Hearing aid "headphones" for conductive deafness

Fu Hao 　　Generally, hearing aids are worn on the ears and may not work for some deaf patients. The 'headphones' introduced here are bitten in the mouth and listened through the teeth ("bone conduction" method). It can enable some patients to hear sounds again. Production principle Sound waves are transmitted through the external auditory canal to the tympanic membrane and auditory ossicles, stimulating the cochlea Internal auditory receptors, this conduction path is called "air conduction". In addition, a wave of vibration can also be transmitted to the inner ear through the vibration of the bones of the head (such as mastoids and teeth), stimulating the auditory receptors, which is called "bone conduction". Some patients with conductive deafness cannot hear sounds through "air conduction", but they can hear sounds through "bone conduction". The "headphones" introduced here are made based on this principle. After inserting the earphone jack of the hearing aid, the sound current is converted into mechanical vibration through the coil in the magnetic field. If you bite the "earphone" in your mouth, you can hear the sound through "bone conduction". Connect the "earphone" to the radio, etc. You can also enjoy music. Production method: Two "earphones" are made using the ring magnets in ordinary 8Ω earphones and the cylindrical magnets in small speakers. Figure 1(a) is a "headphone" made with ring magnets, and the coil is made of 0.07. mm enameled wire is directly wound around the screw, with a round plastic piece padded at both ends. The number of coils is based on the size of the space inside the ring magnet, and the "earphone" handle uses a wooden handle (or hard plastic handle). When the screw is screwed into the water handle. , don't be too tight, as too tight will reduce the volume. Figure 1(b) is an "earphone" made of cylindrical magnetic steel. The coil is wound around a slightly smaller diameter at the front end of the "earphone" handle, about 1cm long, and the diameter of the enameled wire is 0.1. mm, densely wound with 4 layers, the cylindrical magnet is placed at the top, and the outside is covered with a suitable plastic sleeve for fixation, which can also be fixed with tape.