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Cold chain monitoring: how multi-sensor IoT devices protect high-value assets

#iot #coldchain #embedded #assettracking

Temperature alone isn’t enough. Your vaccine cargo could have stayed in range all the way to the destination, yet be compromised due to lack of monitoring of parameters such as humidity, shock or light. Here’s how IoT tracking devices help ensure end-to-end control by covering all bases.

Why single parameter monitoring is inadequate

Single parameter loggers typically monitor temperature only. This may be sufficient for simple food shipments. But in case of biologics, mRNA vaccines, blood products and precise pharmaceuticals, more than one condition affects integrity.

Even when your blood bag is kept at proper temperature levels, it can still be compromised due to shock from being constantly moved around. Even when you keep your insulin vial chilled but it is exposed to sunlight in a warehouse, it becomes ineffective.

The five sensors that matter

Temperature
Essential sensor for pharmaceuticals. Must record continuously at 30-60 second intervals for the entire trip.
Range: -80°C to +60°C

Humidity
Required for lyophilized products and packaging integrity.
Range: 0-100% Relative Humidity

Shock and vibration
Tracks accidental drops, bumps, and excessive vibration.
Threshold: adjustable G-forces

Light exposure
Triggers when a package is opened without authorization or exposed to UV radiation.
Measures lux and UV light range

GPS location
Links each sensor reading to an accurate GPS location — crucial for breach analysis.
Accuracy: 3-5 meters outdoors

Example of payload from multi-sensor cold chain tag

All data points collected from a well-designed cold chain tag should be part of the payload structure, including all sensor readings, location, and the breach flag:

{
  "assetId": "VIAL-7821-B",
  "ts": "2025-03-14T09:32:11Z",
  "sensors": {
    "tempC": 4.2,
    "humidityPct": 58.3,
    "shockG": 0.3,
    "lightLux": 0,
    "lat": 43.6532,
    "lng": -79.3832
  },
  "breach": false,
  "breachType": null
}
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How a breach flag is calculated on the edge device
The breach flag must be calculated on the device itself prior to sending. Below is a simplified example of Node.js code for how this can be done:

function evaluateBreach(reading, thresholds) {
  const breaches = []

  if (reading.tempC > thresholds.maxTemp ||
      reading.tempC < thresholds.minTemp) {
    breaches.push('TEMPERATURE')
  }
  if (reading.humidityPct > thresholds.maxHumidity) {
    breaches.push('HUMIDITY')
  }
  if (reading.shockG > thresholds.maxShock) {
    breaches.push('SHOCK')
  }
  if (reading.lightLux > thresholds.maxLight) {
    breaches.push('LIGHT_EXPOSURE')
  }

  return {
    breach: breaches.length > 0,
    breachType: breaches[0] ?? null,
    allBreaches: breaches
  }
}
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Warning Severity Matrix

Type of Breach Severity Action
Temperature excursion Critical Send immediate SMS + webhook + ship notification
Humidity breach Critical Send alert + hold shipment until investigation
Shock exceeded threshold Moderate Log event + contact receiving team
Light exposure detected Moderate Send alert to inspect on receipt
Route deviance from GPS path Monitor Log incident + contact logistics coordinator

Compliance tip:

To meet FDA 21 CFR Part 11 and EU GDP requirements, all readings must be timestamped with tamper-proof timestamps, and an unbroken chain of custody must be maintained in the logs. Design your data architecture such that records cannot be altered after being written; append-only database or blockchain anchoring can work here.
Connectivity options for cold chain tags
All cold chain environments aren’t always covered by reliable cellular networks. Select your connectivity based on the deployment:

Cellular (LTE-M / NB-IoT) - optimal when used for cold chain transportation over long distances and large geographies. Global coverage, near-real-time monitoring, moderate power consumption. BLE + Gateway - best option when you have fixed gateways in your warehouse/facilities. Lowest power consumption. LoRaWAN - best suited for remote cold storage and rural/distance-based distribution centers. Satellite (Iridium/Starlink) - backup connectivity for locations beyond the reach of terrestrial networks.

AssetTrackPro’s cold chain tags are equipped with multiple sensors to monitor temperature, humidity, shock, lighting, and location (GPS). Threshold configuration, breach alerts, and automatic compliance report generation are included. Cold chain deployments at various companies, including pharmaceuticals, hospitals, and blood banks. Learn more →

Building a cold chain monitoring system? AssetTrackPro's IoT devices cover every sensor that matters — with compliance reporting ready out of the box.
Explore AssetTrackPro ↗

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