wiring the pi - Raspberry Pi Forums
hello evereyone,
planning on wiring button's pi.
planning on direct connection between 3.3v pin->button->gpio, see lot of people putting resitors in parrallel ground.
because saftey (will direct connection wil fry pi?) or high low sensing?
planning on wiring button's pi.
planning on direct connection between 3.3v pin->button->gpio, see lot of people putting resitors in parrallel ground.
because saftey (will direct connection wil fry pi?) or high low sensing?
people use resistors both safety , high/low sensing.
when pin defined input , not connected (switch off , no resistor), input @ level. "float". takes tiny bit of current make level go high enough register high, stray electrical fields radio waves, magnetic fields, static electricity, make appear if switch has been pressed.
connecting high value resistor between input signal , ground/0v, pulling input low slightly, no input register low. when switch connects input 3.3v pull input high more strength resistor pulling low, input read high.
on safety aspect, connecting resistor between gpio pin , switch/resistor joint prevent current flowing if pin accidentally defined output. imagine happen poor pi if pin set output, turned low (0v) , switch pressed , connects 3.3v? current limited safe amount, pi safe.
when pin defined input , not connected (switch off , no resistor), input @ level. "float". takes tiny bit of current make level go high enough register high, stray electrical fields radio waves, magnetic fields, static electricity, make appear if switch has been pressed.
connecting high value resistor between input signal , ground/0v, pulling input low slightly, no input register low. when switch connects input 3.3v pull input high more strength resistor pulling low, input read high.
on safety aspect, connecting resistor between gpio pin , switch/resistor joint prevent current flowing if pin accidentally defined output. imagine happen poor pi if pin set output, turned low (0v) , switch pressed , connects 3.3v? current limited safe amount, pi safe.
raspberrypi
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