CN102592403A - Microcomputer eyesight protecting voice prompter - Google Patents

Abstract

The invention relates to a voice prompter for microcomputer vision protection. It adopts the single-chip microcomputer 3 as the core, including the ultrasonic transmitting circuit 4, the ultrasonic reflection receiving circuit 5 and the illuminance detection circuit 6, and is characterized in that: the single-chip microcomputer 3 is controlled by the first I/O port P1.2 with A/D acquisition function and The illuminance detection circuit 6 is connected, the illuminance detection circuit 6 comprises a photosensitive sensor 16 and a sampling circuit 17, the photosensitive sensor 16 and the sampling circuit 17 form a series circuit, and the connection point between the photosensitive sensor 16 and the sampling circuit 17 is connected to the first part of the single chip microcomputer 3 An I/O port control pin P1.2 is used as the signal input end of the A/D converter in the single chip microcomputer 3 . The present invention also includes a key input circuit 7 , a voice output control circuit 8 , a battery voltage sampling circuit 9 and a power supply and battery charge and discharge management circuit 11 . The invention can remind the readers of the sight distance and light in time during the reading process.

Description

Microcomputer vision protection voice prompter

technical field

The invention belongs to the field of electronic technology, and relates to a voice prompter for microcomputer vision protection. It mainly reminds people that when reading books and newspapers, the human eyes should keep an appropriate distance from the book, and the light should be adjusted to an appropriate brightness, so as to avoid eyesight loss and myopia caused by eye fatigue caused by careless reading.

Background technique

At present, there is a phenomenon of younger age myopia, and many teenagers wear glasses at a young age. The main reasons are (1) Many teenagers read books in the wrong posture, often lying on the table when reading, so that the eyes are too far away from the book. (2) Improper light illumination when reading books makes the eyes prone to fatigue, which will lead to vision loss for a long time; (3) Reading for too long, excessive use of eyes, etc.

The existing technology mainly prompts for sitting posture and reading and writing distance, so as to play a certain role in vision protection. Multifunctional electronic vision protection device for vision protection; another example is CN200520051053.2, the invention name is "Microcomputer Multifunctional Student Eyesight Protection Pencil Box", when the student's reading and writing posture is incorrect or the straight line distance between the eyes and the pencil box is less than too close, the alarm will be triggered The device is automatically switched on, and reminds students to make corrections through light or sound to avoid eye fatigue of students and prevent myopia.

However, if the light is too strong, strong light will be reflected into the eyes when the light hits the white book, causing eye fatigue. This is often referred to as "light pollution"; Big eyes can also cause visual fatigue over time. These are due to poor illumination, which causes visual fatigue, which is also one of the main reasons for vision loss and myopia. Therefore, in order to protect the eyesight of teenagers and make them grow up healthily, an intelligent vision protection voice prompter can detect and prompt the light intensity of the reading environment in real time and remind them to keep a suitable reading distance, which will be more conducive to protecting the eyesight of teenagers.

Contents of the invention

The object of the present invention is to provide a microcomputer eyesight protection voice prompter which adopts computer technology and electronic information processing technology to design and has ultrasonic distance measurement, lighting detection, time timing, voice alarm control and battery charge and discharge protection device.

Technical scheme of the present invention:

It uses a single-chip microcomputer 3 as the core, including an ultrasonic transmitting circuit 4, an ultrasonic reflection receiving circuit 5, and an illumination detection circuit 6. The single-chip microcomputer 3 is controlled by the first I/O port with A/D acquisition function P1. Connect, light intensity detection circuit 6 comprises photosensitive sensor 16 and sampling circuit 17, photosensitive sensor 16 and sampling circuit 17 constitute series circuit, connect the first I/O of single-chip microcomputer 3 from the connection point between photosensitive sensor 16 and sampling circuit 17 The port control pin P1.2, the first I/O port control pin P1.2 is used as the signal input end of the A/D converter in the single-chip microcomputer 3 .

The microcomputer eyesight protection voice prompter also includes a key input circuit 7 , a voice output control circuit 8 and a battery voltage sampling circuit 9 .

