Label, not a device
CoolTag is built around the Axzon AZN5201-AFR — a flexible peel-and-stick label with a thin printed battery. There is no separate enclosure to manage and no return logistics: the label travels with the product.
COOLTAG
The autonomous peel-and-stick RFID temperature logger inside Cooldat®.
CoolTag is a low-cost, label-style temperature logger and UHF RFID transceiver powered by the Axzon Opus IC. A single 33 × 100 mm flexible label records an end-to-end, encrypted temperature history for any cold-chain item, then surrenders that history wirelessly to any UHF RFID portal, handheld, or mobile reader running QDatFX or QDatDroid.
- •4096-sample encrypted flash log
- •RAIN UHF 860–960 MHz, ISO 18000-63 / EPC Gen2 v2.0.1
- •-30 °C to +60 °C with 0.125 °C resolution
WHAT IT IS
A printed-battery RFID label that logs temperature on its own
Autonomous logging
Once armed by a QDatFX or QDatDroid reader session, the tag autonomously measures and records temperature at user-defined intervals (30 s to 8 h). No reader contact is required during the journey.
End-to-end chain of custody
Samples are encrypted at the moment of measurement and written to on-chip flash. Each reading can carry an AES-128 authentication code so the recipient can prove the log was not altered after the fact.
Visible alarm without a reader
An on-board LED blinks one pattern for "armed and active logging" and another for "temperature set-point alarm" — so warehouse staff can triage exceptions without scanning the tag.
Read in passing
Logs are surfaced wirelessly when the item crosses any UHF RFID portal, a handheld trigger, or a mobile reader phone. Alarm state can be detected without downloading the full log.
Identity image
THE COOLDAT SOLUTION
CoolTag + QDatDroid + QDatFX + QDat.io = Cooldat®
Cooldat® is the name of the complete solution. It is not a single product — it is the combination of the CoolTag sensor, two reader clients (one handheld, one fixed), and the QDat.io spatiotemporal intelligence platform that ties them together over a secure transport.
CoolTag
The autonomous peel-and-stick UHF RFID temperature logger label — the sensor at the edge. Records 4096 encrypted samples on its own and carries them with the item.
QDatDroid
The handheld RFID reader client — Android app paired with RE40-based handhelds (Zebra RFD40, TC22R) and the EM45 mobile RFID phone. Arms CoolTags and reads them in the aisle, at the dock, or on the floor.
QDatFX
The fixed RFID reader client — runs against Zebra FX7500 and FX9600 portal readers at chokepoints, dock doors, and packing lines. Same arming and reading workflows as QDatDroid, in a fixed footprint.
QDat.io
The spatiotemporal intelligence platform — the cloud backend that ingests the streams, stores the time-series, exposes REST and MCP APIs, and powers alarms, dashboards, and the AI roadmap (QCoolDat predictive shelf-life, QRecover predictive margin recovery).
WSS MQTT transport
Reader clients talk to QDat.io over MQTT carried on secure WebSockets (WSS) — one always-open, TLS-protected pipe per client. Works through corporate proxies, survives roaming, and streams CoolTag samples, alarms, and reader telemetry in real time.
Why call it Cooldat®
Each part of the stack is a discrete product, but a cold-chain deployment only works when all four are in place. Cooldat® is the shorthand for the assembled solution: CoolTag in the field, QDatDroid and QDatFX at the reader edge, QDat.io in the cloud, WSS MQTT in between.
DATA FLOW
How a CoolTag sample reaches QDat.io
1 — CoolTag records
The tag autonomously samples temperature at its configured interval and writes each sample to on-chip encrypted flash. No connectivity required during transit.
2 — Reader meets tag
When the item passes a fixed portal or is scanned by a handheld, the reader interrogates the tag over RAIN UHF (860–960 MHz) and pulls the log — or just the alarm flag — wirelessly.
3 — Reader client publishes
QDatFX (on the fixed reader) or QDatDroid (on the handheld) is the client that wraps the raw RFID exchange into structured CoolTag stream messages.
4 — WSS MQTT to QDat.io
The reader client publishes those messages to QDat.io over an MQTT connection carried on secure WebSockets. TLS-encrypted, NAT-friendly, low-latency, and resilient to intermittent links.
5 — QDat.io ingests
The broker writes into time-series storage, fires alarm and exception workflows, and exposes the history through REST and MCP APIs for dashboards, integrations, and AI agents.
