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Phil Gillaspy

Updated February 19, 2017 - Updated ICD document to clarify interpretation of 16-bit CPS and CPM data.

Updated February 3, 2017 - Updated ICD document with latest definition of GMC-3xx non-volatile memory storage of configuration data.

Updated December 29, 2016 - Updated README.txt file. Added explanation about changing GMC geiger
counter model's vendor id and product id which are used in the 51-gqgmc.rules file. Changed 51-gqgmc.rules file to provide instruction on how to discover vendor id and product id.

Updated: September 1, 2016 - Added zip file to download all files at once. Updated README.txt file to
refer to zip file for dowloading files.

Updated: February 24, 2016 - Added the following GQ GMC commands to the driver: power on, reboot, factory reset, set date/time (all in single command), and get date/time (all in single command).

Updated: February 12, 2016 - Added data logging to file to the GUI program, gqgmc_gui. Data recorded each minute with time of day and day of year timestamp.

Updated: May 7, 2015 - Added UDEV rules file, 51-gqgmc.rules to create symbolic link to device /dev/gqgmc from /dev/ttyUSB*.

Updated: March 5, 2013 - Added the individual commands to set the year, month, day, hours, minutes, seconds.

GQGMC is a user level driver for interfacing a Linux host to GQ Electronic's GMC-3xx (e.g., GMC-300) geiger-muller counter. Written in C++, the driver provides an interface method for each of the capabilities of the GMC-3xx. The capabilities of the GMC-3xx are described in the GQ-GMC-ICD.odt (or doc) document. Perhaps of greatest use, the GMC-3xx can provide the Counts per Minute upon command from the Linux host. The GMC-3xx also has configuration data and an internal history buffer all of which are read/write-able from the Linux host. Further documentation is embedded in the source software, principally, gqgmc.hh and Any user is expected to read the documentation embedded in the source code files which has complete discussions of the GMC-300's data and operation, in other words, the documentation and the code are integrated.

A sample console based program is provided for excercising the GMC-3xx. A sample Qt based GUI program is also provided, although it functions only as a simple data logging plot of the counts per minute. A Makefile is also provided for building the console or GUI programs. The sample programs are only compiled for 64-bit x86 Linux under Ubuntu 11.10, 12.04, 14.04, and 16.04, however, it is compilable for 32-bit Linux. See the README.txt file for changes needed to compile/link for 32-bit Linux.

The GUI program, gqgmc_gui, plots data on a scrolling graph of twenty minutes width. Data is plotted every ten seconds. In addition to graphing, the GUI program logs data to a file once a minute with time of day and date timestamps. See the README.txt file for running gqgmc_gui with arguments.

User feedback would be appreciated either by writing a review or emailing me at

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