I have a simple setup - Motion detector sends a signal which sets off the remote chime when a car pulls into the driveway.

Eagle Eye Outdoor Motion Sensor - MS14A
Transceiver Module - TM751
Remote Chime - SC546A

The motion detector is installed on a tree branch 12 feet high facing down into a driveway. I get false alarms sometimes during the day and also no alarms sometimes during the night when a car pulls into the driveway.

Can anyone suggest how I should diagnose this?

Thanks...RN