That is correct. I use the SmartThings hub with Rachio irrigation controller and Zooz outdoor motion detectors. I am using SmartThings rather than Amazon Echo because SmartThings routines offer more flexibility primarily related to the ability to turn a zone off after 1 minute. I am using this system to keep the deer off of my roses and it is really the sound that scares them off. They are ususally long gone by the time the water starts spraying. You might also be able to use some security camera systems for motion detection. Most of them are smarter than simple motion detectors and can tell the difference between a human, a car, a dog and a deer which would be helpful to keep from watering the UPS guy. I have not tried any to date. Zooz just redesigned their outdoor motion sensors to make them more waterproof. I have not tried those either but eventually I will have to replace existing sensors. They tend to last a few years if they are exposed to water from rain and irrigation. They are battery powered but the batteries last over 1 year so you aren’t having to always change them.
One trick you are going to want to use on SmartThings is to create a virtual device (I call mine “Deer Security”). Then activate and deactivate your system with the virtual device (like if you hare having a dinner party and don’t want to water your guests). You can use a smart speaker to turn the virtual device on and off and have your motion detector/Rachio check that first before running (If deer security =on and motion detected then run zone 6 for 1 minute). It makes activating and deactivating the system much easier than turning every routine on and off. If you need additional help, contact me. I will be interested to see your experience.
One thing to note, Rachio indicated that they were going allow quickrun duration setting to be remembered after each use rather than defaulting to 3 minutes. That may alter the way you want to write your routines if Rachio actually makes that change. One other thing to note… get a surge protector for your Rachio. I have lost more than one to lighting strike power surges. Fortunately they were under warranty and Racho was good about replacing them.
Hope that helps