The following modifications will allow the Mighty Ohm Geiger counter board to operate on 5 volts instead of 3 volts.  This modification is required in order to make the serial output of the geiger board compatible with the Arduino Uno.
 
 Modify as follows:
 
 1. Change R6 to 1K ohm
 2. Change R11 to 330 Ohms
 
 After making the resistor changes above the next step is wiring the Arduino to the geiger board.
 
 Power & Ground
 1. Connect +5v from Arduino to Geiger PCB Pulse J6 pin 1.
 2. Connect GND from Arduino to Geiger PCB Pulse J6 pin 3
 
 Serial Data
 1. Connect Arduino D5 to Geiger PCB Serial J7 pin 5