CN104955092A - WIFI prompt sticker based on WIFI signal detection and intensity display purpose - Google Patents

Abstract

The invention discloses a WIFI prompt sticker based on the purpose of WIFI signal detection and intensity display, belonging to the technical field of WIFI signal detection. In this reminder, the number of luminous signal lights is posted to represent the strength of the WIFI signal. The more luminous signal lights, the stronger the signal strength, and vice versa. There are three main functions, namely signal detection function, signal processing function, signal comparison and display function. The signal detection function is mainly completed by the LC frequency selection circuit. The signal processing function converts the AC voltage into the required DC voltage. The signal comparison and display function displays the strength of the signal through voltage comparison. The invention enables people to know at a glance the WIFI signal situation at the current location without opening the peripheral device.

Description

A WIFI reminder sticker based on WIFI signal detection and strength display purpose

technical field

The invention relates to a reminder sticker device which can be used to detect whether there is a WIFI signal and can prompt the strength of the WIFI signal in the current area through the number of luminous signal lamps, and belongs to the technical field of WIFI signal detection.

Background technique

With the rapid development of today's information age, people's demand for information is increasing day by day, and the Internet is the most convenient and quick way for people to obtain information in today's society. Therefore, being able to obtain information anytime and anywhere, and how to obtain information quickly and accurately has become the main requirement of modern people for the network. With the popularity of wireless mobile terminals such as smartphones and tablet computers today, people have become a very mainstream way of surfing the Internet to obtain information through WIFI outdoors. WIFI is a technology that can connect personal computers or mobile terminals to each other wirelessly. WIFI is a brand of wireless network communication technology, held by the WIFI Alliance (WiFi Alliance), the purpose is to improve the interoperability between wireless network products based on the IEEE802.11 standard.

The use of WIFI to connect to the network can be simply understood as wireless Internet access. Almost all smart mobile terminal phones, computers, etc. support WIFI Internet access, which is a widely used wireless network transmission technology. In fact, the wired network signal is converted into a wireless signal, and the wireless router is used as the transmitter of the radio frequency signal for the receiving terminal computer, mobile phone, tablet, etc. that support its technology to receive it. Through the smart phone that supports WIFI function, in the area with WIFI wireless signal, we can not use the network package provided by our operator, thus saving a certain amount of traffic and costs. However, WIFI signals are also provided by wired networks, such as household broadband ADSL and community optical cables, and only need to connect to a wireless router to convert wired signals into WIFI signals. Many cities in developed countries abroad are covered with WIFI signals provided by the government or large companies for residents to use. We can also see WIFI signs in our country. For example, there will be WIFI coverage in most coffee shops or some buses. In the pilot cities where 4G licenses have not been issued, many places use 4G to WIFI for citizens to use. Due to technical limitations, the quality of wireless communication transmitted by WIFI technology is not very good, and the data security performance is slightly worse than that of Bluetooth, but the transmission speed is very fast, which can reach 54Mbps, which meets the needs of individuals and social informatization at a faster pace. The main advantage of WIFI is that no wiring is required, so it is very suitable for the needs of mobile office users, and because the transmission signal power is lower than 100mw, which is lower than the transmission power of mobile phones, it is relatively safe to use WIFI to connect to the network. The general WIFI signal receiving radius About 95 meters, but it will be affected by walls, etc., the actual distance will be smaller. The frequency bands are divided according to different regions around the world. IEEE802.11b/g works in the 2.4-2.4835GHz frequency band, and the FCC standard adopts 2.412-2.462 GHz has a total of 11 channels, the ETSI standard uses a total of 13 channels from 2.412 to 2.472 GHz, and Japan uses a total of 14 channels from 2.412 to 2.484 GHz, and the domestic wireless routers include the above.

In order to facilitate users to clearly understand which places have WIFI signals, and can clearly display the strength of WIFI signals, it is convenient for people to choose places with high signal strength to use WIFI to connect to the network through mobile terminals, thus proposing a method that can detect WIFI signals And the electronic reminder label showing its strength allows users to directly see the WIFI signal situation, whether there is a signal and the strength of the signal at a glance without taking out the mobile phone or tablet computer to search for the WIFI signal.

