About pins ...
ok, got first arduino (robotdyn ch340/a 2650) several months ago, , i've been playing ... experimenting .... learning ... tons of googling ... ive used few shields ... i'm struggling feel should easy grasp , i've decided post dilemma here.
i seem struggling inputs , accuracy in reading voltages. see, when set pin input because want read voltage (between 0 , 5 volts of course), behavior of arduino not seem consistent 1 pin next, , want start project require consistency in thing. i'm starting wonder if unit faulty.
when set analog pin such a10 input, start reading pin value without voltage applied it, normal readings in 500 range? when take pin ground, goes 0 (depending on pin), , makes no change @ all. when apply small voltage it, changes, doesn't , again seems depend on pin im using (usually between a10 , a15).
second question: ive noticed when declare int a8, comes out 62 when print serial. got me wondering literal pinouts etc., , in searching, looked @ this link unit, according page, pin 62 ground ... gives?
is there way test thing , inputs make sure functioning properly? kind of uniform thing can aa batter or can apply pins , known value etc.?
thank you,
mike sims
i seem struggling inputs , accuracy in reading voltages. see, when set pin input because want read voltage (between 0 , 5 volts of course), behavior of arduino not seem consistent 1 pin next, , want start project require consistency in thing. i'm starting wonder if unit faulty.
when set analog pin such a10 input, start reading pin value without voltage applied it, normal readings in 500 range? when take pin ground, goes 0 (depending on pin), , makes no change @ all. when apply small voltage it, changes, doesn't , again seems depend on pin im using (usually between a10 , a15).
second question: ive noticed when declare int a8, comes out 62 when print serial. got me wondering literal pinouts etc., , in searching, looked @ this link unit, according page, pin 62 ground ... gives?
is there way test thing , inputs make sure functioning properly? kind of uniform thing can aa batter or can apply pins , known value etc.?
thank you,
mike sims
"when set analog pin such a10 input, start reading pin value without voltage applied it, normal readings in 500 range?"
a floating input pin can on place. try 100k pullup resistor provide steady reading when nothing connected.
use 1k, 5k, 10k pot legs @ gnd , 5v, wiper input pin. should see steady reading values reported @ ~ level/4.88mv.
physical pin numbers not same software mapped pin numbers. header pins d0 , d1 connect chip pin 2 , 3 example.
d62 = a8 = physical pin 89 example.
a floating input pin can on place. try 100k pullup resistor provide steady reading when nothing connected.
use 1k, 5k, 10k pot legs @ gnd , 5v, wiper input pin. should see steady reading values reported @ ~ level/4.88mv.
physical pin numbers not same software mapped pin numbers. header pins d0 , d1 connect chip pin 2 , 3 example.
d62 = a8 = physical pin 89 example.
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