Last things to do for this project are:

• Select and attach power supply to be connected directly to the line
• Make the system activate the alarm
• Add a GSM or GPRS module in order to communicate with mobile phones

In this post I will briefly show you and describe what I did for the first two points. I will then write a special post for the third and last part which is a bit more complicated, at least for me.

The power supply

After a lot of research on the web I finally found a power supply for my purpose: here is the link on AliExpress. It’s a AC DC 220 V 9V 6W.

Here are the specifications:

Driving the alarm with a relay

In order to drive the alarm horn I decided to use a relay: a songle srd-05vdc-sl-c. This converts the signal of the alarm pin into a driving power for the horn itself as it needs 12V while the Arduino output pins are 5V.

I found a tutorial on instructables, here is the link.