CN105302088A - Smart home system and control method based on brain-computer interface and Zigbee - Google Patents

Abstract

The present invention is based on the brain-computer interface and Zigbee smart home system and control method. The system has an EEG acquisition module, an EEG signal processing module, a display module, a smart home controller, and home equipment connected in series in sequence, and through visual stimulation. The visual stimulator module enables the brain to generate EEG signals, and the display module also visually feeds back the collected signals to the subjects, and at the same time displays the triggered household appliance instructions. The methods include: setting the frequency of the visual stimulator so that the 12 LED light-emitting blocks flicker steadily at different frequencies; the human eye fixation flicker module collects the steady-state visual evoked potential signal of the human brain by the EEG acquisition module. The collected EEG signal enters the EEG signal processing module after analog-to-digital conversion. After the signal is processed by band-pass filtering and power spectrum estimation algorithm, the command is sent to the smart home controller by the serial port. The controller sends instructions wirelessly to designated home devices. The invention does not need language and body movements as information transmission media, and provides a method for controlling the external home environment and equipment by using brain electricity.

Description

Smart home system and control method based on brain-computer interface and Zigbee

technical field

The invention relates to a smart home system and a control method based on a brain-computer interface and Zigbee. In particular, it involves a method of controlling a smart home only through EEG signals, providing a way for disabled people with physical disabilities to communicate with the outside world.

Background technique

In recent years, the brain-computer interface has been gradually applied from the laboratory stage, especially in the field of control as a new technology is being widely developed, such as the use of EEG signals to control space robots, intelligent wheelchairs, etc. Because it does not require body movements and only relies on bioelectrical signals to achieve control of designated equipment, it has been widely introduced into the fields of many special environmental operations, bringing huge portability, and also proposed new solutions to problems in many application fields. Program.

The smart home system and control method based on the brain-computer interface and Zigbee is a method of using a visual stimulator to induce the human brain to generate specific EEG signals to realize the control and communication of people with the external home environment. It only relies on human vision and EEG signals as the transmission medium to realize the control and communication of the human brain with external devices. This method has greatly helped the rehabilitation life of the disabled, reduced the nursing workload of medical staff and family members, helped the physically disabled to live independently, improved their quality of life and gave them the right to enjoy life.

Steady-state visual evoked potentials, as a common input signal for human-computer interaction systems, have the advantages of high information transmission rate, short training time and easy feature extraction, and only need the signals of a few electrodes located in the occipital cortex to extract. The smart home technology based on the brain-computer interface is based on the traditional smart home, and the brain-computer interface technology is introduced into it, and a brand-new solution is proposed for the convenience of life for the disabled and entertainment.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for controlling a smart home system by brain electricity, so as to achieve a system that only uses steady-state visual evoked potentials to control a smart home system without physical movements.

The technical scheme adopted in the present invention is, based on the brain-computer interface and Zigbee smart home system and control method, including a smart home control system consisting of a signal acquisition module, an EEG processing module, a display module, and a wireless sensor network connected in series. Devices and household equipment, and a visual stimulator module that causes the brain to generate EEG signals through visual stimulation, and the display module also visually feeds back the collected EEG signals to the subject.

The signal acquisition module includes a scalp electrode connected to the human brain, two ear electrodes, a preamplifier, a power frequency notch circuit, a filter circuit, a postamplifier and an A\D conversion module. The output end of the signal acquisition module is connected to the input end of the EEG processing module.

Described EEG processing module is set up on LabVIEW software, comprises the steps:

i) collect data from the signal acquisition module and store it;

ii) Judging whether the sampling time is greater than the set time, if not, continue to store data;

iii) Judging that the sampling time is greater than the set time, and reading the data;

iv) Process the stored data, use a bandpass filter with a passband range of 10-20Hz, a stopband attenuation of 60dB, and a passband ripple of 1dB for filtering and denoising;

v) Perform feature extraction on the filtered data using power spectrum estimation. Calculate the power spectrum of the collected EEG signal, extract the frequency value corresponding to the maximum power as the feature value, and use the method of template matching to convert it into a control signal;

vi) Find out the instructions issued by the human brain according to the processing results, and display them on the display module;

Vii) send the control signal after the template matching to the smart home controller by serial port communication;

The template matching method is to output the light-on instruction after the 13Hz EEG signal is processed, and output the light-off instruction after the 13.5Hz EEG signal is processed, and so on, every 0.5Hz is a unit interval, from 13Hz-18.5Hz respectively represent commands: lamp on, lamp off, fan on, fan off, radio on, radio FM, TV on, TV off, TV volume up, TV volume down, TV channel up, TV channel down.

