A multitude of actions can trigger this Vision Z-Wave Wireless Shock Sensor - from knocking, to breaking glass, to opening something. To use, secure your vibration sensor to any flat surface (such as a wall, door, or window). Once a vibration strong enough to pass a certain sensitivity threshold is detected, the device will send a signal and alert you of any vibrations affecting the surface you’ve secured the device to.
I like the washer/dryer example. This could be a cheaper way to monitor this as it is something I always forget to check on.