Contents of the invention

The purpose of the present invention is to provide a reminder sticker based on WIFI signal detection and intensity display, which is similar to an electronic label. Some prominent positions in public places are convenient for pedestrians to understand the situation of WIFI signals in the area, and they can also carry the reminder stickers with them. Users no longer need to take out their mobile phones to detect the strength of WIFI signals, and can directly see the strength of the signal. Compared with It is more convenient to take out the mobile phone to check the WIFI signal, and it has the characteristics of being easy to know and display. This reminder sticker can represent the strength of the WIFI signal through the number of luminous indicator lights. The more luminous signal lights, the stronger the signal strength, and vice versa. The present invention mainly has three main functions, namely signal detection function, signal processing function, and final signal display function. The signal detection function is mainly completed by the LC frequency selection circuit. Its main function is to detect and receive the IEEE802.11b/g standard 2.4G high-frequency WIFI signal, and convert the high-frequency signal into an AC that changes with the high-frequency signal. The voltage signal is the part received by the previous section number before the signal prompts to be posted. The signal processing function is mainly to complete the voltage signal conversion and provide power for the subsequent circuit. Its main function is to convert the AC voltage signal output by the LC frequency selection circuit that changes with the strength of the high-frequency WIFI signal into a signal that changes with the strength of the high-frequency WIFI signal. The variable DC voltage, and then the stable DC voltage obtained after the limiting circuit and the LDO voltage stabilization process is used to provide power for the internal circuit structure of this reminder, and the variable DC voltage signal obtained by the rectifier circuit can represent high Frequency WIFI signal strength. Finally, the previously processed signals are compared and displayed. This part of the function is completed by the multi-channel comparison unit and the display unit. The DC voltage signal output by the previous rectifier circuit that changes with the high-frequency signal is used as the voltage to be compared. The circuit is compared with the threshold, and the final comparison result can be displayed on the display unit. During the entire display process, the stronger the WIFI signal, the more signal lights will be illuminated, otherwise, the fewer signal lights will be illuminated. Different numbers of signal lights of the same color are used to distinguish Different WIFI signal strengths are convenient for people to understand the situation of WIFI signals.

The present invention is a WIFI reminder sticker based on the purpose of WIFI signal detection and intensity display, which is characterized in that it includes a signal receiving unit, a signal processing unit (or a power supply unit) and a signal comparison and display unit, and the function of the signal receiving unit is mainly a signal The detection function is mainly completed by the LC frequency selection circuit. Its main function is to detect and receive the 2.4G high-frequency WIFI signal of the IEEE802.11b/g standard, and the selected L and C can meet the resonance requirements; the signal processing unit (or power supply Unit) includes three parts: rectification circuit, limiter circuit, LDO circuit, the rectification circuit rectifies the AC voltage signal output by the LC frequency selection circuit of the signal receiving unit, and then obtains the DC voltage signal that changes with the change of the high frequency signal intensity, which is about to The AC voltage signal is converted into a DC voltage signal. This DC voltage signal is used as the voltage to be compared. The stronger the high-frequency signal, the greater the voltage to be compared. The minimum value of the voltage to be compared is recorded as V _min , and the maximum value is recorded as V _max , the voltage to be compared is connected to the signal comparison and display unit, and at the same time, the DC voltage output by the rectifier circuit that changes with the change of the high-frequency signal strength is limited to the maximum voltage amplitude of the DC voltage by the limiter circuit to V ₁ , V ₁ is less _than V _min ; the output voltage _of the limiting circuit is passed through the LDO circuit to make the output voltage have better DC characteristics. As the total threshold, where V ₃ =V _max , and at the same time the output voltage V ₃ of the amplifying circuit is connected to the signal display unit as the total threshold.

The signal comparison and display unit includes four resistance rheostats, four voltage comparators, four resistors, and four display units. The output of the LDO circuit is respectively connected to the four voltage comparators to provide them with operating voltage. The four resistance rheostats connected in series, and then each resistance rheostat is connected in parallel with a voltage comparator, a resistor and a display unit to form a circuit loop, in which four series resistance rheostats are connected in series with the output voltage V _of the amplifying circuit, which is the total threshold value, to form a loop, and each voltage The inverting input terminal of the comparator is connected to the resistor rheostat connected in parallel with it, and the non-inverting input terminal is connected to the output of the rectifier circuit, so that the voltage to be compared output by the rectifier circuit is compared with the divided voltage threshold value of each resistor rheostat, if If the voltage to be compared is greater than the sub-voltage threshold, the signal light of the display unit connected to it is on, otherwise it is not on. By adjusting the resistance rheostat to make each sub-voltage threshold different, the more the signal lights of the display unit are lit, it indicates the voltage to be compared. The larger the value, the stronger the corresponding WIFI signal.