The visual stimulator includes 12 groups of frequency display modules displaying 12 different frequencies, and each display module is realized by driving an LED light emitting module (D1-D12) through a triode (Q1-Q12). The frequencies displayed by the 12 different LED lights respectively represent: desk lamp on, desk lamp off, electric fan on, electric fan off, radio on, radio tuning (addition and subtraction), TV on, TV off, TV channel plus, TV channel minus , TV volume up, TV volume down.

The smart home system and control method based on the brain-computer interface and Zigbee are characterized in that, including the following stages:

1) Set the frequency of the visual stimulator so that 12 different LED light-emitting blocks flash steadily at their respective frequencies;

2) Place a scalp electrode on the occipital region of the back of the human brain, place two ear electrodes on the left and right ears, and make people's vision parallel to 12 LEDs with different frequencies that emit light quickly, and the EEG collected by the scalp electrodes The collected EEG signal is amplified and A\D converted and then sent to the EEG processing module for processing;

3) displaying the instructions of the smart home system triggered by the human brain through the display module;

The smart home controller is responsible for communicating with the EEG processing module, and sending the processed EEG instructions to the household equipment.

The household equipment is composed of Zigbee wireless network, including a desk lamp module, an electric fan module, a radio module, and a TV module.

The present invention is based on a brain-computer interface and a Zigbee smart home system and control method, which brings a new method for smart home control and has wide practicability and applicability. The invention can help disabled people with movement disorders and people with special needs, especially disabled people who need monitoring to realize their daily independent life. For ordinary people with normal vision who have limited mobility, the present invention can also provide an effective way to communicate with the outside world.

Description of drawings

Fig. 1 is an overall block diagram of the present invention

Fig. 2 is a functional block diagram of the signal acquisition module of the present invention

Fig. 3 is the instruction button diagram of the display module of the present invention

Fig. 4 is a functional block diagram of household equipment of the present invention

Fig. 5 is the overall control flowchart of the present invention

in:

1: Signal acquisition module 2: EEG processing device

3: Display Module 4: Visual Stimulator

5: Smart Home Controller 6: Home Appliances

11: Preamplifier 12: Power frequency notch circuit

13: filter circuit 14: post amplifier

61: desk lamp 62: electric fan

63: Radio 64: Television

detailed description

The smart home system and control method based on the brain-computer interface and Zigbee of the present invention will be described in detail below in conjunction with the drawings and experiments.

The smart home system and control method based on the brain-computer interface and Zigbee in the present invention use the steady-state visual evoked potential phenomenon generated by the flash visual stimulation of the human eye and combine the Zigbee Internet of Things smart home technology to design a set of brain-electricity-controlled household appliances. system. The present invention uses the silver chloride electrode to only collect the signal at the O1 position of the occipital area of the subject's brain, and combines two ear reference electrodes to realize the extraction of the human brain signal.

As shown in Figure 1, the smart home system and control method based on the brain-computer interface and Zigbee of the present invention include a signal acquisition module (1), an EEG processing module (2), a display module (3), Visual stimulator module (4), smart home controller (5) and home equipment (6). The signal acquisition module (1) is mainly responsible for collecting the bioelectrical signals of the human brain from the silver chloride electrode, and performing analog-to-digital conversion to complete the conversion from the bioelectrical electroencephalogram signals to digital signals. The EEG signal processing module (2) mainly processes the digital EEG signals received from the signal acquisition module (1), recognizes characteristic values after processing, and converts them into control commands to control the lower computer household equipment (6). The display module (3) visually feeds back the collected signals and triggered home appliance instructions to the subject.

