Smartphone Multi-Transponder Key Emulation
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Solution Overview
Problem
Conventional vehicle keys are model-specific and require dealer involvement for programming, limiting their versatility and convenience, especially for newer vehicle models with complex RF and LF protocols.
Innovation Solution
A smartphone with integrated multi-transponder mode key functionality, including a highly configurable RF transmitter and LF transponder, capable of emulating various key fob systems by switching between carrier frequencies and configuring protocol parameters to work with different vehicle models, using a single chip package and existing antenna structures for communication and energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional vehicle keys are used, then each key is specific to one vehicle model, but this limits versatility and requires multiple keys for different vehicles
Solution Approach 1:
The smartphone is configured to emulate multiple different key types (transponder, remote keyless entry, passive entry) within a single device. The system can switch between different communication protocols and frequencies to work with various vehicle models, eliminating the need for multiple physical keys.
Solution Approach 2:
The key emulation system changes operational parameters such as carrier frequency, modulation type, and communication protocol to match different vehicle key types. This allows a single smartphone to adapt its behavior to communicate with various vehicle access systems.
2Ease of operation
If dealer involvement is required for key programming, then key security is maintained, but this reduces convenience and increases time cost
Solution Approach 1:
The system enables users to program additional keys themselves without dealer involvement. The vehicle's existing key learning capability is leveraged to allow owners to program new keys (including smartphone emulations) by following simple procedures like turning the ignition on and off multiple times or using the existing key to trigger learning mode.
3Adaptability or versatility
If multiple transponder modes are integrated into a single device, then versatility is improved, but device complexity increases
Solution Approach 1:
Multiple transponder emulation modes (different key types and protocols) are merged into a single smartphone application. The system combines RF transmitter, LF transponder, and passive entry capabilities in one integrated solution, managing complexity through software configuration rather than separate hardware devices.
4Volume of moving object
If existing antenna structures are used for RF and LF communication, then device size is minimized, but communication reliability may be compromised
Solution Approach 1:
Existing smartphone antennas designed for cellular and wireless communications are made multi-functional by configuring them to operate at different frequencies and protocols. The same physical antenna structure serves both original communication purposes and new key emulation functions, eliminating the need for additional dedicated antennas.
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
Enables a single device to act as a legitimate access and start authorization for multiple vehicle models, reducing the need for multiple keys and dealer involvement, while minimizing memory and processing power, and accommodating various communication modes including passive start and entry.
Implementation Method 1
The vehicle and the key share a common secret. The algorithm that generates an appropriate code is called a rolling code. A command, such as lock or unlock, is transmitted along with the next valid rolling code.
Implementation Method 2
The coil communicates an LF signal to a transponder in the head of the key, which changes or validates a secret code, which allows the engine to start.
Implementation Method 3
Limp-home mode for starting the engine for a car with passive start is the same as the RKE system with anti-theft, which means that the fob will be placed near the immobilizer coil, which will provide energy to the microcontroller in the fob to respond with a secret code
Data Source
AI summary
A smartphone having: a configurable radio frequency transmitter; a configurable low frequency transponder with at least one low frequency coil; and a smartphone application program that is controlled by a cloud service and that is configured to configure the radio frequency transmitter and the low frequency transponder with protocol parameters and initial data values such that the low frequency transponder mimics a virgin key device that can be programmed to a particular vehicle model.