The display post of the present invention can divide the area with strong WIFI signal and prompt the user, which is convenient for people to use mobile phones, computers (tablets) and other peripheral terminals to access the network through WIFI. It is suitable for various public places and can also be loaded in In the car, people can know the WIFI signal situation of the current location at a glance without opening the peripheral device.

Description of drawings

Fig. 1 is a block diagram of the signal receiving unit and the signal processing unit of the WIFI signal strength prompt sticker;

Fig. 2 is a block diagram of the overall module of the WIFI signal strength prompt sticker;

FIG. 3 is a circuit diagram of the multiple comparison unit and the display unit in FIG. 2 , that is, a circuit structure diagram of the signal display unit.

Detailed ways

The following sub-modules illustrate the specific module design of the present invention. First, the signal processing part: this module mainly includes a signal receiving unit and a signal processing unit (or a power supply unit), wherein the signal processing unit is composed of a rectifier circuit, a limiter circuit and an LDO. , this unit provides power for subsequent modules.

Signal receiving unit: The signal receiving unit relies on the electromagnetic coupling of the external inductance coil to perceive and obtain energy. This part is composed of an LC resonant frequency selection circuit, which uses the amplitude-frequency characteristics and phase-frequency characteristics of the LC circuit to select useful signals from the input signal. Frequency components, while suppressing noise and invalid frequency components. Here, the values of L and C need to be calculated. If L is too large, the resistance of the corresponding parasitic resistance will also be large, so that part of the energy is consumed on the internal resistance of the inductor, which makes the energy obtained by the load not optimal; at the same time , L can not be too small. If L is too small, although the energy consumed by the internal resistance of the inductor is reduced, a very large quality factor Q will be obtained. A high quality factor Q will make the frequency slightly deviate from the resonance frequency, resulting in a sharp drop in the output AC voltage amplitude. Therefore, When designing the frequency selection circuit, it is necessary to choose the appropriate L and C to meet the resonance requirements. The main function of this unit is to convert the high-frequency WIFI signal into an AC voltage signal that changes with it.

The signal processing unit (or power supply unit) processes the received signal and provides power to the circuit modules of the subsequent signal comparison part. The function of the rectifier circuit in this unit is that the LC frequency selection circuit in the signal receiving unit converts the external high-frequency WIFI signal into an AC voltage signal through LC resonance. The AC voltage signal output by the frequency loop is rectified to obtain a DC voltage signal as the voltage to be compared, that is, to convert the sensed high-frequency WIFI signal into a DC voltage signal that changes with the intensity of the high-frequency signal (here set the voltage to be compared The minimum value of the voltage is V _min and the maximum value is V _max , which depends on the actual external environment) and the stronger the high-frequency signal, the greater the voltage to be compared, and the comparison of different WIFI signal strengths is converted into a comparison of different voltage amplitude. In this way, the high-frequency WIFI signal can be converted into a measurable DC voltage signal. At the same time, when the WIFI signal is too weak or the prompt sticker is too far away from the WIFI signal transmitter (or router, etc.), the voltage value generated at both ends of the coupling inductor is too small, and the turn-on voltage of the rectifier circuit cannot be reached, resulting in failure to provide stable voltage. The power supply, the subsequent part of the module unit circuit cannot work normally, and the display unit cannot display the result, indicating that the WIFI signal cannot be detected at the location of the prompt or the signal strength is weak. The final power supply is generated by adding a limiter circuit and LDO on the basis of the rectifier circuit, and the DC voltage value output by the rectifier circuit that changes with the high-frequency signal strength is limited to the maximum amplitude by the limiter circuit. Set here V ₁ , due to the limitations of the limiting circuit itself, V ₁ has a certain ripple, and the ripple size is determined by the time parameter obtained by the product of the load resistance and the load capacitance at the output end, so an LDO is added after the limiting circuit To make the output voltage have better DC characteristics, set this voltage output as V ₂ , and this voltage output provides power for the subsequent signal comparison part.

The second module design to realize the present invention is the signal comparison and display part: this module mainly includes a multi-channel comparison unit and a display unit.

