EVAL-CN0536-ARDZ is a low-power Geiger counter in an Arduino form factor shield that can run on a 3V to 5V system supply. It has a novel architecture for its ultra-low-power, high voltage generator that is robust and adjustable across a wide voltage range allowing the user to set the sensitivity of the board accordingly. This reference circuit design is compatible with most of the Geiger-Muller tube sensors available in the market today with a voltage rating between 280V to 500V. Moreover, it uses a hysteric voltage regulation scheme by controlling the power supplied to the board oscillator minimizing the overall current consumption. It has a configurable voltage reference for its output allowing the board to safely translate the Geiger pulses to the logic level of the microcontroller. Lastly, it has audio and visual indicators to qualitatively alert the user as the radiation levels increase.