A data collection apparatus includes a sensing unit for attaching to a structure or live subject for sensing a parameter of the structure or live subject. The sensing unit includes a sensor, a data storage device, and a transmitting device. The data storage device is for storing data from the sensor. The apparatus also includes a control unit that is separable from the sensing unit. The control unit includes a data receiving device and a second data storage device different from said first storage device. The data receiving device is to receive data transmitted from the data sensing unit. The second data storage device is for storing the data received from the sensing unit. The apparatus also includes a triggering device for modifying the storing of data being stored to the first data storage device or for initiating transmission of data from the sensing unit to the control unit. The triggering device is controlled by a real time change in information about the structure or live subject.