News We solved our problem from last week by buying the "SIM 900 GPRS/GSM Shield for Arduino" for 35.05 CHF. It enables to make calls from the Arduino to another SIM card. Thus the communication between customer and user is enabled. Hardware Testing The motion detector was tested successfully. So the "Hardware Testing" phase is completed. Program Testing We also tested our program that should recognize faces if the motion detector is triggered. The program works but still can be extended. Next Step How to connect the Raspberry Pi with the Arduino that is connected to the GSM shield? So a phone call could be made to the user if the face of the customer could not be recognized. Make a sketch of the hardware case.