CoolTag stays the source of truth
The 4096-sample encrypted log on the tag is the canonical record. QDat.io ingests, replicates, and reasons over those logs — but the cryptographic proof of each sample lives on the CoolTag itself.
RFID PERFORMANCE
Specifications
Worldwide RAIN UHF
860–960 MHz operation, ISO/IEC 18000-63 and EPCglobal Gen2 v2.0.1 compliant.
Chameleon self-tuning RF
Autonomous impedance matching that keeps the tag tuned across frequencies, humidity, and packaging variation.
On-chip RSSI (OCRSSI)
Received power sensor reported back to the reader for diagnostics and zone detection.
Passive sensitivity
-9 dBm read, -6 dBm write — about 4 m read range in air without a battery.
Battery-assisted sensitivity (BAP)
-17 dBm read and write — extends read range past 8 m in air when the printed battery is active.
Compliance
EPC Class 1 Gen 2 v2.0.1 and ISO 18000-63, with Gen2v2 data-read protection and AES128 data integrity/secrecy.
DATA LOGGING
How the tag records
Flash memory capacity
4096 temperature samples held in non-volatile flash that the reader can only read, never write.
Real-time clock
Continuous RTC with 0.2% accuracy once the battery is activated.
Programmable intervals
User-selectable logging intervals from 30 seconds to 8 hours.
Delayed start
Logging can begin immediately or after an integer number of intervals.
Uninterruptible logging
Once armed, logging cannot be altered, paused, or cleared over the air.
Tamper flag
Each sample carries a tamper flag so out-of-band events are surfaced in the log.
DURATION VS. INTERVAL
How long a CoolTag actually logs
Two ceilings cap a logging session. The battery supports up to ~3 months of active logging. The flash memory holds exactly 4096 samples. Whichever runs out first ends the session. Below ~32-minute intervals the memory is the bottleneck; above it the battery is. Note that the manufacturer-supported minimum interval is 30 seconds — entries below that line are extrapolated.
| Interval | Time to fill 4096 samples | Effective duration (with 3-month battery cap) | Bottleneck |
|---|---|---|---|
| 10 s(below spec) | ~11 h 22 min (0.47 days) | ~11 h 22 min | Memory |
| 30 s | ~34 h 8 min (1.4 days) | ~34 h 8 min | Memory |
| 1 min | ~68 h 16 min (2.8 days) | ~68 h 16 min | Memory |
| 10 min | ~28.4 days (4 weeks) | ~28.4 days | Memory |
| 30 min | ~85.3 days (≈2.8 months) | ~85.3 days | Memory (just barely) |
| 1 h | ~170.7 days (≈5.6 months) | ~3 months | Battery |
| 2 h | ~341.3 days (≈11.2 months) | ~3 months | Battery |
| 3 h | ~512 days (≈16.8 months) | ~3 months | Battery |
| 4 h | ~682.7 days (≈22.4 months) | ~3 months | Battery |
| 5 h | ~853.3 days (≈28.0 months) | ~3 months | Battery |
| 6 h | ~1024 days (≈33.7 months) | ~3 months | Battery |
| 7 h | ~1194.7 days (≈39.3 months) | ~3 months | Battery |
| 8 h | ~1365.3 days (≈44.9 months) | ~3 months | Battery |
Rule of thumb: flash time = 4096 × interval. Pick the longest interval your application can tolerate so the battery, not the memory, is what ends the session.
TEMPERATURE SENSOR
How the tag measures
Operating range
-30 °C to +60 °C.
Resolution
0.125 °C.
Typical accuracy
±0.5 °C between 30 °C and 60 °C; ±1.0 °C between -25 °C and 60 °C.
Calibration
2-point factory calibration at 30 °C and 60 °C, with optional user re-calibration.
Sensor topology
PTAT solid-state sensor digitized by an on-chip ADC, then encrypted before being written to flash.
Battery monitor
Dedicated ADC verifies battery voltage at every logging event so out-of-range samples are flagged.
SECURITY
Tamper-evident by design
Identity
128-bit Unique Identifier (TID) and 128-bit EPC.
Memory passwords
Password control of TID, EPC, and User memory banks per EPC Gen2.
AES-128 keys
128-bit AES Encryption Keys, ISO/IEC 29167-10.
Sample date authentication
Each sample can be cryptographically authenticated, even after export to a downstream archive.
Air-gap protection
Flash memory cannot be written over the air — only the logger itself writes to flash.
Read modes
Clear or encrypted data, with or without an appended authentication code (4 combinations).