Multi-way comparison unit and display unit: The multi-way comparison unit is mainly composed of four voltage comparators, where the non-inverting input of the comparator is the voltage to be compared, that is, the voltage obtained through the rectification circuit changes with the change of the high-frequency WIFI signal strength. The amplitude of the voltage to be compared, by comparing different voltages to be compared to indicate the strength of the high-frequency signal, the inverting input of the comparator has four different voltage thresholds that can be adjusted for the random input with the non-inverting input The WIFI high-frequency intensity changes and the voltage to be compared is compared. The thresholds of the four comparators in the multi _- way comparison unit are the voltage values obtained by the stable voltage V2 output by the previous power supply unit through the voltage amplification circuit (here set as V ₃ ) That is, the total threshold, which is obtained by dividing the voltage of the resistor. If the voltage value of the non-inverting input terminal of the voltage comparator is greater than the threshold voltage of the inverting input terminal, the comparator outputs a high level, so that the corresponding signal lamp in the display unit is lit, and the signal lamp controlled by the comparator with a higher threshold voltage is placed in a relatively In the upper position, the signal lights controlled by the comparator with a lower threshold voltage are placed in the lower position, so that when the high-frequency WIFI signal strength is high, a row of signal lights are all lit from bottom to top, when the high-frequency WIFI signal When the intensity is low, only the signal lights on the lower floor are lit, so the strength of the high-frequency WIFI signal is judged by the number of signal lights that glow from bottom to top. In the present invention, when the rectifier circuit outputs the maximum voltage to be compared, that is, when the high-frequency WIFI signal is the strongest, the signal light corresponding to the comparator with the maximum threshold value can be lit, so here through the design of the parameters of the amplifying circuit The obtained total threshold value V ₃ is the same as the maximum voltage value V _max output by the rectification circuit, that is, V _max =V ₃ . By adjusting the size of the voltage dividing resistor, the minimum threshold of the comparison circuit is the same as the minimum voltage V _min output by the rectification circuit, so that the total threshold can be prevented from being too small, and when the comparison voltage is large, the display unit is always at four signal lights The state of being lit at the same time; or the total threshold value is too large, and the voltage to be compared is small, and the voltage to be compared cannot make the signal light on the comparator with a larger threshold light up, so that the output result of the display unit is inaccurate. An innovation of the present invention is that the four voltage dividing resistors in the multi-way comparison unit are set as four variable resistors that can adjust the resistance value of the resistors. The use of variable resistors for voltage division here is mainly to obtain The operator independently adjusts the threshold according to the surrounding environment. This is done to deal with the small impact that the surrounding environment of different areas may have on the high-frequency WIFI signal. The voltage value range output by the rectifier circuit has a certain deviation, so here through The adjustment of the resistance value of the voltage dividing resistor is used to change the threshold value so as to correct this small deviation and prevent the results displayed by the display unit from being inaccurate.

The present invention will be further described below in conjunction with the accompanying drawings.

As shown in Figure 1, the overall design block diagram of the signal receiving and signal processing circuit part of the present invention, this part includes a signal receiving unit, and a signal processing unit (or power supply unit), wherein the signal processing unit is mainly composed of a rectifier circuit and a limiter circuit and LDO composition. The signal receiving unit is composed of LC frequency selection circuit, which is mainly used to receive the 2.4G high-frequency WIFI signal emitted from the WIFI signal transmitter in the surrounding electromagnetic field, and select it through the LC frequency selection circuit that has calculated the resonant frequency. The frequency signal is selected and converted into an AC voltage that changes with the signal strength. The AC voltage is used as the input of the rectifier circuit. If the input amplitude of the AC voltage is too small, it cannot meet the working voltage of the transistor in the rectifier circuit, and cannot provide power, resulting in subsequent If the circuit module cannot work, it is considered that the high-frequency WIFI signal is too small. When the rectifier circuit works normally, the output voltage value is as mentioned above. The maximum value is V _max and the minimum value is V _min . The maximum output voltage V _max corresponds to the WIFI The high-frequency signal is the strongest, on the contrary, the high-frequency signal corresponding to the minimum voltage V _min is the minimum. The voltage to be compared outputted by the rectification circuit is compared by the comparison unit. The LDO output provides a stable power supply with small ripples for subsequent circuit modules.

The design block diagram of the signal comparison and display part is shown in Figure 3. This part is mainly composed of multiple comparison circuits and a display unit. The main input of this module is the voltage to be compared output by the rectifier circuit. The range is as mentioned above (V _min , V _max ), the total threshold input for comparison is V ₃ obtained after the LDO output voltage V ₂ is amplified (V ₃ should be the same as V _max ), the power supply of this module is the LDO output voltage V ₂ , the input of this module is mainly composed of the above It consists of three parts. The display unit is a group of four signal lamps arranged in a row. When the high-frequency signal is strong, the number of the signal lamps is more, and vice versa.