The inside of the chip of the single-chip microcomputer 3 is equipped with an A/D converter, and the chip contains program memory, data memory and at least 11 I/O port control pins, wherein at least 2 I/O port control pins have A/D Acquisition function, the chip of the single-chip microcomputer 3 has a built-in crystal oscillator. The on-chip crystal oscillator is used as the system clock.

The photosensitive sensor 16 is an LXD/GB5-A1DPH photosensitive sensor, and the sampling resistor in the sampling circuit 17 is 2KΩ.

The illuminance detection method is: after the photosensitive sensor 16 is connected in series with the sampling circuit 17, the photosensitive sensor 16 feels the intensity of the light, so that the voltage signal on the sampling resistor changes; The O port control pin P1.2 performs A/D conversion into digital quantities, and the software scale conversion algorithm is designed to calculate the current illuminance value through the single-chip microcomputer 3 program design, and finally compared with the standard value to control the voice alarm prompt; through the single-chip microcomputer 3 The first I/O port control pin P1.2 continuously detects the light illumination in real time, and realizes real-time alarm prompts when the illumination is insufficient.

Described single-chip microcomputer 3 outputs ultrasonic signal wave through the second I/O port control pin P1.0, and is connected with the input terminal of ultrasonic transmitting circuit 4, and ultrasonic transmitting circuit 4 comprises driving circuit 12 and ultrasonic transmitting sensor 13, and ultrasonic signal passes through The drive circuit 12 sends the discharge to the ultrasonic transmitting sensor 13, and the ultrasonic transmitting sensor 13 transmits an ultrasonic signal.

The third I/O port control pin P3.3 of the single-chip microcomputer 3 is connected with the output end of the ultrasonic reflection receiving circuit 5 as an external interrupt signal input end; the ultrasonic reflection receiving circuit 5 includes an ultrasonic receiving sensor 14 and an ultrasonic reflection demodulation circuit 15. The ultrasonic reflection demodulation circuit 15 performs signal discharge, amplitude limiting, band-pass filtering, wave detection, integration, and shaping to make an external interrupt signal, which is sent to the third I/O port control pin P3.3 of the single-chip microcomputer 3 .

The fourth I/O port control pin P1.1 with A/D acquisition function of the single-chip microcomputer 3 is connected to the battery voltage sampling circuit 9 as the A/D sampling signal input terminal, and the battery voltage sampling circuit 9 is connected to the lithium battery 22 ; After lithium battery 22 work discharges to certain voltage value, battery voltage sampling circuit 9 gathers the battery voltage value of this moment and sends into single-chip microcomputer 3 to carry out calculation comparison processing, when the voltage value gathered is less than the built-in battery discharge valve of single-chip microcomputer 3 When the value is V _t , the single chip microcomputer 3 is connected to the undervoltage indicator light 10 through the fifth I/O port control pin P3.

The sixth, seventh and eighth I/O port control pins P3.0, P3.1, P3.4 of the single-chip microcomputer 3 are respectively connected with 3 buttons K1, K2, K3, and 3 buttons K1, K2, K3 is connected with key input circuit 7, wherein:

The first button K1 is the reset alarm button, that is, after pressing the K1 button, the timing alarm starts counting from zero, and when the count is equal to the preset time value, an alarm prompt "take a rest"; Press the K1 key, and the timer will alarm once every 5 minutes to prompt "Pay attention to rest";

The second button K2 is the timing time setting button. There are 5 options for the timing time. The preset is 45 minutes, press the K2 key for the third time, the timing time is preset to 60 minutes, press the K2 key for the fourth time, the timing time is preset to 90 minutes, press the K2 key for the fifth time, the timing time is preset 120 minutes, press the K2 key for the 6th time, the timing time returns to the preset value of 30 minutes; and so on, the key functions are processed in a loop;

The third button K3 is the ultrasonic distance measurement setting key, which has 5 kinds of ultrasonic distance measurement setting options, and is a circular processing button: press K3 for the first time, and the ultrasonic distance measurement preset is 20cm, and press K3 for the second time key, the ultrasonic ranging preset is 25cm, press the K3 key for the third time, the ultrasonic ranging preset is 30cm, press the K3 key for the fourth time, the ultrasonic ranging preset is 35cm, press the K3 key for the fifth time, The ultrasonic distance measurement is preset to 40cm, press the K3 key for the 6th time, and the ultrasonic distance measurement returns to the preset value of 20cm. By analogy, the button functions are processed in a ring.

