diff --git a/ampel-firmware/co2_sensor.cpp b/ampel-firmware/co2_sensor.cpp
index 51cfa3dcb3d07926889fdce6e64deeb6e88b4203..11db5c3dad0fb2097a4574a3d300af6115722666 100644
--- a/ampel-firmware/co2_sensor.cpp
+++ b/ampel-firmware/co2_sensor.cpp
@@ -296,7 +296,7 @@ namespace sensor {
       Serial.print(F("Setting Measurement Interval to : "));
       Serial.print(timestep);
       Serial.println(F("s."));
-      sensor::scd30.setMeasurementInterval(timestep);
+      scd30.setMeasurementInterval(timestep);
       config::measurement_timestep = timestep;
       led_effects::showKITTWheel(color::green, 1);
     }
@@ -308,7 +308,7 @@ namespace sensor {
       config::co2_calibration_level = calibrationLevel;
       Serial.print(config::co2_calibration_level);
       Serial.println(F(" ppm."));
-      sensor::startCalibrationProcess();
+      startCalibrationProcess();
     }
   }