Vibhear, as assistive hearing device, ensures safeness for people with hearing loss, when hearing aid is not used or is not working.

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World Health Organization (WHO) estimates that about 5% of world population have disabling hearing loss. Those who use hearing aids in some occasions need to take them off which lead to reduced alertness and increased risk to personal safety.
The Vibhear bracelet allows users to feel vibrations that correspond to surrounding warning sounds in case when hearing aid is not in use or is not working. Additionally, users can set up the alarm, that will trigger vibration at the expected time (for wakening up, or as remainder).

Why use Vibhear bracelet?

Our little friend Kosta (6 years old) wears cochlear implant. He was born with almost complete hearing loss and ability to hear only very strong sounds. Cochlear implant makes possible for him to hear even weak sounds and at the same time enables him developing the speech and communicating with his surroundings.

One evening, my wife and I were in the visit to Kosta’s family staying late at night. While we were leaving home, we all cheerfully laughed in the hallway, forgetting that Kosta was already in the bed sleeping. It worried us that we will wake him up, but Kosta’s parents explained that this is not possible, as he does not wear the external unit of cochlear implant during the night, so he cannot hear almost anything while sleeping. 

And then it struck us how frightening must be to go to bed every night without being able to hear anything (phone ringing, door bell, someone calling your name, or in case of any sudden danger occurs).  And how difficult must be for his parents to ensure  waking him up by direct contact every morning, especially when they are at work, and soon he will start to go to school. All this put us to thinking what can be alternative solution for this situation.

We have also found out that people wearing cochlear implant usually take off external unit every night because of many reasons. For some it is uncomfortable wearing it during the night. For some it is the possibility of cable damage (costing approx. 200 euros per piece). There are also people feeling exhausted of all sounds they are receiving during the day and they need a rest. Also there are other situations when hearing aid is taken off and when people wearing them are left in the silence, without possibility to react on warning sounds (for example, while swimming as hearing aids are not waterproof, or while waiting for fix in case of damage).

What is Vibhear bracelet?

So, the idea came up to create the Vibhear bracelet, as assistive hearing device and additional support for people wearing any kind of hearing aid in the moments when they are not wearing them, or they are not working.

The Vibhear bracelet is sensitive to surrounding sounds and when the sound volume exceeds a predefined threshold in decibels (dB), it vibrates and warns the user. The idea is that user can define volume of the sounds they consider warning so they can set up the bracelet to vibrate at certain volume level. If any kind of warning sound occurs in the immediate vicinity (fire alarm is triggered, explosion occurs or someone loudly shouts), the bracelet will vibrate. This will allow user to be aware of his surrounding in moments while not wearing hearing aid, and to react appropriately.

For everyday usage, it is possible to set up vibration alarm as wake up alarm or remainder. Vibration triggered by alarm or sound can be stopped by pressing main bracelet button. Time, alarm indicator and battery status indicator are shown within the small display.

Who needs Vibhear?

The Vibhear bracelet can be beneficial to Kosta and all other children and adults who need cochlear implant or any other hearing aid at the time when they are not used or are not working. 

World Health Organization (WHO) estimates that there are about 360 million people worldwide with disabling hearing loss, out of which 28 million are children. The majority has level of moderate to profound hearing loss, which requires wearing any kind of hearing aid in order to enable social and every day functionality for these people. Many occasions that require taking off hearing aid, lead to reduced alertness and increased risk to personal safety. 

Vibhear bracelet could benefit in all these situations by improving awareness of warning sounds and safety of the user at the same time.


World health organization issued hearing aid guide which we plan to use as guidelines for further bracelet development.

Adobe Portable Document Format - 291.96 kB - 08/29/2017 at 08:04


  • 1 × Arduino Nano Based on the ATmega328
  • 1 × Vibration Motor Similar to ROB-08449
  • 1 × Microphone Breakout Board LM393 with electret condenser microphone
  • 1 × RTC Board Based on DS1307
  • 1 × Fabric Strap

View all 10 components

  • Vibhear prototype

    Srdjan Pavlovic05/04/2018 at 14:46 0 comments

    We have finally made first bracelet prototype :)

    You can watch video, which shows how bracelet reacts on surrounding sound input.

  • Assembling of bracelet

    Ivkovic Bojan12/26/2017 at 13:39 0 comments

    The bracelet is finally assembled and tested. Soldering of Cortex presented a new experience for us :) Fortunately, we didn`t experience any major problems.

