Tremor analysis in human or animal model plays a fundamental role for understanding the physiopathology of human disorders and to test new pharmacological treatments. Mechatronic systems for automatic and quantitative behavioural analysis are now of current use for neuroscientists to improve the results of their research. Most of these devices are portable and need to be used out of engineering labs by personnel with no technical expertise and without specific equipment. The calibration of the devices, that should be performed before each experimental session, is a typical issue to be faced. This paper deals with a new calibration method that is fast, simple and doesn't need other external measurement systems. It is based on the parallel use of an accelerometer and an optical sensor. The two signals are processed and compared to obtain the final calibration curve of the device.