Smart toilet design and development

At this stage, with the continuous advancement of technology, smart toilets have gradually entered thousands of households, and people's performance requirements for smart toilets are also further improving. The human body motion detection method using PSD can no longer meet people's needs. Applying microwave sensing technology to smart toilets can design a more concise and fashionable bathroom style, improve the functions of smart toilets, and meet human needs. It can better promote Related industries continue to develop and contribute to the country's economic development.

1. The principle of microwave sensing technology used in smart toilets

1.1 Detection principle of traditional smart toilet applications

Traditional smart toilets detect human movement by installing position sensors and infrared monitors in the toilet. Although they can accurately judge human movements, they are easily affected by the surrounding environment and cause detection errors. As a passive motion sensor, the infrared detector is easily affected by the environment such as temperature. Moreover, these two human detection tools cannot be applied to non-transparent materials, and it is often necessary to set additional windows on the toilet to achieve the purpose of detection, which seriously affects the overall design effect of the toilet. Using microwave sensing technology and Kepler principle to realize the function of human motion detection, while ensuring the overall design effect of the toilet, it can also detect human motion more accurately.

1.2 Microwave sensing technology human motion detection principle

Microwave sensing technology emits high-frequency electromagnetic waves into the air to cover the toilet. When the human body approaches the toilet, it will naturally enter the coverage of the microwave sensor. The electromagnetic wave emitted by the microwave sensor will automatically reflect back after touching the human body. The incoming electromagnetic wave outputs an intermediate frequency signal, which is the Doppler signal. The Doppler signal removes the noise in the signal through the notch filter, amplifies the signal, transmits it to the single-chip microcomputer for identification, and finally measures the signal frequency to make corresponding response actions. After the Doppler signal enters the single-chip microcomputer, different signal processing is carried out through the acquisition and processing modules, and the frequency of the incoming and outgoing signals of the frequency module is detected. The amplitude detection module detects the amplitude of the signal, and finally reaches the signal processing module. Use the obtained information and the probability information of the machine's initial set value to process the signal, and send it back to the single-chip microcomputer to give feedback on the action task performed this time. When no one is using it, the amplitude and frequency of the Doppler signal sent by the microwave sensing technology remain relatively unchanged; when someone approaches, the microwave sensor automatically senses the distance and movement speed, and the amplitude of the signal will also increase relatively ; When the person leaves, the signal amplitude decreases relatively. The amplitude and frequency of the Doppler signal are respectively determined by the position between the human and the smart toilet and the relative speed of the two.

1.3 Human body detection movement process of microwave sensing technology

Take an intelligent bathroom system design company as an example. The core of the smart toilet designed by the company is a single-chip microcomputer to detect the approach of the human body. After assuming the amplitude frequency of the preset value and the corresponding judgment conditions, the function data change detection of the intelligent toilet designed by the enterprise is carried out. When the experimenter moves towards the direction of the microwave sensor, the Doppler signal will continue to increase, but because there is still a certain distance between the experimenter and the sensor, there are still a lot of noise and noise in the signal, after being processed by the signal filter , the signal is continuously amplified by the low-frequency amplifier. The method of AC coupling in the amplification process can not only effectively remove the DC component in the signal, but also keep the signal clear during the amplification process. The signal processed by the low-frequency amplifier alone cannot be recognized by the microcontroller. In order to solve this problem, the technicians of the company further amplify the amplified signal through an adjustable amplifier, and then use numerical control technology to control the degree of signal amplification until the Doppler signal can be identified.

The magnification of the adjustable amplifier is determined according to the function of the single-chip microcomputer used by the enterprise. At the same time, the recorder records the amplitude and frequency at this time, and directly inputs the amplified Doppler signal into the single-chip microcomputer for further processing. Because the experimenter is constantly approaching, the amplitude and frequency are also constantly changing. In addition to recording the signal, the recorder also needs to record and store the amplitude and frequency through computer technology, and summarize the rules through algorithms. Compared with the initial preset conditions, it is found that when the amplitude and frequency are gradually increasing and the amplitude is a rising curve, the microwave sensor controller will automatically judge that the tester is effectively approaching, and then execute the corresponding action signal output; on the contrary, if the conditions are not met, the microwave sensor controller will not have any signal output response. Through the waveform diagram output by the company's technicians after the event, it was found that when the tester moved from a distance to the front of the smart toilet, the entire curve of the signal was in an upward trend after being detected by relevant software; while in the tail waveform The curve has a certain downward trend. At this time, the tester just walked to the position of the smart toilet and stopped moving. Although the waveform dropped at this time, the toilet received the corresponding command from the microwave smart sensor and had already made action tasks such as flipping the lid. While the experimenter is moving far away from the Doppler sensor, the waveform detected by the microwave detection device shows a downward trend as a whole; when the waveform drops to the longest distance from the effective position, the smart toilet flushes and flushes according to the response command. The task of closing the cover.

