challenge to Vizinex. The Pennsylvania-based RFID technology company considers itself adept at developing special products in short timeframes and with constrained budgets, says Ken Horton, Vizinex’s CEO. Barcodes has a long-standing relationship with Vizinex and took its challenge directly to the RFID company.

The DOT required a high-performing passive UHF RFID adhesive label that could be attached directly to the metal conduit. The RFID tag would need to be interrogated by a handheld reader from a distance of up to 30 feet. The agency also required human-readable printed information on the front of the label. The tag came with specific drawings and dimensions: about 12 inches by 2 inches.

In addition to performance, the specification targeted durability requirements to ensure that the RFD tag could be interrogated by a reader (and that the human-readable text remains legible) long after the bridge work was completed. “It was so specific, in fact, that when we saw the drawing, we expected that there was a product out there that met those requirements,” Horton recalls. Since that turned out not to be the case, the RFID technology company decided it had to develop and manufacture a new customized tag for this application.

Most Vizinex tags consist of printed circuit boards, with the RFID antenna applied on the top layer. In this case, the company had to employ quick-turnaround printed circuit boards from its manufacturer, and it custom-designed the antennas required. The engineer used standard circuit board design tools to create the antenna, as well as finite element analysis to simulate the antenna’s performance.

Vizinex took advantage of the large footprint of the DOT tag to create an antenna that would provide a long read range. Because handheld readers can vary in their effectiveness with RFID tag reading, the company designed the tag so that the smallest, lowest-range reader could still accomplish a 30-foot RFID tag read

The thickness of the printed circuit board serves as a spacer to prevent any interference from the metal to which the tag is attached, making it an effective on-metal tag. Within approximately three weeks, the engineers were able to design three versions of the tag, thereby enabling the manufacturer to create prototypes for each. Those prototypes were tested and the most effective version was selected for production. Vizinex also built a recess into the label, to which zip ties could be attached, in order to affix the label to the conduit.

In parallel, Horton says, Barcodes worked on the human-readable printed portion of the label, which required specialized color coding. “We were together able to provide the finished product to the contractor in time to avoid any penalties,” he states. “It was a win all around.”

Vizinex and Barcodes did not provide the software that the DOT would use to read the tags. With the RFID-enabled labels, depending on the software used, any servicing, inspections and life history of each conduit can be stored automatically, without the need for large amounts of paperwork in the field. The DOT is requiring RFID for some road and bridge work projects in certain states, Horton notes.