You can make a security device with an old phone and microrupteur you have to set the phone on speed call first solder 2 wire on the key you set solder microrupteur you can get the microrupteur from microwave or in electric store.
How to make Wireless Rechargeable Mous:ehttps://goo.gl/G1DJ1M
Diy Portable soldering iron : https://goo.gl/rcfpjr
Diy make relay with protection : https://goo.gl/TWgV82
Control your home with your Smartphone : https://goo.gl/qBKFZB
Diy Overhead Camera Mount : https://goo.gl/Mxy4EM
FaceBook : https://goo.gl/UWw3m5