Low Cost Hearing Impairment Screener Equipment
A great proportion of the human population suffers from hearing loss. Hearing loss may be a measure of the shift in the sensory system compared to a normal ear for the detection of a tone. It is a problem that affects people of all ages all over the world. An audiometer is feasible only in downtown areas and highly specialized hospitals. In India, 70% of the population is rural, and the doctors have to travel long distances for attending to these masses. So, keeping this in mind, a portable low-cost hearing impairment screener is developed. The equipment includes microcontroller, pure tone generator, attenuation control unit and headphones
Function generator IC is used for pure tone generation of different frequencies. It works on the principle of variable voltage input which is controlled by digital to analog converter. Attenuation controller has digital volume control and contains an inbuilt power amplifier. The volume is controlled by up-down going pulses which in turn are controlled by the microcontroller. LCD is used for displaying the selected frequency and hearing level. Switches are available in the front panel to vary the frequencies and hearing levels. The generated pure tone of desired frequency and hearing level is sent to the headphone on the patient. The feedback from the patient is obtained and is noted in an audiogram. The audiogram shows the level of hearing impairment of the patient.