As shown in Figure 2, described signal acquisition module (1) comprises preamplifier (11), industrial frequency notch circuit (12), filter circuit (13), postamplifier (14) and A\D conversion module (15). After the EEG signal enters the signal acquisition module, it passes through each module in turn. The output end is connected to the signal input end of the EEG signal processing module (2) by a USB data cable.

The visual stimulator (4) includes 12 groups of LED light-emitting modules displaying 12 different frequencies. According to the generation mechanism of steady-state visual evoked potentials, the frequencies are respectively distributed between 13Hz-18.5Hz at intervals of 0.5Hz. Represent commands respectively: desk lamp on, desk lamp off, electric fan on, electric fan off, radio on, radio FM, TV on, TV off, TV volume up, TV volume down, TV channel plus, TV channel minus. Wherein, the light-emitting module adopts white LED lights. The triode adopts S8050 chip. In order to avoid interference between adjacent LEDs, the light-emitting blocks are packaged into a square with a side length of 2 cm, and the distance between adjacent light-emitting blocks is 2 cm. The subjects selected the corresponding control command by looking at one of the 12 LED lights with different frequencies.

The present invention is based on brain-machine interface and Zigbee smart home system and control method, including the following stages:

1) Design the frequency of the stimulator so that the 12 white LED light-emitting modules flash steadily at different frequencies from 13Hz to 18.5Hz at intervals of 0.5Hz.

2) Make people's vision look at 12 different luminescent stimulation modules in parallel. Collecting EEG signals through scalp electrodes, amplifying and A/D converting the collected EEG signals, and sending them to the EEG processing module (2) for EEG processing;

3) As shown in Figure 3, the instructions of the smart home system triggered by the human brain are displayed through the display module (3);

As shown in Figure 5, the processing (2) of described EEG signal comprises the following stages:

i) collect data from the signal acquisition module and store it;

ii) Judging whether the sampling time is greater than the set time, if not, continue to store data;

iii) Judging that the sampling time is greater than the set time, and reading the data;

iv) Process the stored data, use a bandpass filter with a passband range of 10-20Hz, a stopband attenuation of 60dB, and a passband ripple of 1dB for filtering and denoising;

v) Perform feature extraction on the filtered data using power spectrum estimation. Calculate the power spectrum of the collected EEG signal, extract the frequency value corresponding to the maximum power as the feature value, and replace it with the control signal by using the method of template matching. The power spectrum estimation algorithm of the described calculation feature extraction is calculated by the following formula:

$\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; N</span>}}{<span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; FFT</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span><span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$

Treat the N observation data of the signal x(n) as a sequence with limited energy, directly calculate the discrete Fourier transform x(k) of x(n), then take the square of its amplitude, and divide it by N, as the sequence x (n) Estimation of the true power spectrum. In the template matching method, if the EEG signal of 13 Hz is processed, the light-on command is output, and if the EEG signal of 13.5 Hz is processed, the light-off command is output, and so on, and every 0.5 Hz is a unit interval;

vi) Find out the instructions issued by the human brain according to the processing results, and display them on the display module (3);

Vii) Utilize serial port communication to send the control signal after template matching to the smart home controller (5);

The EEG processing modules described in the present invention are all built on the upper computer LabVIEW software. The program of steady-state visual evoked potential acquisition and processing, real-time processing of EEG signals and feedback of experimental results are integrated. When the EEG acquisition is completed, the EEG acquisition channel, sampling frequency and time settings can be completed. In this system, the standard setting is to conduct real-time processing of EEG signals every 2S. The EEG display area can simultaneously display EEG commands in real time. As shown in Figure 4, after template matching, the EEG signal extracted by the feature is transmitted to the smart home controller (5) by serial port communication, and then transmitted to each home device (6) by using the Zigbee wireless network. Desk lamp (61), electric fan (62) are realized by Zigbee module control relay, radio (63) is realized by Zigbee module control, TV (64) is realized by Zigbee module control infrared module.

