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RFID Brings Precision to Dice Rolls

EPC Solutions Taiwan has built a solution enabling 99.7 percent accuracy of automated dice-throw reads, with an RFID reader built into a throwing machine, six UHF RFID tags in each die and custom near-field antennas that can read tags with 1-centimeter precision.
By Claire Swedberg

The resulting system consists of a UHF RFID reader built into the floor of the machine, along with six tags in each die. The reader only reads the tag on the side of the dice facing down, and the software can thus calculate the throw results. For instance, if a die lands with one dot facing the machine floor, the software will recognize that a six has been rolled. EPC Solutions Taiwan's engineers selected UHF RFID using an Alien Technology Higgs 3 RFID tag chip, as well as an Alien ALR-F800 reader, built underneath the machine's rolling surface. The company custom-designed the antennas for both the tag and the reader.

When it came to creating RFID-enabled dice, the challenge was in the size. The company had to accommodate six tags, one on each side, and the tags needed to be uniquely identified within very close proximity. "We worked with the dice manufacturer to embed RFID chips into the dice during manufacturing process," Liu explains. However, he notes, the system would also require the reader to read only one side of each die—the one facing down on the surface—and not the other RFID chips.

EPC Solutions Taiwan had tested HF 13.56 MHz technology, but it found that there were inaccuracies in the dice reads. "We found there were many null points—blind areas," Liu says. "So we redesigned using UHF." Together with the dice manufacturer, the engineers were able to position the UHF tags in the dice properly so that the nearest tag would always be read, without any stray reads from those on the other sides of the dice. The tags come with a custom-designed loop antenna sized at 0.5 millimeter (0.02 inch) square.

In the dice machine, the reader antenna, designed by EPC Solutions Taiwan, measures approximately 16 centimeters (0.6 inch) in diameter. The near-field antenna accomplishes a read distance of about 1 centimeter (0.04 inch). "It took us half a year to develop the antenna, and another half a year to develop the dice," Liu states. A further challenge was ensuring that the tags could withstand the hard knocks of dice being thrown many times. In fact, he reports, it was designed to endure one million rolls.

Since the system was released, EPC Solutions Taiwan has found that gaming machines are achieving 99.7 percent reading accuracy. The firm has provided gaming solutions for casinos, Liu says, but this is the first RFID system it has offered that reads dice to identify a throw. According to Liu, his company specializes in challenging use cases for RFID that require custom designs for tag and reader antennas.

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