Hi,
You start switch if is between 5v and the input pin, will require a 10K resistor between the input pin and gnd.
This because the input pin must be held either to gnd or 5V, not left open circuit to pick up switching noise.
sorry I dont have schematic. I use resistors (470ohms) only between arduino pin and tranzistors
Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?
Thanks.. Tom.. 