Make sure that in addition to the device handler that you also install and publish the SmartApp on the SmartThings API site online.The SmartApp is what links Simplisafe with SHM. Once installed and published there, goto your SmartThings app on your phone. Head over to the Automation Tab and then SmartApps. Click on “Add a SmartApp” at the bottom.
Scroll to the bottom of the list and select My Apps. From there select Simplisafe Monitor. If you don’t see it, then you didn’t install and publish it correctly online.
Once installed, go into the settings and set things up the way you would like. The only required thing to setup is the first option, “Select alarm system”.
You can also choose other things such as what switches get controlled, although this is just limited to a state for a switch or switches when OFF or ON (armed away or home). After that the SHM and Simplisafe should be working together.
Unfortuately because of the way the individual sensors work with Simplisafe, you will have have direct access to them in SHM. However, you can, using routines, set the SHM state (Off, Armed/Away, Armed/Stay) and that will be reflected in Simplisafe. There is a little bit of a delay with things though.
If you set or disable your alarm in SHM, the real Simplisafe System should be set accordingly within about a minute.
If you set or disable your alarm at the keypad, through the simplisafe app, or simplisafe device in SmartThings, it could take up to 5 minutes for it to be reflected in SHM.