Embedded Files
KEY TAKE AWAY POINTS:
Mind the 2+2 pins, and the internal connections
Usually as a simple digital signal input ("digital read pin [ ]")
Mind "floating input" and pull-up/down
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Tactile Button
Tactile Button
Popular tactile button for hobbies
Floating Inputs & Pull-Up/Down
Floating Inputs & Pull-Up/Down
Floating Pin❓ - Random Input❗
Floating Pin❓ - Random Input❗
"digital read pin [ ]" reads in the input from pin (voltage), which must be safely managed. Idle input from pin (voltage) is floating, unless it's pulled up/down.
Pull Up/Down by Software (internal)
Pull Up/Down by Software (internal)
Use software to activate built-in pull up/down resistor, not always available.
Pull Up/Down by Hardware (external)
Pull Up/Down by Hardware (external)
Pull it up/down by a pulling-resistor wired externally.
Bouncing Inputs & De-bouncing Techniques
Bouncing Inputs & De-bouncing Techniques
Bouncing Issue
Bouncing Issue
A natural mechanical jitter phenomenon, for almost all contactors, including switch/button, or even just direct alligator clips contacts.
When closing the contacts, the contact bounces around a bit, going closed, open, closed, open, closed, etc. It's kind of like dropping a ball - it bounces before finally sitting still on the ground.
De-bouncing Techniques
De-bouncing Techniques
Hardware based approach
Software based approach
Just add a delay (“debouncing window”) after the initial detection, purposefully ignore the bouncing period
Micro:bit built-in button A/B input has 54ms denouncing period
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