A microphone that picks up a specific voice in a crowd

Two hundred and fifty one participating students from 15 universities across the UAE and 70 projects. The 8th IEEE UAe Student Day 2013 competition was tough by any standard so the joy and euphoria experienced by Mohammad Luai A. Hammadih,⟡Abdulla AlShehhi,⟡Mohammad Sami Zitouni and⟡Saif Alkindi, is completely understandable. After all, they walked away with the first prize in the Senior Design Project Competition. The four, Electrical &Engineering students from Khalifa University, are flush with the triumph. Their project, a Microphone Array for Audio Surveillance & Conferencing, impressed the judges with its intricate enginnering principles and purpose. Dr. Luis Weruaga, Associate Professor at Khalifa University, Sharjah Campus, and project Advisor, says of the winning team’s work, ““The students had the faith and belief to pursue an idea that seems apparently simple but is extremely difficult to assimilate even at the graduate level, and to follow a tight working plan as precise as a Swiss watch.”

Dr Nazar Ali, Associate Professor at Khalifa University, Sharjah Campus, and also Project Advisor, says, “Their presence and aura on the day of the competition convinced the jury, audience, and even competitors of the merit of the idea.”

Education asks the winning quartet how they achieved the accolades.

How did you conceptualise the project?

The project is a multidisciplinary work between analog hardware design, digital hardware, computer programming, and mathematical analysis. Every project member was working on a specific part of the system, developing and testing each part individually. Only in the integration phase did all parts came together resulting in the final prototype. This final outcome showed an incredible accuracy between the simulations (what we designed) and the final performance of the system (what we actually built).

What are the electrical engineering principles you used for the microphone project?

The microphone array is based on the principles of beamforming, which refers to the ability to capture electronically the sound only from a certain direction while suppressing sounds from other undesired directions. Moreover, the sound recording from several directions independently by one single device is perfectly possible. These engineering principles have been used for quite some time in electronically-steered RADAR systems. The extension to the acoustic field is, however, more challenging because acoustic signals such as music or speech are “broadband”. Sound signals are made up of sinusoidal waves within a broad range of frequencies. These acoustic waves are captured by each microphone in the array at different times and finally combined in a digital signal processor by means of complex numerical algorithms. This advanced processing creates the “beamforming” effect, that is, only acoustic waves coming from a specific angle are coherently combined while those from other angles are suppressed.

How will this microphone device help in making things better?

The microphone system can be useful in meetings with many participants, as it would replace the individual microphone for each participant with a single central device that can “listen” to each one individually. The final prototype has a size of 10 centimeters plus, which means it can be used on any meeting room table or in a room. Another useful application is remote acoustic surveillance: in the same way that security cameras are used to watch and track people in conflictive areas, this system can be used to record conversations taking place in a specific location. As the system is fully electronic and has no movable or mechanical parts, the acoustic surveillance is unobtrusive and unnoticeable by the target.

Any challenges during the project?

As mentioned already, the microphone array project is a combination of hardware components (electret microphones, preamplifier circuits), sophisticated mathematical theory (beamforming and signal processing), the programming of a multichannel audio DSP board. All these things combined are completely novel in our university. A major challenge in this project was how to integrate these three main parts in order to achieve our purpose taking into consideration that these are new topics for us. To overcome these challenges, we designed, simulated and tested the three main parts separately in order to make sure of its validity. Then we spent hours testing the overall system and found minor problems and solved them. Our team work helped us meet the challenges.

How did you pick the microphone project?

Actually, each professor proposed several projects at the beginning of the senior year and we were looking for a project where we can design and implement real engineering system with a good level of complexity that combine hardware and software skills and it can be developed to become a useful product in vital applications such as (conferencing, security), thus we found that the microphone array project satisfies our desire for selecting the project.

Accordingly, we met with the associated project advisors (Dr. Luis and Dr. Nazar) and decided to take the project with them.

What is the unique thing about your project? How will it make a difference?

It uses an advanced technique to do its objective which is new and very efficient. Additionally, our project has not been done before in the UAE or the Middle East. It will make a difference in the field of conferencing since we will be able to record everything that has been said in a conference or meeting with crisp clarity. The device is also beneficial for security use to perform acoustic tracking in indoor or outdoor scenarios.

What are the most exciting developments in the field of electrical engineering today?

There are so many! The research and development in semiconductors, which results in smaller and more powerful integrated circuits, is one of them. This continuous increase in the digital computing power will allow during the next decades for incredible systems and applications impossible to imagine today.

Why are you so passionate about this field (electrical engineering)?

In electrical engineering, we learn how things work such as the electrical machines and electronic devices that are everywhere even in our pockets! Everything in the world is now about technology, and our field the most related one to technology which can open the door in front of us to contribute in improving the world we are living in to achieve better future.

According to you, what has been the most amazing invention in the world?

The production and storage of electricity.

What would you four like to invent, if you had all the resources at hand?

An artificial brain.