Design of indoor walking service system for elderly and disabled people based on AVR voice recognition

1.1 Introduction

At present, the number of people over 60 years old in the world has reached about 600 million, and population aging has become a major social problem worldwide. In my country, the number of people over 60 years old has reached 132 million, accounting for 10% of the total population, and continues to grow at an average annual rate of 3.32%. It is estimated that by 2015, the population over 60 years old will exceed 200 million, accounting for about 14% of the total population, of which about 50% of patients with geriatric diseases need nursing services. In addition, there are about 60 million disabled people of various types in my country, accounting for about 5% of the total population. Therefore, the total number of people in my country who need nursing care is about 100 million. The accelerated aging of the population has put unprecedented pressure on the medical and social insurance systems. Among the 1.3 billion people in my country, there are about 300 million to 400 million families, and families with functional disabilities or caregivers account for 1/10 of the total number of households in the country, about 35.77 million. The large number of disabled people and long-term bedridden elderly people has made the issue of helping the elderly and the disabled increasingly a major social issue. Improving the quality of life and self-care ability of the elderly and disabled, developing service products to assist the elderly and disabled, and providing them with services such as walking and indoor living have become issues of common concern to the whole society.

1.2 Project Background/Motivation for Topic Selection

At present, there are more than 30 million elderly and disabled people with physical disabilities in my country. When walking, they need to rely on manpower or equipment, such as wheelchairs. Most of the current household appliances do not support voice recognition. The switch of electrical appliances is usually realized by buttons or remote controls. Before achieving control, the precise position or direction of the controlled device (such as buttons, remote control objects, etc.) must be found, which is very troublesome for users with limited mobility.

Therefore, the development of systems to assist the elderly and the disabled has important practical significance, and plays an important role in improving the quality of life of the elderly and the disabled and ensuring the harmony, stability and development of our society.

In order to actively carry out scientific and technological innovation practice activities among college students, and to cultivate the learning ability of AVR microcontrollers among students in school, this topic was selected for the study of AVR microcontrollers.

2. Demand Analysis

2.1 Functional requirements

1. The wheelchair can be effectively controlled to move freely through voice control;

2. Realize automatic control of household appliances in the home;

3. Realize the control of access control system;

4. Real-time monitoring and release of home security information can be selectively achieved based on the level of knowledge mastered.

2.2 Performance requirements

1. This system uses voice to issue relevant control commands and alarm commands;

2. Household appliances and their peripherals are implemented using simulation functions;

3. Use a four-wheeled vehicle model instead of a wheelchair to achieve free movement forward, backward, left and right;

4. The electric light replaces the switch quantity of household appliances to realize the switch control of household appliances;

5. Use DC motor to simulate the automatic opening and closing function of access control;

6. Use the timer software of the AVR microcontroller to simulate the remote control to realize the remote control function of household appliances;

7. Realize mobile phone dialing and SMS alarm functions through GPRS (depending on the capability).

3. Solution Design

3.1 System Function Implementation Principle

The overall design scheme of the indoor walking service system for the elderly and disabled based on AVR voice recognition is shown in Figure 1. The voice signal is collected by the voice processing module through the microphone on the development board, and then sent to the AVR processor for recognition. The AVR microprocessor analyzes and determines the command type of the voice based on the recognition result, and completes the corresponding operation according to the command requirements. The AVR microprocessor sends the relevant operations to the corresponding execution devices such as access control devices, wheelchair drive devices, etc. through the wireless module, receives the command and completes the corresponding action; the system can monitor the outdoor situation through the camera, and transmit the video information to the LCD display for real-time display. The user decides whether to open the access control system based on the identity of the visitor; the automatic dialing of the mobile phone is realized through voice, and the mobile phone is used to make calls and seek help.

Figure 1 Overall block diagram of the system

3.2 Hardware platform selection and resource allocation

1. The hardware platform uses an EVK1100 development system based on the AVR32 AT32UC3A microcontroller controller. The specific resource configuration is as follows:

2. The basic input and output ports of the AT32UC3A microcontroller are used to control the switch quantity;

3. The serial communication interface of the single-chip microcomputer is used for communication with the voice module and the wireless control module;

4. The PWM of the microcontroller is used to control the steering and speed of the wheelchair;

5. Ethernet port for video input from monitors;

6. Develop system sensors (light, temperature) for humanized prompts and control of household appliances, weather forecasts, and other functions;

7. 4x20 blue LCD (PWM variable frequency backlight) is used to display control information and its related status.

3.3 System Software Architecture

The system software environment uses AVR Studio 5, the official development tool provided by ATMEL, and the program is mainly programmed in C language.

3.4 System Software Process

1. Main program design

Figure 2 Main program flow chart

In the main program, a modular design is adopted to complete the training and storage of a specific person's voice. After the training is successful, voice recognition is performed and related operations are executed according to the recognized commands, as shown in Figure 2.

1. Speech recognition software design

The speech recognition method is to establish a template library after preprocessing and feature extraction of speech signals, match the speech signal to be recognized with the template library according to the speech features, and perform speech recognition based on the matching distance. The basic process of speech recognition is shown in Figure 3.

Figure 3 Basic flow chart of speech recognition

1. Serial communication software design

When voice controls a wheelchair or home appliance, the system sends different instructions to the main control board through the serial port according to the type of control statement recognized to achieve various control functions. The flowchart of the system serial port communication program is shown in Figure 4.

Figure 4 Serial communication flow chart

1. Infrared remote control programming

The infrared remote control signal is a series of binary pulse codes. In order to prevent it from being interfered by other infrared signals during wireless transmission, it is usually modulated on a specific carrier frequency and then transmitted through an infrared light-emitting diode. The infrared receiving device will filter out other clutter and only receive the signal of the specific frequency and restore it to a binary pulse code, which is demodulation. The infrared program design process is shown in Figure 5.

Figure 5 Infrared programming flow chart

3.5 Expected Results of the System

Through hard work, we sincerely hope to achieve the expected functions. All specific functions can be realized and there is time for optimization. We hope that the real product will be a prototype with great simulation significance, and it would be best if a company could invest in making the product.