Prison house monitoring device and system and method

The invention provides a prison house monitoring device and a system and a method. The prison house monitoring device includes one or more nanometer generators and a central processing circuit. Signal output ends of the nanometer generator are connected with the central processing circuit. When the nanometer generators are subjected to an instantaneous pressure, the signal output ends output a first electrical signal to the central processing circuit. When the nanometer generators are subjected to a variable pressure, the signal output ends output a second electrical signal to the central processing circuit. When the variable pressure which the nanometer generators are subjected to disappears, the signal output ends output a third electrical signal to the central processing circuit. The central processing circuit sends out an alarm signal according to whether the first electrical signal, the second electrical signal and/or the third electrical signal are/is received. The prison house monitoring device and system use characteristics of positive and negative voltages output by the nanometer generator to carry out an alarm prompt timely on abnormity of criminals on beds so that preventative measures are taken and an objective of monitoring the criminals is achieved.