diff --git a/src/main.cpp b/src/main.cpp
index 6249282..9d5d230 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -91,6 +91,7 @@ Adafruit_BMP085_Unified bmp = Adafruit_BMP085_Unified(10085);
 DHT dht(DHT22_PIN, DHTTYPE);
 SDS011 sds;
 volatile unsigned long geiger_counts = 0;
+unsigned long geiger_previousMillis;
 unsigned long last_wifi_activity = 0;
 unsigned long last_dhcp = 0;
 IPAddress ip, dns, gateway, subnet;
@@ -169,8 +170,13 @@ void ICACHE_FLASH_ATTR sendValues() {
 
 //  sds.sleep();
 
-  sd.radioactivity = -1;
-  sd.cpm = geigeraverage.getAverage()*10;
+  if (millis() - geiger_previousMillis > 60000) {
+    sd.cpm = geiger_counts * 60000 / (millis() - geiger_previousMillis);
+    geiger_previousMillis = millis();
+    geiger_counts = 0;
+    geigeraverage.addValue(sd.cpm);
+  }
+  //geiger_runningaverage = geigeraverage.getAverage()*10;
   float constexpr own_cpm = OWN_BACKGROUND_CPS * 60;
   sd.radioactivity = (sd.cpm - own_cpm) * CONV_FACTOR;
 
@@ -374,13 +380,6 @@ void ICACHE_RAM_ATTR ISR_geiger_impulse() {
   geiger_counts++;
 }
 
-// will be called every 6 seconds
-void timerCallback(void *pArg) {
-  //DEBUG_MSG("running average counts: %d average: %6.2f\n", geiger_counts, geigeraverage.getAverage());
-  geigeraverage.addValue(geiger_counts);
-  geiger_counts = 0;
-}
-
 
 void setup() {
   #ifdef USERDEBUG
@@ -404,9 +403,6 @@ void setup() {
   attachInterrupt(digitalPinToInterrupt(GEIGER_PIN), ISR_geiger_impulse, FALLING);
 
   geigeraverage.clear();
-  geigeraverage.addValue(2);
-  os_timer_setfn(&Timer1, timerCallback, NULL);
-  os_timer_arm(&Timer1, 6000, true);
 
   DEBUG_MSG("ready.\n"); Serial.flush();
 }