Quick help for wire connection

hi guys,

can ask me have @ wire connection please. want synchronize solenoid (12v dc) 2 servos (standard small servos), , controlled momentarily contact push button. example, when press button, solenoid turned on whilst 2 servos start move simultaneously. have written code (hopefully works), not sure wire connections:

q1). have watched many videos , connect servos arduino directly without resistors,  1 added capacitor on voltage supply. first question, have use resistor ? if yes, how should connect resistor , how work out value of resistor required ?  , said never use arduino power servo directly, using external batteries (6v) ?

q2). know how connect arduino servo (without resistor) picture attached shown (multiple servos). in circuit have push button (like picture attached: push button) requires +5v power supply (on arduino) connected push button. if want arduino power both servo , push button together, can link +5v (on arduino) common positive ground on breadboard, gnd (next +5v on arduino) common negative ground on breadboard, connect positive side of servo  , 1 pin button the  common positive ground respectively, whilst ground of servo , gnd (on digital pin side on arduino)  connected common negative ground on breadboard ? ok ?

q3). if did connection above, how can connect 12v dc power supply breadboard ? because assume neither servo nor arduino can take 12v dc ? example, can connect 12v dc power supply common grounds on breadboard arduino , servos connected ?

thank !

regards, jeff

hi jeff

quote

and said never use arduino power servo directly, using external batteries (6v) ?

especially when using multiple servos, think putting load on arduino onboard voltage regulator.  i'm sure servo expert comment on this.

quote

so if want arduino power both servo , push button together, can link +5v (on arduino) common positive ground on breadboard, gnd (next +5v on arduino) common negative ground on breadboard, connect positive side of servo  , 1 pin button the  common positive ground respectively, whilst ground of servo , gnd (on digital pin side on arduino)  connected common negative ground on breadboard ?

the common things called "busses" rather "grounds".  latter term risks confusion gnd.  apart major (!) question of whether power servos arduino, using busses connect multiple things indeed designed for.  don't need second arduino gnd connection, "gnd (on digital pin side on arduino) ".  first 1 mention enough.

it save external pullup resistor, though, if connect switch between digital pin , gnd.  enable internal pullup resistor in arduino, this:

code: [select]

pinmode(9, input_pullup); // substitute pin number

and code need low result of digitalread indicates switch pressed.

regards

ray

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