The ninth, tenth and eleventh I/O port control pins P1.5, P1.6, P1.7 of the described single-chip microcomputer 3 are used as voice output control signal ends, and three input ports of the voice output control circuit 8 A0, A1, and A2 are connected, and the voice output control circuit 8 includes a voice storage circuit, a control circuit 18 and a loudspeaker 19.

The microcomputer vision protection voice prompter also includes a power supply and battery charge and discharge management circuit 11; the power supply and battery charge and discharge management circuit 11 includes a resistance-capacitance step-down rectifier circuit 20, a charging indicator light 28, a battery charge management chip 21, a lithium battery Battery 22, sampling circuit 23, working switch 24, electronic switch 25, voltage stabilizing block 26, and ripple processing circuit 27;

When the system works normally to supply power, the lithium battery 22 supplies power; the positive pole of the lithium battery 22 is connected to the working switch 24, and the inside of the working switch 24 is a mechanical contact. Turn on the power and start working; the drain of the electronic switch 25 is connected to the A terminal of the working switch 24, the source of the electronic switch 25 is connected to the input terminal Vi of the voltage stabilizing block 26, and the tube grid of the electronic switch 25 is connected to the sampling circuit 23 connection; the voltage stabilizing block 26 steps down the input voltage and then outputs +5V from the Vo end to provide an operating voltage for the vision protection prompter 1; a capacitor is used for ripple processing through the ripple processing circuit 27, and is connected in parallel to Vo output;

The charging of the lithium battery 22 is realized by a 220V AC resistance-capacity step-down rectifier circuit 20; the resistance-capacity step-down rectifier circuit 20 first uses a resistor and a capacitor in parallel, and then connects a resistor in series, the other end of the series resistor is connected to the eyesight protection prompter The power line of 1 is connected to plug 2, and plug 2 is connected to 220V AC voltage; after the RC step-down, it is connected to a rectifier bridge composed of 4 diodes; the output end of the rectifier bridge is connected in parallel to a capacitor composed of 1000uF and The filter and voltage regulator circuit composed of 12V voltage regulator tube reduces the input 220V AC voltage to 12V voltage regulator output;

The output terminal of the resistance-capacitance step-down rectifier circuit 20 is connected to the charging indicator light 28 and the input terminal of the sampling circuit 23; the sampling circuit 23 is connected to the electronic switch 25 after being divided by two resistors; the output terminal of the charging indicator light 28 is connected to the The working switch 24 and the input terminal of the lithium battery 22 are respectively connected to the VDD and VSS terminals of the battery charging management chip 21 through the resistors R1 and C1, the Cout terminal of the battery charging management chip 21 is connected to the grid of Q1, and the Dout terminal is connected to the grid of Q2. pole, the drains of Q1 and Q2 are connected together, and the sources of Q1 and Q2 are respectively connected to the negative pole of the filtered and stabilized voltage output and the negative pole of the lithium battery 22;

When the power cord and plug 2 of the eyesight protection prompter 1 were inserted into the AC 220V power outlet, the electronic switch 25 was controlled by the sampling circuit 23 to disconnect instantly, so that the lithium battery 22 stopped discharging and outputting, at this moment, the lithium battery 22 was charged; the lithium battery 22 Charging management is in charge of by the battery charging management chip 21, and when charging normally, the charging indicator light 28 is on; If after the battery is fully charged, the charging indicator light 28 is off.

The invention is simple in operation and strong in applicability, realizes modular design in circuit design and programming technology, and "dumb" operation, so that the system can remind readers in time during the reading process, bringing a lot of convenience to readers.

