Multiple Buttons

Projects General Guidance
1

I have 4 buttons that each go to a different input pin.

At this link: https://www.arduino.cc/en/Tutorial/Button ( I can't figure out how to post the image)
there is a wiring schematic.

My question is if I start with that drawing and add a second button from 5v to pin 3 do I need a second resistor or can I wire it through the resistor already in place.

2

You need a R for each pin.

The preferred method is to use an R from 5v to the pin and switch to Gnd. This can be done using a 10k R or be using the internal pull-up R.

Weedpharma

3

Here's that schematic:-

But weedpharma's suggestion is better.
You turn on internal pullups like this:-

pinMode(pin, INPUT_PULLUP);
4

Simple servo control code that uses two buttons.

//zoomkat servo button test 12-29-2011
// Powering a servo from the arduino usually *DOES NOT WORK*.

#include <Servo.h>
int button1 = 4; //button pin, connect to ground to move servo
int press1 = 0;
int button2 = 5; //button pin, connect to ground to move servo
int press2 = 0;
Servo servo1;

void setup()
{
  pinMode(button1, INPUT);
  pinMode(button2, INPUT);
  servo1.attach(7);
  digitalWrite(4, HIGH); //enable pullups to make pin high
  digitalWrite(5, HIGH); //enable pullups to make pin high
}

void loop()
{
  press1 = digitalRead(button1);
  if (press1 == LOW)
  {
    servo1.write(170);
  }    
  
  press2 = digitalRead(button2);
  if (press2 == LOW)
  {
    servo1.write(10);
  }
}