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Should I use 1K resister for switch on arduino?

Hi all,

I know this is basic question but not sure if I did it right? I use the switch as picture shown below. Do I need to connect 1K ohm in digital pin in order to get digitalread() "1" or "0" in result?

The result I got looks funny. I have 3 of those switchs in MEGA board. The result seems delay or sometime it trigger the pin beside it as well. It's a bit hard to debug unstable result. Hope anyone could help me. Thanks!

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If you wire this switch to ground so that it connects one pin to ground when activated and disconnects it when not activated then you can use the internal pull ups


#define switch (pin# goes here)

void setup(){

pinMode(switch, INPUT);

digitalWrite(switch, HIGH);



Now the switch should read "1" when not activated and "0" when activated. 

Interesting! it works~~~ thanks!!