I connected the GND and the Vcc of the module with GND and the 5V-pin of the arduino. I tried connecting the signal pin with D2 of the arduino with and without a 10k pull up resistor. With the resistor, the signal on D2 stays at hi. Without the resistor the signal shows the behaviour seen in my attachment. The modules datasheet
clearly states a supply voltage range from 1.2 V to 5 V, so there should be no overloading. The datasheet also states a maximum ripple of 10 mVeff. Maybe thats the problem. Does anyone know the ripple of the 5V supply voltage while arduino is connected to my PCs USB-port?