Connecting a 12v Siren connecting Mega 2560


I want to connect sound a siren at the end of my arduino based game, the siren takes a 12v battery . I don't have any real wiring or electronic circuit experience but after doing some investigations I have decided the best way(also the simpliest) would be to connect a 5volt relay to the arduino with the battery and siren connected and then just set the pin connected to the Arduino to HIGH when I want the siren to sound.

Couple of things, is the this the right way to do it? if so can some maybe suggest the correct wiring, the relay I have seen has 5 pins and is available form Maplin Also as I will be powering the Arduino using a 9v battery and only the siren using the 12, if I kill the power to the Arduino will this drop the connection in the relay or will it stay HIGH?

Thanks in advance for any help


Hi Dexter,

Take a look at the Arduino Power section of the http://ArduinoInfo.Info WIKI here:

Relay boards are cheap... and easy to use.