A method of measuring vibration on an operational device. The method includes providing an operational device with a control unit and a vibration sensor having a three axis accelerometer, a digital signal processor, and a communications transceiver. The digital signal processor takes the raw vibration data for each axis of the three axis accelerometer and applies a weighting function to the vibration data for each individual axis. Then stress level data associated with the vehicle operator is used to calculate the instantaneous contributions of the filtered data to the stress level data of the operator to determine instantaneous stress level data that has accumulated over a fixed time interval. After the fixed time interval, the digital signal processor calculates an increase of the stress level of the operator during the time interval to create stress data that is transmitted through a communications transceiver for display.