As shown in Figure 3, the circuit structure of the signal comparison and display part, the non-inverting input terminals of the four comparators in the middle are the voltages to be compared output by the rectifier circuit, and the inverting input terminals are different voltages obtained by dividing the total threshold value through the variable resistors. Compared with the threshold, the total threshold in the figure is replaced by a constant voltage source, whose amplitude should be the same as the maximum value V _max output by the rectifier circuit.

As shown in Figure 2, it is the overall structural block diagram of the present invention, wherein the amplifying circuit is in order to obtain the total threshold value V ₃ equal to the output maximum value V _max of the rectifying circuit, and the three inputs of the multi-way comparison unit are respectively power supply, voltage to be compared and total threshold. The total threshold is divided by four variable resistors in the multi-way comparison unit to obtain different thresholds. Here, the voltage divider is set as a variable resistor, the purpose of which is to facilitate the use of different thresholds for different external environments. , so that the comparison result obtained by the present invention is more accurate.

Claims (8)

1. A WIFI reminder sticker based on WIFI signal detection and strength display. 2. The WIFI reminder sticker according to claim 1, characterized in that the reminder sticker includes a signal receiving unit, a signal processing unit, a signal comparison and display unit inside. 3. The WIFI reminder sticker according to claim 2, characterized in that, the function of the signal receiving unit is mainly a signal detection function, which is mainly completed by an LC frequency selection circuit, and its main function is to detect and receive the IEEE802.11b/g standard 2.4G high-frequency WIFI signal, the selected L and C must meet the resonance requirements. 4. according to the WIFI reminder sticker of claim 2, it is characterized in that, described signal comparison and display unit comprise four resistance rheostats, four voltage comparators, four resistors, four display units, and the output of LDO circuit is connected with four respectively. A voltage comparator is connected to provide working voltage for it. Four resistance rheostats are connected in series, and then each resistance rheostat is connected in parallel with a voltage comparator, a resistor and a display unit to form a circuit loop, in which four series resistance rheostats are connected with a display unit. The output voltage V _of the amplifying circuit is connected in series to form a loop, the inverting input terminal of each voltage comparator is connected with the resistance rheostat connected in parallel, and the non-inverting input terminal is connected with the output of the rectifier circuit, that is, the voltage to be compared, so that the output of the rectifier circuit is to be compared The voltage is compared with the sub-voltage threshold of each resistance rheostat. If the voltage to be compared is greater than the sub-voltage threshold, the signal light of the display unit connected to it will be on, otherwise it will not be on. By adjusting the resistance rheostat to make each sub-voltage The thresholds are different, the more the signal lights of the display unit are lit, the larger the voltage to be compared is, and the stronger the corresponding WIFI signal is. 5. according to the WIFI reminder post of claim 2, it is characterized in that, described signal processing unit comprises three parts: rectification circuit, limiter circuit, LDO circuit. 6. The WIFI reminder sticker according to claim 5, wherein the rectification circuit rectifies the output AC voltage signal of the LC frequency selection circuit of the signal receiving unit to obtain a DC voltage signal that varies with the high-frequency signal strength, This DC voltage signal is used as the voltage to be compared. The stronger the high-frequency signal, the greater the voltage to be compared. The minimum value of the voltage to be compared is recorded as V _min , and the maximum value is V _max . connected to the display unit. 7. The WIFI reminder sticker according to claim 6, characterized in that, the limiter circuit is mainly used to limit the DC voltage output by the rectifier circuit that changes with the high-frequency signal strength after limit the maximum voltage of the changed voltage The amplitude is limited to V ₁ , which is smaller _than V _min . 8. The WIFI reminder sticker according to claim 6, characterized in that, the LDO circuit makes the output voltage have better DC characteristics and less ripple after the voltage output by the limiter circuit is passed through the LDO circuit, and the output voltage of the LDO circuit is The voltage is recorded as V ₂ , and the voltage output by the LDO circuit is adjusted by the amplifier circuit so that the output voltage V ₃ is used as the total threshold, where V ₃ =V _max , and the output voltage V ₃ of the amplifier circuit is connected to the signal display unit as the total threshold.