Pictured below is a device we recently made for use within a bird hide. When motion is detected inside the hide (via a small KC7783R PIR sensor module), a small MP3 player is turned on to play an educational soundtrack.

Because the length of the track may be changed, the device is fitted with a button which enables the number of minutes that the MP3 player is powered after motion detection to be adjusted so that the whole track is played, but no power is wasted by not leaving the MP3 powered when the track has played (since this is a solar PV powered set up).

If you need any type of motion sensing device or timer, please email neil@reuk.co.uk with details of your requirements.