At the same time, let the experimenter approach the microwave sensor from the side, and the waveform diagram formed in the later stage shows that the overall trend is upward. The single-chip microcomputer collects the corresponding Doppler signal, and detects the corresponding amplitude and frequency, and extracts the corresponding change trend after processing the signal. Make a prediction based on the trend information, and finally execute the corresponding command signal output. The single-chip microcomputer mainly relies on the amplitude and frequency and the overall change trend in the process of judging the action. These three aspects must be preset in advance, and the collected and analyzed information is compared with the preset information through the computer system of the controller. If all the conditions are met, it will be judged as valid, and the corresponding action will be executed. If any of the conditions are not met, it will be regarded as an invalid judgment. Through such a judgment process and specific judgment conditions, the application of microwave sensing technology in smart toilets is realized.

2. Smart toilet sensor hardware design

2.1 MCU design of intelligent toilet system

The single-chip microcomputer is the core existence in the microwave sensing system. The Doppler signal released by the microwave sensing is judged by the single-chip microcomputer, and the corresponding signal action is output. The single-chip microcomputer used in a smart toilet is an 8-bit single-chip microcomputer produced in the United States. This single-chip microcomputer has good performance and a large amount of storage function. It can store the parameter settings of the system and use it in the later software initialization. In addition, the single-chip microcomputer also has a wealth of peripheral functions without additional settings, which strengthens the integration of functions, simplifies the design steps, and reduces the design cost to the greatest extent. At present, most of the single-chip microcomputers used in China use A/D converters to collect and process Doppler signals, and transmit the signals to the processing module for analysis through a 10-bit converter. At the same time, a serial port module for enhanced communication is used in the system , Strengthen the communication between the main control system of the intelligent toilet and the single-chip microcomputer, ensure that the information can be transmitted to the main control system of the intelligent toilet in time, and make corresponding responses according to human body movements.

2.2 Application advantages of microwave sensors

Microwave sensor is the main hardware embodying microwave sensing technology. It is small in size, low in power consumption and high in sensitivity. It is an ideal device that can be widely used for human detection in smart toilets. The high-frequency electromagnetic waves are sent out through the micro-antenna that comes with the device, and it is judged according to the reflected waves reflected by the electromagnetic waves, and finally forms a Doppler signal. Microwave sensing technology is meaningless without microwave sensors.

Take the smart toilet developed by a company as an example. The microwave mobile sensor used by the company can form X-band mobile sensing Doppler signals. Through the formation principle of Doppler signals, the Doppler signals with the characteristics of intermediate frequency signals are processed and transmitted to the microcontroller. As the basic equipment for realizing the smart toilet, the microwave sensor must not only have a good signal transmission function, but also ensure a relatively unified sense of equipment with the smart toilet.

2.3 Notch filter and circuit of microwave sensing technology

From the operating principle of microwave sensing technology, it can be known that the Doppler signal released by the microwave sensor is used for judgment, but there are many noises and noises in the signal during the movement process, and the overall signal changes slowly, so it is necessary to set the corresponding The advanced notch filter and shaping circuit process the signal. After the signal is processed, the signal is clear and clear, and then the next step is expanded to ensure the accuracy of the signal fundamentally, and will not cause misjudgment by the single-chip microcomputer. In the process of using the smart toilet, the microwave sensing technology mainly detects the movement of the human body. The movement of the first detection target is approaching and leaving. The designer of a smart toilet found in the continuous analysis process that the signal in the microwave sensing technology The frequency fluctuates between 30 and 80 Hz. Once it is disturbed by the environment and the radiation in the power grid, the frequency will easily increase to 100 Hz or even 120 Hz, resulting in a wrong judgment of the overall signal and erroneous actions.

