Using push-button switches without pullup/pulldown resistors?

Other Hardware Sensors
1

Is it possible for me to use push-button switches without pullup/pulldown resistors? I may have made a mistake wiring push-button switches with pullup/pulldown resistors and the Pololu motor controllers don't work properly with switches. The motor controllers work without switches.

The motor controllers are shown in Pololu - Dual VNH3SP30 Motor Driver Carrier MD03A
The switches are wired like the schematic shown in http://arduino.cc/en/Tutorial/Button

#include <Servo.h> 
Servo servo01;
Servo servo02;
Servo servo03;
Servo servo04;
int InA1 = 22;
int InB1 = 23;
int PWM1 = 9;
int InA2 = 24;
int InB2 = 25;
int PWM2 = 10;
int InA3 = 26;
int InB3 = 27;
int PWM3 = 11;
int InA4 = 28;
int InB4 = 29;
int PWM4 = 12;
int switch01 = 38;
int switch02 = 39;
int switch03 = 40;
int switch04 = 41;
int switch05 = 42;
int switch06 = 43;
int switch07 = 44;
int switch08 = 45;
int switch09 = 46;
int switch10 = 47;
int switchstate01 = 0;
int switchstate02 = 0;
int switchstate03 = 0;
int switchstate04 = 0;
int switchstate05 = 0;
int switchstate06 = 0;
int switchstate07 = 0;
int switchstate08 = 0;
int switchstate09 = 0;
int switchstate10 = 0;
void setup() 
{
  pinMode(InA1,OUTPUT);
  pinMode(InB1,OUTPUT);
  pinMode(PWM1,OUTPUT);
  pinMode(InA2,OUTPUT);
  pinMode(InB2,OUTPUT);
  pinMode(PWM2,OUTPUT);
  pinMode(InA3,OUTPUT);
  pinMode(InB3,OUTPUT);
  pinMode(PWM3,OUTPUT);
  pinMode(InA4,OUTPUT);
  pinMode(InB4,OUTPUT);
  pinMode(PWM4,OUTPUT);
  pinMode(switch01,INPUT);
  pinMode(switch02,INPUT);
  pinMode(switch03,INPUT);
  pinMode(switch04,INPUT);
  pinMode(switch05,INPUT);
  pinMode(switch06,INPUT);
  pinMode(switch07,INPUT);
  pinMode(switch08,INPUT);
  pinMode(switch09,INPUT);
  pinMode(switch10,INPUT);
  servo01.attach(5);
  servo02.attach(6);
  servo03.attach(7);
  servo04.attach(8);
  servo01.writeMicroseconds(1500);
  servo02.writeMicroseconds(1500);
  servo03.writeMicroseconds(1500);
  servo04.writeMicroseconds(1500);
  delay(1000);
}
void loop()
{
  switchstate01 = digitalRead(switch01);
  switchstate02 = digitalRead(switch02);
  switchstate03 = digitalRead(switch03);
  switchstate04 = digitalRead(switch04);
  switchstate05 = digitalRead(switch05);
  switchstate06 = digitalRead(switch06);
  switchstate07 = digitalRead(switch07);
  switchstate08 = digitalRead(switch08);
  switchstate09 = digitalRead(switch09);
  switchstate10 = digitalRead(switch10);
  if (switchstate01 == HIGH)
  {
    digitalWrite(InA1,HIGH);
    digitalWrite(InB1,LOW);
    analogWrite(PWM1,255);
  }
  if (switchstate02 == HIGH)
  {
    digitalWrite(InA1,LOW);
    digitalWrite(InB1,HIGH);
    analogWrite(PWM1,255);
  }
  if (switchstate01 == LOW && switchstate02 == LOW)
  {
    analogWrite(PWM1,0);
  }
  if (switchstate03 == HIGH)
  {
    digitalWrite(InA2,HIGH);
    digitalWrite(InB2,LOW);
    analogWrite(PWM2,255);
  }
  if (switchstate04 == HIGH)
  {
    digitalWrite(InA2,LOW);
    digitalWrite(InB2,HIGH);
    analogWrite(PWM2,255);
  }
  if (switchstate03 == LOW && switchstate04 == LOW)
  {
    analogWrite(PWM2,0);
  }
  if (switchstate05 == HIGH)
  {
    digitalWrite(InA3,HIGH);
    digitalWrite(InB3,LOW);
    analogWrite(PWM3,255);
  }
  if (switchstate06 == HIGH)
  {
    digitalWrite(InA3,LOW);
    digitalWrite(InB3,HIGH);
    analogWrite(PWM3,255);
  }
  if (switchstate05 == LOW && switchstate06 == LOW)
  {
    analogWrite(PWM3,0);
  }
  if (switchstate07 == HIGH)
  {
    digitalWrite(InA4,HIGH);
    digitalWrite(InB4,LOW);
    analogWrite(PWM4,255);
  }
  if (switchstate08 == HIGH)
  {
    digitalWrite(InA4,LOW);
    digitalWrite(InB4,HIGH);
    analogWrite(PWM4,255);
  }
  if (switchstate07 == LOW && switchstate08 == LOW)
  {
    analogWrite(PWM4,0);
  }
  if (switchstate09 == HIGH) 
  {     
    servo01.writeMicroseconds(500);
    servo02.writeMicroseconds(2500);
    servo03.writeMicroseconds(500);
    servo04.writeMicroseconds(2500);
  } 
  if (switchstate10 == HIGH) 
  {     
    servo01.writeMicroseconds(2500);
    servo02.writeMicroseconds(500);
    servo03.writeMicroseconds(2500);
    servo04.writeMicroseconds(500);
  } 
  if (switchstate09 == LOW && switchstate10 == LOW)
  {
    servo01.writeMicroseconds(1500);
    servo02.writeMicroseconds(1500);
    servo03.writeMicroseconds(1500);
    servo04.writeMicroseconds(1500);
  }
}
2

Change these from

pinMode(switch01,INPUT);
to
pinMode(switch01,INPUT_PULLUP);

or
pinMode(switch01,INPUT);
digitalWrite(switch, HIGH);

either will enable the internal pullup resister.
If the switch is open, they will read as High.
If the switch is closed to Gnd, they willl read as Low.

3

Does Arduino Mega 2560 R3 board have pullup resistors on I/O pins? I made a test circuit on Arduino Uno R3 board and it worked. I think the circuit doesn't work on Arduino Mega 2560 R3 board. I connected the switch from GND to I/O pin 38 on Arduino Mega board and nothing happened after inserting serial.println lines.

4

Data sheet says they do:
"All port pins have individually selectable pull-up resistors with a supply-voltage invariant resistance."

Did you change your setup code to enable them?

5

I changed the code from

pinMode(switch01,INPUT);

to

pinMode(switch01,INPUT_PULLUP);

I think that I may have made wiring errors. I tested the circuit with two buttons and a servo on Arduino Uno board and it worked.

6

Cool.

7

I got the circuit working on Arduino Mega 2560 R3 board with 10 push-button switches and five servos.

8

Cool. Buttons with internals pullups only?

9

Buttons with internals pullups only? Yes.