Step 1: Schematic
The schematic for this project is shown above.
It consists of three switches:
-one to connect to a 9V power supply
-one to switch the backlight of the LCD on and off
-a magnetic switch (called a reed switch) which closes each time the wheel completes one full rotation.
The Parallex LCD is designed to connect to the arduino using only three pins (ignore the labels and the other pins int his schematic). One to 5V, one to ground, and a third to serial out (TX)- on the arduino, serial out is digital pin 1.
10kOhm resistors are connected to the reed and backlight switches to prevent excess current between 5V and ground (you should never directly connect 5V and ground on the arduino!)