Using Arduino Interrupts - Hardware, Pin Change and Timer
Comparing raw pin toggling speed between Arduino platforms. - Toe-to-toe - microforum.cc
The Ultimate Arduino Tutorial - TurboFuture
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5 Position Slide Switch | Toggle Switch Arduino | Arduino Small Switch - 3mm 4mm 5mm 6mm - Aliexpress
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Controling Ports directly for fast digitalRead and digitalWrite, also replace delays with timer to further decrease time of program execution - Programming Questions - Arduino Forum
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