Simple alarm system with Arduino

original article

   A simple system alarm can be made with Arduino board, a sensor module (sound, PIR, Doppler, etc) and 2 switch or remote control.
   Base schematic is

If use buttons (switches) for control alarmsystem_0.ino is use without change

but is use remote control (singnal in HIGH) must changed in

Also, if sensor is like mine (infrared sensor) sketch is without change

but it easy to change in

for negative logic comand (active in LOW).
    After powered the system, alarm is in stand-by

and after push ON button (or button from remote control), alarm is in waitting mode

If sensor is activated, sound (yellow led in my case) is intermittently powered 10 second or more, depend value from here

   You can see 2 video:

- alarm system

- alarm system (2)

20.04.2019

   I add a new movie with this alarm system using RCWL-0516 Doppler (radar) sensor (this sensor was tested a few time ago an posted at http://nicuflorica.blogspot.com/2018/02/senzor-de-miscare-tip-radar-doppler.html). 

Movie is named alarm system with Doppler sensor

   Default sketch is for power off the alarm system

but you can change to be armed after powered up dthe alarm system