can you hear when someone enters

Hi Eazy. There is no sound emitted from sensor itself as it does not have a speaker, however you will receive a push notification on your phone from the Swann Security app whenever it is triggered. In addition, we sell an indoor siren under model code SWIFI-ISIREN which can be linked to the sensor via the app. The siren will emit your choice of alert or siren type sounds whenever the sensor is triggered. -SD, Swann Team.