Geiger Kit - GK-mini

Overview:

The GK-mini is a smaller version of the GK-B5 kit, with fewer components. Its unique features are:

  • Small size. The GK-mini is about the same size as 2x16 display and fits under it.

  • The processor is based on an Arduino compatible "Pro-mini" which is socketed.

  • Faster to assemble. Fewer solder points then the GK-B5. (~139 pads vs. ~227 pads)

  • Less expensive than the GK-B5.

  • Has the same software features as the GK-B5.

Differences between the GK-mini and GK-B5:

There are three main differences in the architecture between the GK-mini and the GK-B5 series. They are:

  • The microprocessor is used to provide the oscillator for the high voltage circuit.

  • The HV pot is read by the microprocessor. HV is adjustable up to ~880V.

  • The microprocessor is also used to provide the "click" and flash the LED.

This means that the GK-mini is dependent on the microprocessor for the generation of the HV as well as the "click" and LED flash.

In comparison, the GK-B5, handles these functions through the hardware. There are certain advantages to the GK-B5's more modular approach. Mainly that the software has only one job to do - count and display events from the tube.

On the other hand the GK-mini is smaller, has fewer parts and is faster to assemble. I had some initial concerns about the microprocessor's ability to handle the additional functions, so I did tests. The counting loop was tested by replacing the GM tube with an external signal of 1kHz (60,000 CPM) from my scope. This gave readings of 59,993 CPM which is about perfect. With a GM tube and a hot source, readings of 85,000 CPM were obtained. Using a pulse generator I got over 250,000 CPM before the display would no longer refresh. Not something you'd like to encounter for real.

While the GK-mini will not reach the maximum counts of the GK-B5 (> 3,000,000 CPM) the GK-mini should suffice for conditions normally encountered.

Build Instructions, User Guide and Software:

See the GK-mini Downloads page for links to the appropriate Build Instructions and User Guide for your kit.

What's included / Availability

  • The GK-Mini kit will contain all parts needed to build out PCB board including an Arduino compatible "Pro-mini".

  • The mini-remote, and a blue/white 2x16 LCD is also provided.

  • The GM tube is not included.

  • A case, power source, and buttons and switches are also not provided.

  • A USB to serial adapter is needed if you want to interface the kit with a PC.

  • The GK-mini is available for purchase on the Buy the Kit page.

THIS DEVICE AND IT'S MEASUREMENTS IS NOT INTENDED TO GUIDE ACTIONS TO TAKE, OR NOT TO TAKE,

REGARDING EXPOSURE TO RADIATION. THE GEIGER KIT AND IT'S SOFTWARE ARE FOR EDUCATIONAL PURPOSES ONLY.

DO NOT RELY ON THEM IN HAZARDOUS SITUATIONS!