    Read more »

  • Data Acquisition, Signal Processing and Pattern Recognition

    Srdjan Pavlovic08/29/2017 at 08:01 0 comments

    During bracelet usage, the microphone records all sounds that exceed the predefined threshold, so it is necessary to filter those sounds which present potential threat to a user. For example threat sounds can be: 

    • Fire alarm 
    • Care horn 
    • Police, ambulance and firefighter siren 
    • Fire and smoke alarm (within building) 
    • Dog growling and barking.

    In the Matlab software package, we performed a spectral analysis of the sound that produces smoke alarm. Furthermore, we plan to do an analysis of all signals that are of interest to bracelet users ie, signals that can pose a danger / threat to the user. When we collect and analyze all results, we will decide which type and how we will implement the digital filter.

    As an additional bracelet functionality we are considering to perform classification of the signal, which would enable the bracelet to "recognize" the sound and initiate different vibration intensity/duration for different signals. For example, if a bracelet detects a police siren, it can vibrate constantly and thus increase certainty that user will not miss the warning.

  • MVP Block Diagram

    Ivkovic Bojan08/28/2017 at 08:21 0 comments

    Bracelet block diagram shows all necessary HW modules. Since we have defined the necessary HW modules, we use FINDCHIPS for search of needed components like MCP73831.

    Read more »

  • Panic Mode / Testing Audio Microphone

    Ivkovic Bojan08/27/2017 at 12:37 0 comments

    Given that vibration test has passed successfully, the next phase is adding an audio microphone. 

    Automatic vibration of the bracelet, initiated by surrounding sound, has application both during daytime activities and while its owner sleeps. For example, if Kosta temporary do not use hearing aid while playing outside, the bracelet can warn him to the sound of a car horn, to the noise of roadworks or to the loud calling of his parents.

    Read more »

  • Wake Me Up / Vibration Testing

    Srdjan Pavlovic08/25/2017 at 09:07 0 comments

    At the very beginning we wanted to see if it is possible and what it is like to be woken up by a vibration. In order to validate the idea, we used a Mi Band bracelet (activity tracker), whose vibrations can be triggered by the alarm. Team members have chosen me (Srdjan) as our test subject. 

    As Mi Band bracelet successfully woke me up, we have tried the same with Kosta. Unfortunately as Kosta has deeper sleep (both as a child and as hearing loss person) vibration was not strong enough to wake him up few days in a row. 

    We realized that Vibhear bracelet would need stronger vibration.

    Read more »

View all 6 project logs

  • 1
    Necessary steps to building MVP

    These instructions will describe development of minimum viable product (MVP). We start from scratch so any tip or advance is more than welcome !

    For testing different use cases, we have used Arudino, but for MVP we plan to make custom made PCBs. At the same time, we will also design several 3D models and the final design will mostly depend on the dimensions of PCBs.

  • 2
    Choosing Microcontroller

    The heart and brain of the bracelet is microcontroller , thus the first step is choosing the most suitable development system. Although Microchip has high-quality series of microcontrollers, we have decided to use cortex platform. Previous experience has shown us that programming is simple for MBED platform and that it has possibility of connecting with Keil debugger so we will use it for Vibhear. The idea is to make the prototype with MBED and afterwards to move programmed controller to a custom PCB

    Well, let's start :)

    Which cortex to choose from this boards

    We need some affordable model which is also strong enough to support digital signal processing. If there is a need we will compile a program for a stronger version of the controller.
    Board MicrocontrollerPackage & CorePrice                    Stock
    NUCLEO-L152RESTM32L152RET6 in LQFP64
    ARM®32-bit Cortex®-M3
    8.3$568 In Stock
    NUCLEO-F446RE STM32F446RET6 in LQFP64 package ARM®32-bit Cortex®-M4
    CPU with FPU
    14.9$766 In Stock
    NUCLEO-F042K6STM32F042K6T6 in LQFP32 package RM®32-bit Cortex®-M0 CPU2.8$3182 In Stock
    NUCLEO-F030R8STM32F030R8T6 in LQFP64 packageARM®32-bit Cortex®-M0 CPU2.1$
    Temporarily Out of Stock
    NUCLEO-F401RESTM32F401RET6 in LQFP64 packageARM®32-bit Cortex®-M4 CPU with FPU5.9$Temporarily Out of Stock

    M0 sounds like the best choice. We already have two development systems NUCLEO-F401RE with M4 cortex so we will use them and in the meantime, we will order a couple of M0 development plates. The priority is that the cortex does not increase bracelet production costs too much and that the stock is stable. 

    Next, we will continue with power supply...

  • 3
    Working on PCB

    PCB design is completed. I'm using Altium/Circuit Maker. Take a look at snapshot . This is double layer PCB with component in each side and dimension 35x35mm.

    We will use this board to test Cortex M0+ and other modules.  

View all 3 instructions

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