I've got a problem with the ms-20 sensors; they occaisionally toglle on and off for a period of time. Sometimes this happens on powerup; sometimes after they have been in the field and working for a while--the sensor will be triggered and then start to toggle on and off. It doesn't seem to be a bbattery problem, I'm think it may be temperature related. Has anybody else had this experience? Has anyone developed a schematic for this unit?