The present invention has realized following function:

1. Ultrasonic accurate distance measurement, the distance measurement accuracy reaches ±1cm.

2. Critical lighting illumination detection, the critical illumination is 400lx.

3. "Keep distance" alarm prompt: When it is detected that the reading distance is less than a certain set distance (default is 30cm), it indicates that the human eye is too close to the book, and the control output voice alarm prompts "Keep distance".

4. "Light is too dark" alarm prompt: According to the national standard for lighting and lighting hygiene in classrooms (GB7793-87), the average illuminance on the classroom desktop is not less than 400lx (lux). Therefore, when the illuminance of the detected light is less than 400lx, it indicates that the illuminance is too small, and then the control outputs a voice alarm prompting "the light is too dark".

5. "Pay attention to rest" alarm prompt: the internal design has a clock counter, which starts time counting from reading. If the reading time exceeds a certain set time (default is 45 minutes), it will control the output voice prompt "pay attention to rest" for reminder Readers take a break to relax their minds and improve their learning efficiency. After that, the voice prompts "take a break" every 5 minutes, and the timing alarm will not start again according to the preset timing time until the K1 key is pressed.

6. Timing time can be set: 5 levels of timing and alarm can be set through the K2 key. There are 5 options for the timing time. Press the K2 key for the first time and the timing time is preset to 30 minutes. Press the K2 key for the second time. The timing time is preset to 45 minutes, press the K2 key for the third time, the timing time is preset to 60 minutes, press the K2 key for the fourth time, the timing time is preset to 90 minutes, press the K2 key for the fifth time, the timing time The preset time is 120 minutes, press the K2 key for the 6th time, and the timing time is preset to 30 minutes.

7. Ultrasonic ranging alarm can be set: 5 levels of ultrasonic ranging and alarm can be set through the K3 key. Press the K3 key for the first time, and the ultrasonic ranging preset is 20cm. Press the K3 key for the second time, and the ultrasonic ranging The preset is 25cm, press the K3 key for the third time, the ultrasonic ranging preset is 30cm, press the K3 key for the fourth time, the ultrasonic ranging preset is 35cm, press the K3 key for the fifth time, the ultrasonic ranging preset is 40cm, press the K3 key for the 6th time, the ultrasonic distance measurement preset is 20cm.

8. Power supply and battery charge and discharge management circuit: 220V AC step-down to charge the battery, powered by the battery, with battery power detection and protection functions to prolong the service life of the battery.

The present invention is especially suitable for juveniles and children to promptly remind them that their reading posture is wrong, prompting whether the light is insufficient or the eyes are too close to the desk and books in class, and it can also detect and remind in real time whether the light brightness of the reading environment such as classrooms is appropriate, which can be effective. Protect the eyesight of young children.

1. The present invention can well realize the alarm reminder of the reading time, can give an alarm to the reading environment light is too weak, can timely warn the reading distance is too close, can prevent the fatigue caused by excessive use of the eyes for a long time, and protect the eyesight It has good applicability and brings good news to readers, especially children readers.

2. Electronic technology, control technology and computer technology are used in the realization method, and the orderly work of the whole system is controlled by the single-chip microcomputer, and the ultrasonic distance measurement, light brightness detection, voice storage output and battery charge and discharge protection are controlled to make the system stable and reliable. work.

3. Modular design is carried out in circuit design and programming technology, "fool-like" operation, simple and convenient operation, easy to learn and easy to use, ensuring the safety and reliability of the system.

Description of drawings

Fig. 1 is a schematic diagram of the overall structure of Embodiment 1 of the present invention.

Fig. 2 is a schematic diagram of the circuit connection of the automatic detection and control part of the single-chip microcomputer in Embodiment 1 of the present invention.

Fig. 3 is a schematic structural diagram of an ultrasonic transmitting circuit according to Embodiment 1 of the present invention.

FIG. 4 is a schematic structural diagram of an ultrasonic reflection receiving circuit according to Embodiment 1 of the present invention.

FIG. 5 is a schematic structural diagram of an illumination detection circuit according to Embodiment 1 of the present invention.

FIG. 6 is a schematic structural diagram of a voice output control circuit according to Embodiment 1 of the present invention.

Fig. 7 is a schematic structural diagram of the power supply and battery power supply circuit in Embodiment 1 of the present invention.

