Portable Terminal Power-Up Sequence with Key Debounce
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Solution Overview
Problem
Existing methods for powering up portable terminals are too slow due to a predetermined time delay, which wastes energy and reduces battery life, while also being prone to inadvertent activation from key bounces.
Innovation Solution
A method that starts the software program before the initial predetermined time interval ends, with a shorter second interval to debounce key bounces and a third interval to ensure continuous key depression, automatically powering off if the key is released, allowing earlier terminal usage without unnecessary energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a predetermined time interval longer than 1 second is used to avoid inadvertent key contact, then false activation is reduced, but the terminal startup time becomes too long for the user
Solution Approach 1:
The software program starts running before the first predetermined time interval (Δ1) has fully elapsed. Specifically, the program starts after a second time interval (Δ2, longer than 5 ms and shorter than 100 ms) has elapsed, which is sufficient to cause key bounces to cease. This preliminary action allows the initialization process to begin earlier while still maintaining reliability by checking that the key remains depressed until the end of Δ1
Solution Approach 2:
The patent implements a dynamic, multi-stage timing mechanism with three distinct time intervals (Δ2, Δ3, and Δ1) rather than a single static delay. The system transitions through different operational states: initial debounce waiting (Δ2), continuous monitoring phase (Δ3), and final confirmation phase (Δ1). This dynamic approach optimizes both responsiveness and reliability at different stages of the startup process
2Reliability
If the terminal waits for the full predetermined time interval before starting the software program, then key bounce is avoided, but energy is wasted during the waiting period
Solution Approach 1:
The software program is initiated in advance, after a较短 second time interval (Δ2) that is sufficient to allow key bounces to cease but much shorter than the full first time interval (Δ1). This preliminary action reduces the duration of the powered-on state while maintaining reliability through continuous key position monitoring during the remaining time (Δ3) until Δ1 elapses
Solution Approach 2:
The system continuously monitors the key position during the third time interval (Δ3) and checks at the end of the first time interval (Δ1) whether the key is still in the active position. This feedback mechanism ensures that even though the software starts early, the terminal will power down automatically if the key is released, preventing energy waste from inadvertent activation
Data Source
AI summary
A method of powering up a portable terminal, which automatically executes a software program when powered on, the terminal having a manually operated power-up key, wherein the method comprises the step of: a) at the beginning, moving (in 32) the key from an idle position in which the terminal is powered off to an active position in which the terminal is powered up, then b) before a first predetermined time interval (Δ1) has elapsed since the beginning of step a), starting (in 36) to run the software program on the terminal, the first time interval being long enough to check that the key has not been inadvertently moved, then c) when the first time interval elapsed, if the key is still in the active position, continuing (in 42) to run the software program, else powering down the terminal (in 40).