In the overall design, a notch filter and a shaping circuit are added to process the signal: first, through the notch filter, deal with the interference of the external environment, and keep the signal at a normal frequency; second, use the shaping circuit to shape the signal to eliminate The interference signal among them ensures that the single-chip microcomputer can judge the frequency of the Doppler signal more accurately. After the experimenter installed the notch filter and shaping circuit, the hertz of the external environment was weakened by the notch filter, and the clutter frequency was effectively filtered out by the filter. Only on the basis of a certain frequency of the signal, can the relevant equipment in the later stage be more accurate in determining the signal.

2.4 Microwave Sensing Technology Adjustable Gain Amplifier

The electromagnetic waves released by microwave sensing technology are relatively weak and cannot be effectively sensed by the single-chip microcomputer. The signal can only be amplified relatively to a certain extent through a numerically adjustable gain amplifier to ensure that the single-chip microcomputer can effectively receive the corresponding signal for judgment. The Doppler signal will gradually weaken during the transmission process, but the microwave sensors used in different smart toilets are different, and the models of single-chip microcomputers are also different. The Doppler signal after passing through the low-frequency amplifier is still relatively weak. The adjusted gain amplifier can realize the function of the single chip microcomputer to receive the signal. According to the functions of different single-chip microcomputers, the multiples of the amplified signal are adjusted and controlled to ensure that the signals can be effectively received by the single-chip microcomputer. Take the numerical control adjustable gain amplifier used in the intelligent toilet developed and designed by a bathroom enterprise as an example. The amplifier includes two types: fixed amplifier and adjustable amplifier. The amplifier achieves gain adjustment by adjusting the resistance value of the potentiometer. The potentiometer is a digital potentiometer produced in the United States, which is a low-cost 50kΩ. The potentiometer also has the control of the sliding end of the interface, which can achieve the purpose of controlling the sliding end according to the different serial degrees of signal increment and decrement, but because of its own volatility, the current control value for the sliding end cannot be saved after power off. Therefore, the company saves the value of the sliding end in the system software, and restores the value of the sliding end through system initialization at the beginning of the system. Using this method, the gain adjustment is more perfect, and the adjusted signal is perfectly received by the single-chip microcomputer. The numerical control adjustable gain amplifier is the most critical part in microwave sensing technology, only through the amplifier can the operation of subsequent judgment actions be guaranteed.

3. Software Design of Microwave Sensing Technology for Intelligent Toilet

After designing the hardware technology of the microwave sensing technology, it is necessary to design the corresponding software technology for the microwave sensing technology. The software system mainly includes initialization system, waveform acquisition system, amplitude and frequency monitoring system, communication and signal sensitivity system for detection. After the software starts, first of all, it needs to initialize the device, including the initialization of the system itself and internal and external functions, and then set the sensitivity and judgment parameters. This step is the most critical step in the software operation process. Only by improving the sensitivity and decision parameters of the system can the normal and accurate operation of the system be guaranteed. Secondly, use the communication module to execute corresponding instructions on the toilet. At this time, the software itself detects and processes the amplitude and frequency of the signal according to the signal response of the waveform acquisition module fed back. After analysis, it judges that the control instruction is established and outputs the corresponding instruction. signal, the toilet completes the command; if the command is judged to be invalid, an invalid signal will be output accordingly.

Summarize

This paper discusses in detail the application principle of microwave sensing technology in intelligent toilet, and designs the functions of various hardware and software of intelligent toilet according to the relevant principles, mainly reflecting the detection of human body movement through microwave sensing system, and according to the human body The movement responds accordingly, such as controlling the toilet flip, flushing, etc., thereby improving the related functions of the smart toilet, and further promoting the application of the smart toilet in life.

The above are the details of the smart toilet solution introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. for you. If you have the design and development needs of smart toilets, you can trust us. We have rich experience in customizing and developing electronic products. We can evaluate the development cycle and IC price as soon as possible, and can also calculate PCBA quotations. We are a number of chip agents at home and abroad: Songhan, Yingguang, Jieli, Ankai, Quanzhi, realtek, with MCU, voice IC, Bluetooth IC and module, wifi module. Our development capabilities cover PCB design, single-chip microcomputer development, Bluetooth technology development, software customization development, APP customization development, WeChat official account development and other hardware and software design. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the development of electronic education products.