Yes, Alexa can turn on your security system if it is compatible. SimpliSafe, for example, is a security system that works with Alexa. You can use your Amazon Echo or the Alexa app on your phone to control SimpliSafe. However, please note that Alexa integration with SimpliSafe is limited and cannot control your cameras. In addition to Alexa, SimpliSafe also works with other popular smart home devices like Amazon and Google smart speakers and August smart locks. By connecting your security system to Alexa, you can easily control and monitor your home security using voice commands.