At Manor, RFID Keeps Food From Spoiling

In addition, the company determined the processes it would go through when using the temperature-monitoring application. For example, Manor decided it would notify store managers rather than department managers, such as the head of the beef department, if the system detected that a refrigerator had stopped working.

At the end of 2004, Manor opted to deploy the technology at 30 supermarkets. IP01 manufactured the hardware and began implementing Place and Track in 2005. The tags consume a maximum of 15 milliwatts to send out their long-range 868 MHz signals, using a custom air-interface protocol designed to minimize battery use. The tags' lithium-ion batteries, provided by Saft, are guaranteed to last three years. Tags can function at temperatures as low as -35 Celsius (-31 degrees Fahrenheit).

RFID tag with built-in temperature sensor

Each tag contains a temperature sensor and a 16-kilobyte memory module able to hold 8,000 temperature readings. The tag is encased inside a triangular plastic housing about 14 centimeters long by 4 centimeters high. The housing comes with a mounting clip that can be slipped into bases installed in refrigerators and freezers. The application requires only a few interrogators since a tag's signals (consisting of a unique ID number and a temperature reading) can travel a distance of 50 and 200 meters, respectively, inside a store. If the tag were deployed outdoors, its signals could be read at even further distances.

Specially designed RFID readers, which IP01 calls gateways, have been mounted in a store's ceiling. Every 15 minutes, the gateways forward the tag data they have collected to a server hosted by IP01, which not only designed and implemented the system, but also performs the monitoring services for Manor.

If an alert is serious, IP01 calls stores directly, then enters the actions it has already taken onto a password-controlled Web site that store managers can view. The Web site includes maps of stores indicating the tags' locations, making it easy for a manager to find the freezer or refrigerator in question. On this same Web site, managers can inform system monitors about their cleaning plans for freezers and refrigerators, to ensure that unnecessary alarms are not generated.

Approximately 1,800 tags are presently in use. On average, Manor receives a total of about 10 alerts per day from the 30 stores using the system, with far fewer alerts received in winter than in summer. Each month, the system generates a report that tallies up alerts generated during that period. These reports have turned out to be an unanticipated benefit for Manor, by providing the retailer with valuable information for making business and operational decisions.

For instance, a store with frequent alerts might be renovated before one with fewer alerts. Another example: Manor discovered that some freezers and refrigerators had mechanical problems, and was able to provide temperature histories to repair technicians to help them troubleshoot those problems.