A simple and handy system to measure vibration-induced displacement is developed. It consists of three accelerometers, a processor and dry battery and stored in a small watertight box. Measured acceleration is transformed into displacement. If relationship between displacement and stress at point of interest is known, one can also obtain stress range histogram to be used for fatigue assessment of the structures. The system works for four weeks with dry battery and is suitable to measure long term displacement and stress range histograms. Calibration and laboratory tests of the system, where the system is attached full-scale overhead sign structure, is carried out.
