diff --git a/src/main.cpp b/src/main.cpp
index b7ead25..496dc59 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -118,6 +118,28 @@ unsigned long rtcMillis() {
   return ((uint64_t)(rtc_t*(uint64_t)cal) >> 12)/1000;
 }
 
+void fpm_wakup_cb_func1(void) {
+  //gpio_pin_wakeup_disable();
+  //ESP.wdtFeed();
+  //wifi_fpm_do_wakeup();
+  wifi_fpm_close();
+  //geiger_counts++;
+}
+
+void lightsleep() {
+  ESP.wdtFeed();
+  wifi_station_disconnect();
+  wifi_set_opmode(NULL_MODE);
+  wifi_fpm_set_sleep_type(LIGHT_SLEEP_T);
+  wifi_fpm_open(); // Enables force sleep
+  GPIO_DIS_OUTPUT(GPIO_ID_PIN(GEIGER_PIN));
+  PIN_FUNC_SELECT(PERIPHS_IO_MUX_MTCK_U,FUNC_GPIO13); // PIN_FUNC_SELECT(PERIPHS_IO_MUX_MTDI_U,FUNC_GPIO13);
+  gpio_pin_wakeup_enable(GPIO_ID_PIN(GEIGER_PIN), GPIO_PIN_INTR_LOLEVEL);
+  wifi_fpm_set_wakeup_cb(fpm_wakup_cb_func1);
+  wifi_fpm_do_sleep(0xFFFFFFF); // Sleep for longest possible time
+  //delay(1);
+}
+
 void ICACHE_FLASH_ATTR sendValues() {
   sd.temperature = dht.readTemperature();
   sd.humidity = dht.readHumidity();