Lock Box Hail Message Transponder Battery Life

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Solution Overview

Problem

Previous electronic lockbox systems face battery drain issues due to constant listening for radio or light beam messages, leading to limited battery lifetime and inconvenience for users, especially when accessing properties.

Innovation Solution

An electronic lock box system that uses a wireless portable transponder to respond to hail messages from the lock box with encrypted data, authenticates using a time-sensitive encryption key, and sends access event records to a central clearinghouse computer via a wide area network, while maintaining low power consumption by activating radios only when necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the lock box continuously listens for radio messages to enable immediate access, then access responsiveness is improved, but battery lifetime deteriorates

Engineering Contradiction:

Improveaccess responsivenessVSAvoidbattery lifetime

Core Design Contradiction:

SpeedVSDuration of action of stationary object

Solution Approach 1:

Instead of the lock box continuously listening for messages (traditional approach), the system inverts the communication initiative to the transponder. The lock box periodically transmits hail messages and waits for responses, eliminating the need for continuous reception monitoring while maintaining immediate access capability when a transponder is present.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The lock box employs periodic hail message transmission instead of continuous listening. This periodic action allows the system to maintain access responsiveness during active periods while conserving battery power during idle periods, directly resolving the contradiction between speed and battery lifetime.

Inventive Principle:

Principle #19Periodic action

2Loss of information

If the electronic key uses cellular telephone systems for wide area communication, then real-time data transmission is improved, but battery drain deteriorates

Engineering Contradiction:

Improvedata transmission capabilityVSAvoidbattery drain

Core Design Contradiction:

Loss of informationVSUse of energy by moving object

Solution Approach 1:

The transponder's wide area network radio operates dynamically - activated only when needed for clearinghouse communication and deactivated otherwise. This dynamic operation allows real-time data transmission capability when required while minimizing battery drain during normal lock box access operations.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent extracts the wide area network communication function from the continuous operation mode and separates it from the low power radio access protocol. This allows WAN communication to occur only when necessary for data synchronization with the clearinghouse, reducing overall battery consumption while maintaining data transmission capability.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If the lock box always maintains radio listening capability, then access reliability is improved, but energy consumption deteriorates

Engineering Contradiction:

Improveaccess reliabilityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The system inverts the traditional master-slave communication model where the lock box continuously monitors for access requests. Instead, the lock box becomes the active transmitter of hail messages and the transponder becomes the responsive element, maintaining access reliability while eliminating continuous reception power consumption.

Inventive Principle:

Principle #13The other way round (Inversion)

4Speed

If the transponder continuously monitors for lock box messages, then access responsiveness is improved, but battery lifetime deteriorates

Engineering Contradiction:

Improveaccess responsivenessVSAvoidtransponder battery lifetime

Core Design Contradiction:

SpeedVSDuration of action of moving object

Solution Approach 1:

Both the lock box and transponder employ periodic communication patterns rather than continuous monitoring. The lock box transmits hail messages periodically, and the transponder responds periodically when in range, enabling fast access when needed while extending battery life through reduced active communication time.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUSRE46539E1Electronic lock box proximity access control

Publication Date: 2017.09.05 SENTRILOCK LLC

AI summary

An electronic lock box system includes a wireless portable transponder that communicates with an electronic lock box using a low power radio link. The portable transponder includes: a wide area network radio to communicate to a central clearinghouse computer, a motion sensor to activate its wide area network radio, and a connector to communicate with a secure memory device. The electronic lock box sends a hail message that is intercepted by the portable transponder; the hail message includes identification information. The portable transponder responds with a message that includes a time sensitive encryption key; the lock box authenticates this response message using its own time sensitive encryption key. If the messages are authenticated, the lock box sends an access event record to the portable transponder, and this access event record is stored in the secure memory device. If a wide area network is available, the portable transponder sends the access event record to the central clearinghouse computer.