摘要 |
The movement of a surface is detected by a movement sensor comprising a mercury switch (32, figure 1c). When movement is detected a transmitter sends a movement signal a remote receiver 3. The system can be used to detect movement of a swimming pool cover 20 where a remote user is alerted to cover movement (e.g. due to person in water) by transmission of the movement signal to a remote receiver 3(e.g. attached to the user's belt). The system can be used to detect movement of other surfaces such as a vehicle 3, a door (figure 9) etc. (e.g. to alert the owner of theft). The receiver may alert the user if the transmitter power is low or is the receiver is out of range. |