conversion factor corrected

mkgeiger · Mar 7, 2019 · 2e08d08 · 2e08d08
1 parent 5c83052
commit 2e08d08
Show file tree

Hide file tree

Showing 2 changed files with 5 additions and 5 deletions.
diff --git a/GeigerCounter/GeigerCounter.ino b/GeigerCounter/GeigerCounter.ino
@@ -16,9 +16,9 @@
 #define AP_NAME "geiger_counter"
 #define AP_TIMEOUT 60
 
-// Geiger Mueller tube parameterization (see datasheet of SBM-20)
-// gamma sensivity for Radium224: 29cps = 1740cpm ≙ 1mR/h = 10μS/h ->  1cpm ≙ 0.0057μS/h
-#define SBM20_FACTOR  ((double)0.0057)
+// Geiger Mueller tube parameterization (see manufacturer of radiation kits: http://www.libelium.com/wireless_sensor_networks_to_control_radiation_levels_geiger_counters/)
+// gamma sensivity: 60cps = 3600cpm ≙ 1mR/h = 10μS/h ->  1cpm ≙ 0.00277μS/h
+#define SBM20_FACTOR  ((double)0.00277)
 #define NBR_GMTUBES   2
 #define TUBE_FACTOR   (SBM20_FACTOR / (double)NBR_GMTUBES)
 
@@ -552,7 +552,7 @@ void loop()
 	// setup the google chart options here
 	client.println("    var options = {");
 	client.println("      width: 700, height: 600,");
-	if (lastcSvTmp < 1.0)
+  if (lastcSvTmp < 1.0)
 	{
 		client.println("      min: 0, max: 1,");
 		client.println("      greenFrom: 0, greenTo: .25,");

diff --git a/README.md b/README.md
@@ -66,7 +66,7 @@ First install the [Arduino IDE](https://www.arduino.cc/en/main/software). Under
 
 ### GM-tube parameterization
 
-The GM-tube conversion factor can be adapted in the source code when other GM-tubes are used. In the datasheet of the SBM-20 tube we find following: Gamma Sensivity Ra226 = 29 cps/mR/h. In other words: 29 cps are equivalent to 1 mR/h. Or 1740 cpm are equivalent to 10μS/h. Or 1 cpm is equivalent to 0.0057 μS/h. This conversion factor has to be divided by the number of used GM-tubes.
+The GM-tube conversion factor can be adapted in the source code when other GM-tubes are used. At [Libellum](http://www.libelium.com/wireless_sensor_networks_to_control_radiation_levels_geiger_counters/) (the company that manufactures radiation kits) declares for the SBM-20 tube a convertion factor of 0.00277, which is equivalent to a gamma sensivity of 60 cps/mR/h. In other words: 60 cps are equivalent to 1 mR/h. Or 3600 cpm are equivalent to 10μS/h. Or 1 cpm is equivalent to 0.00277 μS/h. This conversion factor has to be divided by the number of used GM-tubes.
 
 ### NTP client