Detailed ways

Embodiment 1: it includes the automatic detection and control circuit of the vision protection microcomputer voice prompter, which is realized by the single-chip microcomputer 3 (U1), as shown in Figure 2: the single-chip microcomputer 3 is the core of the whole control system as a microcontroller, and the whole control system The interior includes single-chip microcomputer 3, ultrasonic transmitting circuit 4, ultrasonic reflection receiving circuit 5, illuminance detection circuit 6, key input circuit 7, voice output control circuit 8, battery voltage sampling circuit 9, undervoltage indicator 10, and power supply and battery charge and discharge management The circuit part such as circuit 11 is constituted.

In this embodiment, the single-chip microcomputer (U1) adopts STC12C5402AD chip produced by STC Hongjing Company and packaged in SOP16. 11 I/O port control pins (6 of which have A/D acquisition function), using on-chip 12MHz crystal oscillator. The single-chip microcomputer manages and controls all surrounding chips and circuits through 9 I/O ports. Among them, P1.0 of the single-chip microcomputer (U1) is used as an output port, connected with the ultrasonic transmitting circuit 4, and used as an output to transmit ultrasonic signals. The ultrasonic transmitting circuit 4 is composed of a driving circuit 12 and an ultrasonic transmitting sensor 13 . The drive circuit 12 uses a medium-power Darlington tube or two composite triodes to amplify and drive the 40KHz ultrasonic signal, and drives the ultrasonic transmitting sensor 13 to emit ultrasonic signals. The ultrasonic transmitting sensor 13 uses a T40-16 sensor element, which can receive an AC signal with a working frequency of 40KHz, generate resonant ultrasonic waves and transmit them into space to realize long-distance transmission. Ultrasound has the characteristics of good directionality, can become ray and directional propagation and so on.

P3.3 of the single-chip microcomputer 3 is used as an external interrupt input port, and is connected with the ultrasonic reflection receiving circuit 5 as an external interrupt trigger signal. The ultrasonic reflection receiving circuit 5 uses an ultrasonic receiving sensor 14 and an ultrasonic reflection demodulation circuit 15 . The ultrasonic receiving sensor 14 adopts R40-16 sensor element, and the ceramic vibrator transducer inside it can generate a mechanical vibration signal after receiving the ultrasonic wave, and amplify it and transform it into electrical energy output, so as to realize the detection of the sent ultrasonic wave. The signal output by the R40-16 sensor is directly sent to the ultrasonic reflection demodulation circuit 15 . The ultrasonic reflection demodulation circuit 15 uses a CX20106A ASIC, which can receive waveforms in the frequency range of 30-60KHz, and the center frequency of reception can be set by adjusting the resistance of the fifth pin. When using a 200k resistor, the center frequency of the receiver is 40KHz. Then the signal transmitted by the R40-16 sensor is amplified (the total amplification gain is 80db), filtered, and finally sent to the P3.3 pin of the microcontroller as an external interrupt signal.

P1.2 of the single-chip microcomputer 3 is used as the signal input terminal of the on-chip A/D converter, and is connected with the series circuit formed by the photosensitive sensor 16 and the sampling circuit 17 . For the photosensitive sensor LXD/GB5-A1DPH, the sampling circuit is a 2KΩ resistor. After the photosensitive sensor 16 is connected in series with the sampling circuit 17, the photosensitive sensor 16 senses the intensity of light, and the voltage signal on the sampling resistor changes. The voltage changed by the light is sent to P1.2 for A/D conversion into digital quantities, and the current illuminance value is calculated through the software scale conversion algorithm, and finally compared with the standard value to control the voice alarm prompt. Continuous real-time detection of light illumination through P1.2, to realize real-time alarm prompt when the illumination is insufficient.

