There is a bug in “Light Turn On Motion”, which is a shortcut SmartApp in Lights & Switches (where it appears as “Turn on when there is motion”). The bug affects dimmers that are being turned on by motion and then turned off again after x minutes of no motion. If you enter the motion detection area just as the lights are turning off from no motion, or shortly thereafter, they won’t turn back on. In fact, they won’t turn back on until after motion stops again. This creates a dead spot (in motion activation) around the time that they turn off. This is definitely a bug, it’s reproducible, is fixable, and has been reported to ST support.
I wrote a simple SmartApp called “Motion Controlled Lighting” that replicates the functionality of “Light Turn On Motion”. This app provides pretty much the same functionality, but without the bug. With this app, if you enter the motion detection area just as the lights are turning off, they will immediately come back on, as they should. There is one additional feature, the ability to select extra motion sensors that must be inactive for the “turn off when no motion” function. If you use the separate “Light Turn Off Motion” shortcut SmartApp in Lights & Switches (where it appears as “Turn off when there is no motion”) together with “Motion Controlled Lighting”, the dead spot will still exist, hence the additional feature.
The app is available on my Github:
“Motion Controlled Lighting” is a new version of “Lights Turn On Motion”, which is a shortcut SmartApp found in Lights & Switches. The latter has a bug affecting motion turning on the lights correctly around the time that they turn off. “Motion Controlled Lighting” fixes that bug while providing the same functionality (with a little bit more). As with the original shortcut app, this new app allows you to mix switches and dimmers, to specify a dimmer level for the dimmers (0 to 99), and to restrict the app by time, days, and mode.