Solar Powered Hearing Aid Details

ComCare Model GLW: A Hearing Aid for Developing Countries


Environments filled with dust and water, isolated locales, annual incomes as low as $200, and a clientele unaccustomed to technology are factors incompatible with traditional hearing aids. Yet these factors apply to millions upon millions of hearing impaired people in the developing world.

hearing aidTo answer this need, ComCare has developed a rugged, lowcost hearing instrument, the GLW. This instrument's case is made of high strength molded ABS resin. The entire design is shock resistant and impervious to dirt and water. The GLW is the size of a credit card and approximately a half inch thick. It weighs less than 2.5 oz. (70g).

The battery replacement problem has been solved by using rechargeable batteries, along with a solar panel built into the front of the instrument. When the batteries are charged, the GLW continues to work even in the dark. Typically, the user needs to recharge the instrument in direct sunlight, about one hour a day.

The GLW is usually worn in a pocket or at the waist, much like a "pager". A high strength stainless steel clip, which is supplied attached to the aid, may be used to secure the GLW to clothing. ComCare provides a high strength cord, custom built for the Model GLW, to connect the module to the receiver (earpiece).

The wearer of the GLW needs to operate only a single control, and easy-to-grip aluminum knob that clicks to one of six positions. Position "0" is off, while positions "1" through "5" provide consistent and accurate volume settings. An easy to read dial shows the switch setting.

The GLW has two internal adjustments, accessible only to the dispenser. By adjusting the internal gain control and the internal bass cut control, a wide range of hearing losses can be fitted. To further increase the success of fittings, the GLW is available in two models. They differ only in the output power characteristics.

The GLW was conceived in Nepal and designed in the U.S. Preliminary field trials were held in Nepal and in the Dominican Republic. Since late 1996 the GLW has been assembled and dispensed in Mexico.

The GLW has been successfully fitted to patients ranging in age from 2 to 97.

Mechanical and Operational Specifications

  • Body worn type with internally sealed battery and builtin solar cell for
  • Size:2.16 in. wide x 2.60 in. high x 0.75 in. thick
    (5.5 cm wide x 6.6 cm high x 1.9 cm thick)
  • Weight: Less than 2.5 oz. (70 gm), not including cord and receiver
  • Case material: high impact strength ABS polymer
  • Clip: stainless steel wire, 0.063" (1.6 mm) diameter
  • Solar panel protection: internal shock resistant mounting plus clear plastic
    pane covering panel
  • Cord: custom twisted threewire with moldedinplace connectors. High
    strength cordage. Lengths: 22" (56 cm), 27" (69 cm), and 32" (81 cm)
    Volume/onoff switch: 6 position, 30 degree index; service life greater
    than 25,000 changes
  • Knob: machined aluminum, knurled sides. Suitable for use by persons with
    limited dexterity. Weather resistant dial indicates "0" for off and volume
    settings "1" through "5".
  • Water resistance: Submergible under 4 inches of water for 1 minute without permanent damage. (Excluding receiver. The microphone screen needs to dry
    after submersion.)
  • Operating time from full charge without recharging: typically two weeks or
  • Recommended charging: daily, for one hour in midday sun
    (in tropical and semitropical latitudes)

Acoustic Specifications

Two versions are available:

  • GLW-1, linear output power stage.
  • GLW-2, limited maximum power output stage. This version is particularly beneficial for patients who have recruitment.

Both versions have two internal adjustments, accessibly only to the dispenser. By adjusting the internal gain control and the internal bass cut control, a wide range of hearing losses can be fitted.

GLW-1 GLW-1 Response Curve (40KB download)

  • Maximum Output .............·. 130 dB @ 1800 Hz (typical)
  • SSPL 90 (ANSI Average) ·................·. 127 dB (typical)
  • Peak Gain ····..............· 56 dB +/- 2 dB @ 3750 Hz
  • Full On Gain (ANSI Average) ·............... 50 dB +/- 2 dB
  • Total Harmonic Distortion
  • (Full On Gain, 65 dB input, 1600 Hz) ····.·· < 1%

GLW-2 GLW-2 Response Curve (40KB download)

  • Maximum Output ..............· 120 dB @ 1600 Hz (typical)
  • SSPL 90 (ANSI Average) ··...................117 dB (typical)
  • Peak Gain ··.................·· 54 dB +/- 2 dB @ 3550 Hz
  • ANSI Response Curve Gain ·................· 41 dB +/- 2 dB
  • Total Harmonic Distortion
  • (ANSI Response Gain, 65 dB input, 1600 Hz) .·..... < 1%

GLW-1 and GLW-2

  • Master gain adjustment range (1600 Hz)..........· >12dB
  • Bass cut adjustment range (250 Hz) ..............·. >16 dB
  • External volume ·..........·...5 positions, 3.5 dB per step
  • Equivalent Input Noise ..............···.·.·· <= 28 dB

Ordering Information

Each GLW includes the electronic module with attached stainless steel clip, high strength cord, normal response receiver, and brush for cleaning the microphone grill.

  • Price: U.S. $125
  • Please specify Model GLW-1 or GLW-2. The two models may be combined for quantity discounts.
  • Please specify cord length(s). Available in 22" (56 cm), 27" (69 cm), and 32" (81 cm).
  • A Dispenser's Toolkit, for making the internal gain and bass cut adjustments, is included with every order. Additional Dispenser's Toolkits may be ordered for U.S. $10 each.

Acceptable payment is check or money order payable in U.S. dollars. Payment in full is required before delivery.

Custom earmolds are not provided with the instrument.

The ComCare aid is not registered for use in the United States. ComCare's GLW aids are stocked and shipped from Tennessee, U.S.A.

GLW instruments may be returned for refund less a $10 per aid restocking fee per aid within 60 days of purchase. Purchaser is responsible for return shipping.

You may place your order by phoning the ComCare office, 210-317-9998. Or, by contacting us via email or letter (contact us by following this link).