SPI Keyboard Module for Compact Parking Meters
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Solution Overview
Problem
Single space parking meters lack the space for alphanumeric keypads due to their smaller size, limiting their ability to provide user input for functionalities like pay-by-space or pay-by-plate, which are common in multi-space meters.
Innovation Solution
The integration of a Serial Peripheral Interface (SPI) keyboard module with a parking meter controller, allowing for various keyboard layouts and low power consumption, enabling user input through a compact design that can support different functionalities without significant changes to the underlying meter components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If alphanumeric keypads are used in multi-space parking meters, then user input functionality is improved, but device size increases making them unsuitable for single-space meters
Solution Approach 1:
The keyboard is segmented into a compact matrix arrangement with row and column electrodes, allowing the input functionality to be divided into smaller detectable units that fit within limited space while maintaining full alphanumeric capability
Solution Approach 2:
The keyboard uses a two-dimensional matrix layout of electrodes instead of linear arrangement, enabling more keys to be packed into a smaller footprint by utilizing both horizontal and vertical dimensions simultaneously
2Area of stationary object
If compact keyboard design is implemented in single-space parking meters, then device size is reduced, but power consumption increases
Solution Approach 1:
The system implements periodic scanning of the keyboard matrix rather than continuous monitoring, where rows and columns are sequentially activated and scanned at intervals, reducing overall power consumption while maintaining responsive detection capability
Solution Approach 2:
The keyboard controller is extracted as a separate dedicated component from the main parking meter controller, allowing the keyboard scanning and detection functions to be independently optimized for low power operation while the main controller remains in sleep mode during idle periods
3Adaptability or versatility
If SPI keyboard module is integrated into single-space parking meters, then adaptability is improved, but device complexity increases
Solution Approach 1:
The SPI keyboard module implements a universal interface that can accommodate multiple keyboard layouts and configurations through software programming, allowing the same hardware to serve different functional requirements without adding physical complexity
Solution Approach 2:
The SPI bus serves as an intermediary communication interface between the keyboard controller and the main parking meter controller, providing a standardized protocol that simplifies integration while allowing flexible keyboard configurations through software layers
Data Source
AI summary
A serial peripheral interface (SPI) keyboard module for a parking meter comprises a plurality of key switches and at least one controller configured to detect a key press, determine a predetermined indicator associated with the pressed key and transmit the indicator to a keyboard interface of the parking meter. The SPI keyboard module provides a low power keyboard module that can be easily adapted to provide different keyboards or layouts without requiring significant changes to the parking meter electronics.