Arduino Security Alarm with Backup Battery Circuit

In this project I designed a security alarm for my cousin’s office. It will detect movement from door. I use SIM800L in curcuit. When ypu typed “Kapa” the system will be locked and if detect any movement form door it sends SMS to our phone. Also I use backup battery circuit for any power cut. Thanks to this guy for very simple and effective circuit !.(https://www.instructables.com/id/Arduino-Mains-Failure-Battery-Backup-Circuit/) Yeah it’s a very small project to make in weekend.