Electret condenser microphone as a traditional Chinese medicine arterial pulse sensor

Arterial pulse signal reading by a therapist in Traditional Chinese Medicine (TCM) requires considerable experience and thoroughness. The interpretation resulted by the therapist is very subjective. The objectivity of the device can be achieved by increasing the accuracy and the consistency of the reading in the range of 1-2 Hz. An electret condenser microphone (ECM) can be used as a pulse sensor in such device. This study reveals that ECM performs a number of advantages such as small-sized and inexpensive. Unfortunately, this ECM also picks up mechanical noises during direct contact with the subject. This study proposed soft silicon rubber as a medium between subjects and ECM. The technique was designed to enhance the mechanical coupling between the ECM and the source signal without affecting the signal source. The results show that the ECM could measure the signal of 0.5-10 Hz with the average accuracy of 99,47%.