Through experimental verification, the correct rate of the smart home system and control method based on the brain-computer interface and Zigbee of the present invention is as high as 100% after the test and training. The average time for the subjects to send a single command is within 5 seconds, and the farthest transmission control distance can reach 50 After training, all the subjects were able to complete the trigger switch action of the complete set of equipment within the specified time, realizing the purpose of real-time control of household appliances by using only EEG signals without physical movements. The invention shows the feasibility and practicability of the intelligent home system control method based on the brain-computer interface, has good real-time performance and recognition rate, can accurately judge people's intentions, and has good use value.

Claims (8)

1. A smart home system and control method based on brain-computer interface and Zigbee, characterized in that it includes a signal acquisition module (1), an EEG processing module (2), a display module (3), and a smart home A controller (5), household equipment (6), and a visual stimulator module (4) that causes the brain to generate EEG signals through visual stimulation, and the display module (3) provides visual feedback to the subjects collected signals and instructions. 2. The smart home system and control method based on brain-computer interface and Zigbee according to claim 1, characterized in that, the signal acquisition module (1) includes a preamplifier (11), a power frequency notch circuit (12), filter circuit (13), post amplifier (14) and A\D conversion module (15). The processed EEG signal enters the EEG processing module (2) through a USB data cable. 3. smart home system and control method based on brain-computer interface and Zigbee according to claim 1, it is characterized in that, described EEG processing module (2) is built on LabVIEW software, comprises the steps: i) collect data from the signal acquisition module and store it; ii) Judging whether the sampling time is greater than the set time, if not, continue to store data; iii) Judging that the sampling time is greater than the set time, and reading the data; iv) Process the stored data, use a bandpass filter with a passband range of 10-20Hz, a stopband attenuation of 60dB, and a passband ripple of 1dB for filtering and denoising; v) Perform feature extraction on the filtered data using power spectrum estimation. Calculate the power spectrum of the collected EEG signal, extract the frequency value corresponding to the maximum power as the feature value, and use the method of template matching to convert it into a control signal; vi) Find out the instructions issued by the human brain according to the processing results, and display them on the display module (3); Vii) Send the control signal after the template matching to the smart home controller (5) by serial port communication. 4. The smart home system and control method based on the brain-computer interface and Zigbee according to claim 3, wherein the template matching method is to output the light-on instruction after the 13Hz EEG signal is processed, If the 13.5Hz EEG signal is processed, the light-off command is output, and so on, every 0.5Hz is a unit interval, and the commands from 13Hz-18.5Hz are: desk lamp on, desk lamp off, electric fan on, electric fan off, radio on , Radio FM, TV on, TV off, TV volume up, TV volume down, TV channel plus, TV channel minus. 5. The smart home system and control method based on brain-computer interface and Zigbee according to claim 1, wherein said visual stimulator (4) includes 12 groups of frequency display modules showing 12 different frequencies, Each display module is realized by driving an LED light emitting module (D1-D12) through a triode (Q1-Q12). The frequencies displayed by the 12 different LED light-emitting blocks respectively represent: desk lamp on, desk lamp off, electric fan on, electric fan off, radio on, radio FM, TV on, TV off, TV volume up, TV volume down, TV Channel change plus, TV channel minus. 6. A smart home system and control method based on brain-computer interface and Zigbee for claim 1, characterized in that, comprising the following stages: 1) Set the frequency of the visual stimulator so that 12 different LED light-emitting blocks flash steadily at their respective frequencies; 2) Place a scalp electrode on the occipital region of the back of the human brain, place two ear electrodes on the left and right ears, and make people's vision parallel to 12 LEDs with different frequencies that emit light quickly, and the EEG collected by the scalp electrodes The signal is sent to the EEG processing module (2) for EEG processing after amplifying and A/D converting the collected EEG signals; 3) The display module (3) displays the instructions of the smart home system triggered by the human brain, and the smart home controller (5) sends the instructions to the home equipment (4). 7. the smart home system and control method based on brain-computer interface and Zigbee according to claim 1, is characterized in that, described smart home controller (5) is in charge of communicating with EEG processing module (2), will The processed EEG instructions are sent to the household equipment (6) by the Zigbee wireless module. 8. The smart home system and control method based on the brain-computer interface and Zigbee according to claim 1, wherein the home equipment (6) is composed of a Zigbee wireless network, including a desk lamp module (61), an electric fan module (62), radio module (63), television module (64).