Sensor RFID Tags | Passive Temp & Humidity Logging Transponders

Sensor RFID tags: The Tag That Knows the Environment

A plain RFID tag answers "who am I?". A sensor RFID tag answers "who am I, and what temperature/humidity/shock have I seen since last read?". Passive sensor tags harvest energy from the reader field to power a micro-sensor and Store samples in on-chip memory (or mirror to reader). No battery, no wiring, 10-year life.

Variants

- Temp-only: HF or UHF, −40 to +85 °C, ±0.5 °C, 64–2048 sample buffer.

- Temp + humidity: capacitive RH sensor, 0–100% RH ±3%.

- Shock/vibration: MEMS accelerometer event latch.

- Tilt: mercury-free tilt flag.

Scenes

- Cold chain: vaccine box tag logs excursion, read at clinic, reject if >8 °C 30 min.

- Autoclave: HF sensor tag in tray logs 134 °C/3 bar dwell, proves sterilization.

- Concrete: embedded UHF temp tag logs curing gradient.

- pallet: humidity tag in tropical transit.

How Read Works

Reader sends special command, tag returns last N samples + current value. Some support threshold alarm bit set in user memory.

Limitation

Passive sensor tags sample only when energized unless they carry a tiny supercap (hybrid). For continuous logging in transit, semi-passive (battery-assisted) is used—but then it is no longer pure passive.

CTA: industrialrfid.com — temp UHF, RH HF, shock logger.