I have changed my interval to 2000, and it takes about second to go back to black when I cover the sensor, so I think the interval setting is set correctly in my system.

Ps. If I remember correctly I also had two lines in the ps listing with reference to timenow, when I tried to troubleshoot the starting problem. One starting with the "sh -c..." start and other with "/sh/bin/...." start. My processes can be found in one of my previous post concerning the stop-killall-start routine.