NFC Belt Sensor

Battery-free flex polyimide sensor embedded in conveyor belt rubber

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NFC powered conveyor belt damage sensor PCB

The Challenge

Detect conveyor belt damage before catastrophic failure. Sensors are embedded in the belt itself with no batteries (impossible to maintain), must survive continuous flexing and impact from ore loading.

The Solution

Flexible polyimide PCB with an NFC antenna coil that harvests power from reader stations along the conveyor frame. When the sensor passes a reader, it powers up, takes a strain measurement, and transmits back over the same NFC link, all in the fraction of a second it takes to pass by. The flex PCB is thin and compliant enough to bond into the belt rubber without creating a stress concentration.

Results

Early detection lets the mine schedule repairs during planned downtime. The battery-free design is install-and-forget. Some sensors have been through millions of flex cycles without failure.

How it works without a battery

Reader stationon the conveyor frameNFC antenna coilharvests powerStrain measurementbattery-freefield + data
The reader powers the sensor as it passes. The coil harvests energy from each reader station, the sensor takes its strain reading and answers over the same NFC link in the fraction of a second it is in range, and the thin polyimide flex bonds into the belt rubber.
sensor runs above 1.8 V011.83 V-60-3003060 msTime from the reader centreStorage capacitordots mark where the 12 ms measure and reply finishes2 m/s, 58 ms above 1.8 V4 m/s, 35 ms above 1.8 V6 m/s, 28 ms above 1.8 V
A fraction of a second to do everything. The sensor only has power while it is close enough to a reader, and the faster the belt runs the shorter that window gets. At 6 m/s the supply stays up for about 28 ms, so the strain measurement and the reply over the same NFC link are written to finish in 12 ms, with margin left at the fastest belt speed.

Have a Similar Challenge?

Embedded wireless sensors for harsh environments are part of the practice.

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