In this project we created a baby cry detection (recogniton) device. The device can recognize baby-cry while ignoring other sounds like human speech, music, and so on. The project consists of several phases, among them are research, a development of a unique digital signal processing algorithm, software development, physical creation of the circuits, physical creation of the device, and quality assurance tests. The device was built for a customer, as a part of a patent appeal that involves the detection of baby-cry.
Research In this phase the algorithm for the baby-cry recognition was created. How do we recognize voice? Voice recognition divides into two main areas: one is recognition by training a model, and the other is recognition without training a model. In the former method a "learning algorithm" is given several samples of the voice needed to be recognized, and the algorithm calibrates different parameters so it will recognize the studied voice. In the later method, the recognition should be immediate and there's no prior preparation and training of a model. In our case the customers' request was to recognize the cry of any baby, and not training the device to detect the cry of a certain baby. So how was the cry-detection algorithm created? In the first stage, we analyzed tenses of baby-cry samples using Matlab. Them, we did a process called "Feature Extraction", process in which the parameters that are unique to baby cry are found and calibrated. Then, we implemented the algorithm in Matlab, and tested it over baby cry and other sound samples. After successfully finishing with the tests, the algorithm was transfered to it's hardware implementation using a Micro-Processor. The development of the Electrical Circuit The customers' requirement was to create a prototype that it's goal is to prove the ability of cry detection. Since it's a prototype, we were told that the main issues are the quality and the prototyping time of the device, and not it's size or it's interface. So we decided to indeed focus on quality, and used analog buttons and led indicators for the interface.The algorithm was implemented in hardware using two micro-processors, on which a C software was burnt.
The PrototypeAbout the prototype: - On the right:
- 12v transformer connector
- On\Off Switch
- Power On led indicator
- On the front:
- Microphone sensitivity button (so that the device can be put anywhere in the room, not necessarily near the baby)
- Desired cry detection time button
- On the upper side:
- A dark-yellow led which indicates the detection of a sound.
- A light-yellow led which indicated the detection of a baby cry
- A green led which indicates the detection of a baby cry for the desired amount of time set by the white button.
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Baby Cry Detector
