alarm
alert
background
burglar
camera
care
control
crime
danger
detector
different
electric
electronic
emergency
equipment
flat
grey
home
house
intruder
items
many
modern
monitoring
motion
movement
object
prevention
privacy
property
protection
risk
safety
security
sensor
set
signal
siren
sound
spy
surveillance
system
technology
thief
threat
tools
video
warning
watch