Dual-Sensor Shipment Data Logger for Temperature Drift Detection
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Solution Overview
Problem
Existing data loggers used for monitoring environmental parameters, such as temperature, suffer from inaccuracies due to sensor drift or shift, which are difficult to detect until recalibration, leading to costly and time-consuming recalibration processes.
Innovation Solution
A wireless data logger with two temperature sensors, one inside and one outside the housing, compares measurements to detect deviations exceeding a predefined limit, triggering a recalibration request, ensuring accurate temperature monitoring by isolating the secondary sensor from heat sources within the housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single temperature sensor is used in the data logger, then the device complexity is reduced, but the measurement precision deteriorates due to undetectable sensor drift
Solution Approach 1:
The patent implements a second temperature sensor that serves as a reference copy to detect drift in the first temperature sensor. By comparing measurements from both sensors, the system can identify when the first sensor drifts from accurate readings, thereby maintaining measurement precision without significantly increasing device complexity.
2Device complexity
If the temperature sensor is placed inside the housing, then the device integration is improved, but the measurement precision deteriorates due to heat interference from internal components
Solution Approach 1:
The second temperature sensor acts as an intermediary reference that is positioned outside the housing where it is not subjected to heat interference from internal components. This external reference sensor allows the system to distinguish between actual temperature changes and heat-induced measurement errors from the first sensor inside the housing.
3Reliability
If the communication module is kept on continuously, then the data transmission reliability is improved, but the energy consumption increases
Solution Approach 1:
The communication module operates periodically rather than continuously, transmitting data at scheduled intervals. This periodic operation significantly reduces energy consumption while maintaining adequate data transmission reliability for monitoring purposes, as the system only needs to communicate at specific intervals rather than maintaining a constant connection.
4Speed
If the first temperature sensor measures temperature while the communication module is on, then the real-time monitoring is improved, but the measurement precision deteriorates due to heat from the communication module
Solution Approach 1:
The system performs temperature measurements during periods when the communication module is not actively transmitting, such as during idle intervals between transmissions or when the module is in sleep mode. This preliminary timing of measurements avoids the heat interference period while still providing timely temperature data for monitoring purposes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for automatic identification of sensor failures, preventing the transmission of inaccurate data and ensuring reliable temperature monitoring by reducing heat interference, thus maintaining data accuracy and reducing the need for frequent recalibrations.
Implementation Method 1
a first temperature sensor configured for regularly measuring a first temperature of the shipment
Implementation Method 2
a second temperature sensor configured for regularly measuring a second temperature of the shipment, wherein the second temperature sensor is arranged in the vicinity and adjacent to an outer side of the housing
Implementation Method 3
a communication module configured to transmit the at least one environmental parameter including the stored measured temperature data of the shipment to an external data processing device
Data Source
Figure 1
Figure 2a~2b
Figure 3~4
AI summary
This invention relates to a wireless data logger, a method and a system for operating such a data logger, where the data logger is configured to monitor at least one environmental parameter of a shipment at least during transport of the shipment from an origin location to destination location, comprising: • a power source for powering the wireless data logger, • a first sensing device configured for regularly measuring an environmental related parameter, • a second sensing device configured for regularly measuring said environmental related parameter, • a processor, • a communication module operated by the processor configured to transmit the at least one environmental parameter to an external data processing device, wherein the measurement data from the first and the second sensing devices are processed by a processing device where the processing includes: • comparing the measurement data from the first sensing device with the measurement data from the second sensing device, where in case the comparison results in a deviation exceeding a pre-defined limit, • issuing a re-calibration request command for the wireless data logger.