Alexa Guard is ready to turn your Echo into a home security device

It can also integrate with your existing security system.

It took more than half a year to come to fruition, but Amazon's Alexa Guard is finally a reality. Starting today, Americans can use their Echo speakers as home security devices -- tell Alexa "I'm leaving" and your devices will alert you through phone notifications if they hear glass breaking, a CO2 alarm or a smoke alarm. You can use a Drop In call to verify if there's anything wrong, and send alerts to ADT or Amazon's own Ring if you have professional security services through either brand.

You can likewise take advantage of Away Lighting to make it seem like you're at home, with machine learning flicking lights on or off based on its understanding of typical customer behavior. Not surprisingly, your voice can arm or disarm ADT (Control or Pulse) and Ring systems.

The feature is free if you have an Echo device, and only requires delving into the Guard section in settings to get started. You might not get it right away as it's gradually rolling out.

This isn't going to replace a full-fledged security system or dedicated security cameras. If an intruder is quiet or breaks in through a door, you're still in trouble. However, it could offer some peace of mind if you can't justify the usual costs of home security or want to augment your existing safeguards. This also shows how smart speakers can be put to work beyond voice commands. While there are privacy concerns with having the devices activate for sounds other than a keyword, they could prove useful for detecting all kinds of unusual audio cues in the right circumstances.