Measuring the Bow Pressing Force in a Real Violin Performance

In the last few years, many high quality and realistic violin synthesizers appeared. But the quality of the resulting sound is sometimes poorer than promised due to the lack of musical information provided to the system. It is very difficult for composers to deduce and include information like “bow speed”, “pressing force” or “fingering” to a MIDI file while real violinists base their musicality on these parameters, among others. The aim of this work is to present a system to measure the pressing force that the violinist applies to the violin string through the bow. It is based on two strain gages attached to the frog and the tip of the bow that modify the behavior of an electronic circuit. The output of this circuit is attached to a microcontroller to process the data and converts it to MIDI format. This paper will show the details of the system and the calibration.