Figure 3 from LASER based security system using wireless sensor network and GPRS/GSM technology for inland aquaculture in Bangladesh | Semantic Scholar
laser-alarm-arduino | Laser Alarm - Laser Alarm Security System Using Arduino
Arduino and Gsm based laser security system "Intruder Alert message"
How to build an optical/light barrier with the Arduino, the Keyes laser module (KY-008) and a laser receiver/detector module - Michael Schoeffler
ARDUINO laser tripwire burglar alarm
Laser security alarm project using Arduino - Gadgetronicx