Despite the wide selection of hearing aids that are on sale today, not everyone has the opportunity to purchase them due to their relatively high cost. Since the design of the device is quite simple, radio amateurs can try to make a hearing aid with their own hands from improvised parts. The cost of such a device is reduced significantly, but it is very, very difficult to achieve excellent sound quality, and not everyone succeeds.
How the device works
To make your own hearing aid, you need to have a good idea of how it works and how it works. There are only three main nodes in the device:
- Microphone. Needed in order to pick up sounds. The stronger the microphone, the greater the distance a person can hear. But there is another side of the coin - a strong microphone also picks up a lot of extraneous noise, so you will have to look for the “golden mean”. There are two types of microphones: unidirectional (picking up sound from one direction) and multidirectional. The choice of microphone here depends on what you expect from your hearing aid. If you need it for domestic purposes, it is better to use a multi-directional microphone.
- Amplifier. The hardest and most expensive part of the device. It is a microcircuit, passing through which the sound is first converted into an electrical impulse, then processed, cleaned of extraneous noise, amplified and transmitted further. To assemble a hearing aid with your own hands on a microcircuit, you can buy it in a specialized store (order online) or assemble it yourself from individual parts. The size of the hearing aid itself directly depends on the size of the microcircuit.
- Telephone. The part in which the amplified pulses are again converted into sound vibrations. The purity of the reproduced sound depends on the quality of the phones. To create a hearing aid, you will have to look for very small phones that will stick well in the ear canal, but not squeeze too much of the ear tissue, since usually you have to wear the device for a long time, almost all day. Craftsmen often use phones from old mobile phones.
But not everything is as simple as it seems at first glance. The biggest problem is that the design of the microcircuit itself is very complex and that is why good models on sale are expensive. Achieving excellent sound quality in a compact size is possible only with an ultra-precise selection and correct installation of all elements of the hearing aid.
Features and secrets
A diagram for a hearing aid with your own hands is drawn up independently or selected from what can be found on the Internet. It should take into account the required output sound power, the level of noise suppression and the possibility of individual adjustment. In addition to the basic elements for the manufacture of a hearing aid, it is necessary to select:
- the body in which the main elements will be located;
- batteries (usually these are button or finger-type batteries);
- connecting wires that connect the hearing aid to the earmold.
When making a pocket or garment device, it is best to design the microphone so that the microphone is located in the earmold. If you place it in the body of the device, then there will be too much extraneous noise from the clothes themselves, which is very difficult to get rid of.
The clarity and quality of the sound is highly dependent on the correct relative positioning of the microphone and headphone speaker.
They should be strictly perpendicular and as close as possible. Otherwise, a "feedback" effect is created, which greatly disturbs the user.
It is advisable to install at least the simplest three-channel equalizer into the device case. With it, the user will be able to normally adjust the sound timbre and tune the device to the optimal sound mode for himself. Also, a volume control is simply needed, which will allow, if necessary, to lower the sound level at the output.
We see that there are many ways to make a hearing aid at home with your own hands. Success depends on the skill of the manufacturer and technical capabilities. But if you are not good at electronics, you are unlikely to get a really high-quality model. And if the sound is bad, it can further impair hearing. After all, the effect that a medium-power phone has on the eardrum is comparable to the roar of an airplane. Therefore, if you are not confident in your own abilities, it is better to buy an inexpensive but high-quality ready-made hearing aid.
