The KelvinTrack Android app
Far more than a thermometer. The app reads your KelvinTag sensors over Bluetooth, turns a simple phone into a gateway, and its AI engine analyses the thermal signature of your equipment to warn you when a component starts to weaken - before it fails.
- 3 years of readings in the sensor
- No missing points
- Bluetooth up to 50 m
- No location permission
The essentials
A classic thermometer answers "is it cold enough right now?". The KelvinTrack app answers a far more useful question: "is my equipment degrading?". Free on Google Play (Android 12+), it reads your KelvinTag sensors over Bluetooth up to 50 m, turns a phone into a gateway with no subscription, and its AI watches the health of every refrigeration part. Each sensor holds 3 years of readings in memory: even away from the phone, no point is ever lost.
Updated July 2026.
Predictive diagnostics of cold-chain components
Every part of a refrigeration system - compressor, refrigerant, condenser, defrost, fan - leaves a signature in the temperature curve. An outright failure is almost always preceded by weeks of small signals. The human eye misses them; KelvinTrack's AI, trained to recognise these signatures in the continuous readings, does not. It turns those signals into a clear, component-by-component status.
Here, five parts are healthy, the thermostat has been flagged "to check" for three days, and the fan is not measurable in this setup. The message is concrete: a technical intervention is recommended in the coming weeks - not an emergency on a Sunday night.
In all honesty: temperature monitoring reveals symptoms, it does not replace a technician diagnosis - it orients it and triggers it at the right time. Some signatures confirm over time and sharpen with several sensors. Not every failure is announced: a sudden mechanical break can still happen.
Four early signals, readable in the curve
Most failures begin with a slow drift, not a sudden stop. The value shift is going from reactive to preventive: acting during the alert window, while a maintenance visit is still enough.
| Early signal | What it often reveals |
|---|---|
| The baseline rises by a few tenths over several days | Refrigerant leak, fouling, tired compressor |
| Recovery time lengthens after each opening or defrost | Loss of capacity (refrigerant, condenser, fan) |
| Cycles get closer together or become erratic | Door seal, controller, compressor short-cycling |
| The defrost pattern changes | Failing defrost heater or timer |
The full reasoning, part by part, is detailed in our approach to compliance and prevention.
No measurement point ever lost
The KelvinTag sensor is not a mere transmitter: it is a standalone logger holding 3 years of readings in its own memory. Gateway off, phone away, internet down: it keeps recording, point by point.
When you come back in range, the app detects the gap in the history and quickly pulls the missing points over Bluetooth. Your curve is complete, with no manual step - and that curve is what stands as proof during an inspection.
Bluetooth range reaches up to 50 m depending on the environment: in most kitchens, storerooms and labs, a single phone covers the whole installation.
Spec sheet
- Sensor memory
- 3 years of readings, no missing points
- Catch-up
- Fast retrieval of missing points when back in range
- Bluetooth range
- Up to 50 m depending on the environment
- Minimum Android
- Android 12
- Location
- No location permission requested
- Price
- Free on Google Play, no subscription
Privacy included: the app scans Bluetooth without ever asking for your location.
What the app does
50 m Bluetooth gateway
Reads your KelvinTag sensors over Bluetooth up to 50 m depending on the environment. An Android phone, even an old one, becomes the WiFi gateway - with no recurring cost.
AI predictive diagnostics
The AI analyses each unit's thermal signature and flags the component that is weakening before an outright failure.
3-year memory, zero gaps
Each KelvinTag holds 3 years of readings in its memory. Back in range, the app quickly pulls the missing points: the curve stays complete.
Real-time alerts
Threshold breaches trigger an immediate alert, relayed to your dashboard and your notifications.
HACCP history
The full history is kept and stands as proof during an inspection - continuous traceability, at night, on weekends and holidays.
Free, no subscription
Free on Google Play, no per-sensor subscription. Install it on as many phones as you need; each device in range strengthens coverage.
Your phone becomes the gateway
No dedicated hardware needed to start: an Android phone, even an old one, left on your WiFi, sends your sensor readings to your dashboard.
- 1
Install the free KelvinTrack app on an Android phone.
- 2
Keep it on your WiFi, within range of your KelvinTag sensors.
- 3
Readings flow automatically to your dashboard. No subscription.
Torn between a phone gateway and a dedicated 5G gateway? The app guide (iPhone and Android) compares the two options in detail.
Frequently asked questions about the Android app
How does the app detect a weakening component?
- Every part of a refrigeration system leaves a signature in the temperature curve. By tracking that curve continuously, the app spots the slow drifts that precede a failure - a rising baseline, a lengthening recovery time, a changing defrost pattern - and flags the component to check.
Does the diagnosis replace a refrigeration technician?
- No. Temperature monitoring reveals symptoms; it does not replace a technician diagnosis, it orients it and triggers it at the right time. Some signatures confirm over time and sharpen with several sensors. Not every failure is announced: a sudden mechanical break can still happen.
Do I need a dedicated gateway to use this app?
- No. The free Android app reads your KelvinTag sensors over Bluetooth and turns a simple phone, even an old one, into a WiFi gateway. No dedicated gateway to buy, no subscription for this setup. The Poliponet 5G gateway remains available as an option for larger sites.
What happens if I move away from the sensors? Are readings lost?
- None. Each KelvinTag sensor is a standalone logger holding 3 years of readings in its own memory, gateway present or not. As soon as the phone comes back into Bluetooth range (up to 50 m depending on the environment), the app detects the missing points and quickly pulls them in: the curve stays complete, with no manual step.
Which Android version is required?
- Android 12 or newer. This choice also lets the app scan Bluetooth without requesting the location permission: it never knows your position.
Where can I download the Android app?
- The app is available for free on Google Play. Install it on an Android phone, keep it on your WiFi within range of the sensors, and readings flow automatically to your dashboard.
Listen to what your cold chain is telling you
Download the free Android app: it turns a phone, even an old one, into a gateway with no subscription.