ENERGY MANAGEMENT
Printed battery, multi-week life
Sleep current
≤1 nA at room temperature — defines the >1 year shelf life.
Standby current
140 nA typical (RTC running, ready to log).
Operating life
Up to 21 days (3 weeks) of logging from a 100 µAh printed battery.
Battery range
1.8 V minimum to 3.0 V input range.
Printed power source
Thin, flexible, printed battery — REACH/SVHC, RoHS, and EU battery-directive compliant.
Maximum RF input
+3 dBm at the IC RF receiver ports.
MEMORY
On-chip storage map
TID memory
1024 bits (64 words).
EPC memory
Formats up to 256 bits (16 words).
User memory (Flash)
4240 words total, including 4096 words of log data.
User memory (MTP)
2304 bits (144 words) of multi-time programmable configuration.
Reserved memory
320 bits (20 words).
MTP endurance / retention
100k cycles; 20+ years retention after 10k cycles at 85 °C.
Flash endurance / retention
20k+ cycles; 100 years at 25 °C, 25 years at 85 °C, 10 years at 125 °C.
PHYSICAL & STORAGE
Label, shelf life, and packaging
Label format
33 × 100 mm flexible peel-and-stick label (AZN5201-AFR).
LED indicator
Two-state blink pattern signals "armed and active logging" or "temperature set-point alarm."
Programmer
Arming with FX7500/9600 with QDatFX or RE40-based handheld such as RFD40, TC22R via QDatDroid and EPC programming via Zebra ZT411 RFID printer.
Storage temperature
+15 °C to +35 °C.
Storage humidity
40% to 60% RH.
Storage material
Sealed MPET bags, no desiccant.
Shelf life
>1 year with more than 80% of original capacity.
LOGGER LIFECYCLE
The five states a CoolTag passes through
No-Battery State
Reader has passive RF access to MTP memory — EPC, user, and configuration can be staged before battery insertion.
Sleep State
Battery installed but isolated. ≤1 nA drain. This is the shelf-life state.
Standby State
Reader command wakes the RTC; battery drain rises to ~100 nA. Defines operating life.
Ready State
Once the RTC is set, configuration is locked from MTP into the real-time controller. Cannot be altered without removing the battery.
Logging State
Periodic logging events (≈80 ms each) write encrypted samples to flash. Stops when full, when battery falls below threshold, or at the programmed count.
ARCHITECTURE
Inside the Opus IC
Battery power domain
Real-time clock, battery power management, and real-time controller — held at 1.5 V from battery activation until end of session.
Main power domain
Charge pump, modulator/demodulator, main processor, temperature sensor, 4k-word flash, 4 kb MTP, and crypto engine.
Powering modes
Passive (RF energy harvesting) for reader I/O; battery-driven for the logging events themselves; BAP mode for extended read range.
Chameleon self-tuning
Autonomous impedance matching adapts to frequency, antenna detuning, and moisture — sensitivity stays consistent across the 860–960 MHz band.
Read range curve
Passive: ~4 m peak around 900 MHz. Battery-assisted: >8 m in air.
Logging event timing
≈80 ms per logging event, during which passive RF communication is briefly blocked while the encrypted sample is committed to flash.
COMPLIANCE AND STANDARDS
RFID
EPC Class 1 Gen 2 v2.0.1; ISO/IEC 18000-63; Gen2v2 data-read protection with 32-bit Access Password.
Cryptography
AES-128 data integrity and data secrecy; AES key handling per ISO/IEC 29167-10.
Battery directives
EU Battery Directive 2006/66/EC, REACH/SVHC, EU Packaging Directive 94/62/EC, US CONEG.
Hazardous substances
Printed battery complies with the substance restrictions of the EU RoHS Directive 2002/95/EC (lead, cadmium, mercury, hexavalent chromium, PBB, PBDE).
Standard pack
50 CoolTags per standard CoolKit; stored in sealed MPET bags at 15–35 °C and 40–60% RH, without desiccant.
IP ownership
Underlying Opus IC is covered by the Axzon U.S. patent portfolio (see axzon.com/patents).
DEPLOY COOLTAG
Item-level cold-chain data, from label to AI
Talk to us about a CoolKit deployment — the 50-CoolTag starter pack, paired EcoTags, Zebra readers, and the Cooldat® cloud — sized for your producer or retailer operation.
CoolTag is built on the Axzon AZN5201-AFR Peel & Stick Logger. Manufacturer references: Axzon flexible peel-and-stick logger · AZN5201 data brief (PDF).