This is my upgrade to existing security system. After the project, my car automatically make a phone call to my mobile number when ever security siren turn on.
All you need....
YOUR CAR MUST HAVE ANY SECURITY SYSTEM TO DO THIS UPGRADE !!!!!
1. Old mobile phone with fixed dialing facility. (working)
2. timer relay (from ebey)
4. few meters of circuit wires
when the security system turns on... it supply continuous 12v current to siren. I bypass the siren power wire and use it to trigger the timer relay..... Then relay connect the fixed dialing key connectors of the phone..... and phone dial the number you want.
1. Identify the siren power wire or any other wire that supply 12v when siren turns on
2. use it as relay power positive
3. connect the relay power negative to vehicle body
4. solder the two touch area carefully (without connecting each together) with two wires
5. connect this two wires (4th step) to relay
6. Assign the fixed dial number to above key (4th step key)
I use earphone jack and jack base to connect the phone and relay. Then it is easy to unplug the phone for charging. Also I set phone "screen always on" in-order to use fixed dialing at any time.