In our motion-sensing devices (e.g. CPR4, CIP, HumanFinder and CiWater), accelerometers sense the device's self-movement to reduce false alerts when the sensor is moved and to alert the operator that the sensor is moved, shown in yellow in indicators and graphs saudemasculina.pt.
These self-movement sensors are sensitive to very small movements such as when the device is moved, a knock on the wall the sensor is attached to, or a door closing. It is discovered that the vibration sensors can be useful as a complement to the radar during surveillance to detect environmental vibrations. In CiMonA there is an option to show a vibration bar together with a radar motion bar. Below is an example of the vibration view from drop tests.
In the drop-test video the "vibrations" where quite substantial. In applications where more subtle vibrations want to be detected, such as a knock from a survivor or steps from an intruder, we have an option, a 100 times more sensitive sensor than our standard self-motion-detector. This built-in hyper-sensitive vibration sensor is close to the sensitivity of a bulkier geophone. With this compact multi-sensor accelerometer/radar-solution, advanced signal processing and data fusion we can achieve a sensor system capable of classifying different movements more accurately.