DIY Bone Conduction Hearing Device

Let's get started with this innovative tutorial in which you will learn to create your own bone conduction hearing device that lets you listen without using your ears. You may have encountered such a situation when listening to music with ear buds or external headphones; while listening to loud music with headphones, someone greets you behind you, or there is a motorized horn to warn you, but you are completely unaware of it. That is not only embarrassing but also dangerous in some cases. The most significant advantage of bone conduction is that it does not block your ears; your ears remain open, allowing you to hear warning sounds from the outside world.

Components Required

• 27mm Piezo Transducer x2
• PAM8403 Audio Amplifier
• 3.5mm Audio Jack
• 9V Battery
• 7805 Voltage Regulator
• Connecting wires

How does Bone Conduction Work?

Let's break down the inner and outer ear concepts. Normally, we hear sounds because vibrations in the air cause vibrations on our eardrum, which is referred to as the outer ear. These vibrations are transmitted to the cochlea, which sends a signal to our brain. The cochlea is a part of the inner ear.
As the cochlea is bone-bound It can pick up vibrations from any part of the skull. In this case, the skull serves as our means of conduction. We can hear these sounds if we place a vibrating device on our head, behind our ears, or anywhere it makes good contact with the bone.

What is PAM8403 Module?

The PAM8403 is an Amplifier Board that can be powered by a simple 5V input and drive two 3W + 3W stereo speakers. It is an excellent choice for anyone looking for a Class-D stereo audio amplifier with a small board footprint. This Amplifier enables the user to reproduce high-quality audio from a stereo input.

If you want to add wireless features to your project you can buy our Bluetooth amplifier Module from here.

To amplify the signal an amplifier is required. So, PAM8403 is a good fit for this project. Although it is a stereo amplifier. Here, It is used in mono mode. The sound quality improved after the addition of this amplifier. We can hear just like we would with regular earphones. The only drawback is that there is no bass. However, given that we are only creating a sample project to test bone conduction, it is excellent. With this amplifier, the volume is so high that we can hear from a distance using our outer ear as well. However, if you place this Piezo anywhere on your head and plug your ears, you will be able to hear music without using your ears. Just like MAGIC.

Circuit Diagram