…I wanted to satisfy one of my persistent self-stabilizing-flying-thing itches: how to pass control inputs from a handheld radio to the flying thing in question without having it process several consecutive servo pulse lengths. For the most common & simplest Arduino-compatible balancing algorithms, this limits the maximum control update frequency to 50hz, since the microcontroller has to actually measure 10 milliseconds of pulse commands (for, say, up to 5 or 6 channels) out of every 20 milliseconds. The remaining time is often taken up by software floating point multiplication and division.
The reason it takes so much of the loop time is because the abomination that is Arduino’s pulseIn() command. It’s a “busy wait” loop that sits and increments a counter while the pulse is being detected. It’s neither interrupt based nor uses the hardware timers (the loop is timed empirically). So while taking in a servo pulsewidth, the microcontroller can literally do nothing else. A little inefficient, in my mind.
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