2D Sound Locator

By

Abdulla Al-Ansari

I am working with a team on a device that will use 4 microphones to determine the angle from the viewer a prerecorded sound or frequency and display it on a separate device. The separate device will be an android that will be user friendly. I am tasked with the coding of the Microcontroller that we will be using, which is an Arduino, and designing the enclosure for the device.

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Artifacts

Name Description
Display Audio Processor Interface The design is based on a clone based on a paper , USB-Phone and other sources. The design consists of usb protocol commands from stm32 microcontroller in a low frequency kept on purpose which may be improved in future research on project. The data will come from sound localization device which is also through code of STM32 in form of 2d plane coordinates. The data rate is kept on 576000 bauds per second transmission following Rules of Serial Communication. This may be increased further by testing higher data rates. The data will be sent to a GUI device using usb serial communication protocol with specs defined in validation interface table. Function calls for send/receive commands will be managed by the controller and the interface will provide a bridge between GUI and sound locator device. The device may send commands to choose between real time sound localization and recorded sound localization.   Download
Enclosure The main objective of this block is to provide a firm grip to android phone with a hollow cavity in enclosure fitting in the phone correctly. Furthermore, the controller size is 101.52mm x 53.3mm which is the main space taking equipment after the phone itself. The detailed dimensions of controller can be seen in figure 4a and 4b. The front of enclosure will have phone placement hollow cavity which can be adjusted as per size of the phone with a strap around the phone as shown in figure 2a. A hole of 4mm diameter is placed on one corner in order to provide an opening for the camera. Furthermore, on the back of enclosure as shown in the Figure 2b, there are 4 microphone modules attached to the enclosure which will be done using m3 fasteners. The reason for choosing m3 fasteners is to provide a light weight but efficient grip to the enclosure thus protecting the inner vitals i-e phone and controller. Furthermore, there would be a hole of 3mm diameter below every microphone module from which the connecting wires of microphone would go inside the enclosure. Also, the controller inside the enclosure would be mounted using m3 fasteners at corners and a 0.5inch foam material would be placed below the controller to avoid damage of its soldering and pins. It can be seen in Figure 4a that there are 4 holes for m3 fastener mounting on the Arduino mega board which will be utilized here.   Download
Sound Localization A little background about this project is necessary here to understand this block better. So the project will take sound signals from 4 microphones arranged in an array like 4 corners of square. Also, it is capable of taking sound from a sound file instead of microphones. The analog sound signals would be then processed by first digitizing then apply fast fourier transforms etc and then cleaned data for all 4 microphones would be stored in an integer array. Now once the data is stored, this block comes in practice and it will take data from the array discussed above and apply test expressions to find out the distance of sound from the microphone which is getting the strongest signal. Once the closest microphone is found, the 2nd closest microphone will be found similarly. Now once we get distance of sound from both of these microphones giving positive response to sound being closest, using their mutual distance, the distance and direction of sound can be inferred. The guideline and help over this sound localization was taken from numerous papers primarily this and this where numerous techniques over this topic are discussed. Once the sound is localized, the results are stored in temporary variables and then later on in next block would be transmitted to android using USB serial communication. However in scope of this block only a function call is done for USB serial communication. Finally, this whole process will loop back with a frequency of 10Hz by producing a delay of 100ms after every iteration. So, either the sound localization would be done on data from microphones or recorded file, in both of cases same set of instructions will be executed.   Download
Enclosure The enclosure was developed specifically for this project, taking all measurements from hardware used to design a handheld enclosure for the device. It has two pieces, a lower part and an upper part. This is the lower part.   Download
Enclosure The enclosure was developed specifically for this project, taking all measurements from hardware used to design a handheld enclosure for the device. It has two pieces, a lower part and an upper part. This is the upper part   Download
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