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    Hey guys, just messing around getting my shiny new uRADMonitor tied in to my home automation system. Through the web interface in the new firmware you can pull CPM but not uSv/hr, which is fine. But when I convert CPM to uSv/hr based on the 0.0057 conversion factor which is what I can find online for the SBM-20 tube, my uSv/hr readings do not match what pops up on the uRADMonitor website. The conversion factor used seems to be about 0.066 instead. So my question is what is the actual conversion factor for this geiger counter so I can make my home automation system read correct values? Thanks.


    Please use the following as a reference:

    ** uRADMonitor radiation detectors
    ** Version: 	0.1.0
    ** Date: 		January, 2014
    ** License:		LGPL v3
    ** Copyright: 	(C) 2009 - 2015 Radu Motisan, radu.motisan@gmail.com
    ** Description:	Used in the uRADMonitor code to identify various radiation detectors, mostly Geiger tubes
    ** www.pocketmagic.net
    ** This file is a part of "Portable Environmental Monitor" open source project presented on
    ** https://hackaday.io/project/4977-portable-environmental-monitor
    ** This project is free software; you can redistribute it and/or modify
    ** it under the terms of the GNU Lesser General Public License as published
    ** by the Free Software Foundation; either version 3 of the License,
    ** or (at your option) any later version.
    ** This program is distributed in the hope that it will be useful,
    ** but WITHOUT ANY WARRANTY; without even the implied warranty of
    ** GNU Lesser General Public License for more details.
    ** You should have received a copy of the GNU Lesser General Public License
    ** along with this program. If not, see <http://www.gnu.org/licenses/>.
    #include "detectors.h"
    // not more than 10 chars!
    char *aux_detectorName(uint8_t param) {
    	switch (param) {
    		case GEIGER_TUBE_SBM20: 	return "SBM20";
    		case GEIGER_TUBE_SI29BG: 	return "SI29BG";
    		case GEIGER_TUBE_SBM19: 	return "SBM19";
    		case GEIGER_TUBE_LND712: 	return "LND712";
    		case GEIGER_TUBE_STS5: 		return "STS5";
    		case GEIGER_TUBE_SI22G: 	return "SI22G";
    		case GEIGER_TUBE_SI3BG: 	return "SI3BG";
    		case GEIGER_TUBE_SBM21: 	return "SBM21";
    		case GEIGER_TUBE_SBT9: 		return "SBT9";
    		case GEIGER_TUBE_SI1G:  	return "SI1G";
    		default: return "unknown";
    float aux_detectorFactor(uint8_t param) {
    	switch (param) {
    		case GEIGER_TUBE_SBM20: 	return 0.006315;
    		case GEIGER_TUBE_SI29BG: 	return 0.010000;
    		case GEIGER_TUBE_SBM19: 	return 0.001500;
    		case GEIGER_TUBE_STS5: 		return 0.006666;
    		case GEIGER_TUBE_SI22G: 	return 0.001714;
    		case GEIGER_TUBE_SI3BG: 	return 0.631578;
    		case GEIGER_TUBE_SBM21: 	return 0.048000;
    		case GEIGER_TUBE_LND712: 	return 0.005940;
    		case GEIGER_TUBE_SBT9: 		return 0.010900;
    		case GEIGER_TUBE_SI1G:		return 0.006000;
    		default: 0;

    Excellent. Exactly what I was looking for. Props on the new website, by the way. I’m not sure about the green superman shields, but the detailed graphing when you click on a node is top notch!


    Thanks! It is finally functional.
    The shields are clusters of units. The bigger their size, the more units are represented. Click one or zoom in to see individual units.

    The detailed graphing is now done on the client side, you get the local timezone to the data’s time coordinates, but also zooming capabilities and more.


    Hello, Radu!

    I’m building a portable one based on STS-1 (that’s what I had nearby). I already have all the parts, I’m working now to position parts on the PCB
    that suits my case (Gainta 828G-S-BC).

    I know that you have used the same model on your previous prototypes, can you please tell me what factor to include in detectors.cpp? I will add STS1 in detectors.h too (at number 9).

    This particular prototype would not be used online. When I would decide to become part of the community, I will use a tube that would allow uniformity between my measurements and the rest of the network.


    Thanks for understanding the uniformity requirements. The conversion factor for your STS1 is available here:

    The STS1 is identical with the SI1, with a factor of 0.006 . You can directly use the previous code posted above, and the Detectors.cpp file


    Hello and Thank You for this very nice project. I have built my DIY uRADMonitor KIT1 and i’m wondering what is the conversion factor for tube SI-16BG. I did not found any information in internet, only few details.
    I did some calculations, but i’m not sure, so please help me to understand.

    Radiation determine: beta ( > 0.25 MeV) ; gamma soft/hard
    Voltage of start of counting: 280 – 330 V ;
    Operating voltage (recommended): 360 – 440 V;
    Length of flat part of counting curve (plateau): 80 V
    Slope of the counting curve: < 0.12 %/V;
    Natural background: < 0.4 counts/s;
    Maximum radiation: 1*10E5 counts/min;
    Load resistance: > 8 MOhm
    Allowable stray input capacitance: 10 pF
    Working temperature range: -50…+70 C

    Best Regards, LZ1JER, Bulgaria


    0.005 for your tube seems very reasonable, however you would need to test it against a calibrated dosimeter.

    I might do that as well, should I find 2x SI16BG tubes. Do you know any good source for them?


    Thanks for Your reply radhoo, SI16BG is rare tube and I found only one seller in ebay. I will test the device in physics lab soon.


    Hi, I was curious if you had the chance to do the test and if you have any results.


    Hi Radhoo, I did compare uRADmonitor with lab gamma spectrometer. The source of radiation was 60Co. KIT1 with SI16BG tube and HW factor 0.005 show us surprisingly correct readings, even when the source was very close to the dosimeter.


    Some pics with this or more documentation on your experiment would be very helpful.


    Sorry, no experimental data or images, it was just a quick test.


    That is regretful, any chance for a second experiment with more persistent observations?

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