P1.1 of the single-chip microcomputer 3 is used as the signal input terminal of the on-chip A/D converter, and detects whether the battery voltage is undervoltage in real time. P1.1 is directly connected with the battery voltage sampling circuit 9 . The battery voltage sampling circuit is composed of two resistors connected in series, and then connected in parallel with the lithium battery 22, and P1.1 is directly connected to the middle of the two resistors. When the battery supplies power normally, the battery voltage value will gradually decrease, so that the voltage drop across the two resistors will also change. The changed voltage drop is sent to P1.1 for A/D conversion into digital quantity, and the current lithium battery voltage value is calculated through the software transformation algorithm, and finally compared with the limit value to control whether to alarm and stop working. When the voltage value of the lithium battery collected by the A/D is less than its discharge threshold V _t , the single-chip microcomputer 3 controls the undervoltage indicator 10 to flash for warning, and the undervoltage indicator 10 will flash for warning after 1 minute and then automatically enter the power-down protection state . P3.7 in the single-chip microcomputer 3 is connected with the undervoltage indicator light 10, and the undervoltage indicator light 10 uses a light emitting diode.

The single-chip microcomputer 3 uses three I/O ports of P3.0, P3.1, and P3.4 as K1, K2, and K3 buttons respectively to form a button input 7, which is used as a button input switch signal. Key input 7 uses a mechanical contact key component. When the K1 key is pressed, it inputs a low level (effective key) to P3.0; when it is not pressed, P3.0 is high level; when the K2 key is pressed When pressed, input low level to P3.1 (effective key); if not pressed, P3.1 is high level; when K3 key is pressed, input low level to P3.4 (effective key); If it is not pressed, P3.4 is high level (invalid key). The K1 key is used to reset the alarm, the K2 key is used to set the timing time, and the K3 key is used to set the ultrasonic distance measurement alarm.

The single-chip microcomputer 3 makes voice output control signals through three I/O ports of P1.5, P1.6 and P1.7, and is connected with the voice output control circuit 8. Voice output control circuit 8 is composed of voice storage and control circuit 18 (U3) and speaker 19. The voice storage and control circuit 18 (U3) uses the TRS3BM10A voice chip, which stores 3 sections of voice in the TRS3BM10A voice chip, namely "keep the distance", "the light is too dark" and "take a rest". MCU 3 control. The loudspeaker 19 adopts an 8Ω loudspeaker device. The three pins A0, A1, and A2 of the voice storage and control circuit 18 (U3) are respectively connected to the three I/O ports of P1.5~P1.7, and the two pins P and N of the voice storage and control circuit 18 (U3) Pin is directly connected with loudspeaker 19. When P1.5 outputs a high level, the speaker emits the sound of "keep the distance", when P1.6 outputs a high level, the speaker emits a sound of "the light is too dark", when P1.7 outputs a high level, the speaker emits a sound of "attention rest" sound.

The whole system works with +5V power supply. The design of power supply and battery charge and discharge management 11 is relatively simple and practical. In actual normal operation, the system is powered by a lithium battery. The lithium battery 22 has used a 9V lithium battery that can be charged and discharged. The lithium battery outputs 9V through the voltage stabilizing block 26 to step down and stabilize the voltage to output +5V. The voltage regulator block 26 (U5) uses a low-dropout LM2940 voltage regulator chip. The positive electrode voltage of the lithium battery 22 passes through the working switch 24 and the electronic switch 25, and then is transmitted to the Vi input terminal of the LM2940 voltage regulator chip (U5). . Working switch 24 has used a toggle switch with 2 gears, cuts off the power supply output when dialing to the B end, connects the power supply when dialing to the A end. The electronic switch 25 uses a MOFET tube of the model SE2302. The gate of the SE2302 is controlled by the sampling circuit 23. The sampling circuit 23 uses a resistor and a 9013 transistor. One end of the resistor is connected to A of the working switch 24, and the other end of the resistor Connect directly to the collector of the transistor. When the collector output of the triode is low level, SE2302 is cut off; when the collector output of the triode is high level, SE2302 is turned on. The emitter of the triode is grounded, and the base of the triode is connected to the output end of the resistance-capacitance filter rectifier 20 through a resistor. The RC filter and rectifier 20 uses a resistor and a polyester capacitor in series for RC step-down, then uses 4 IN4001 diodes for rectification, and finally uses electrolytic capacitors for filtering and 12V Zener diodes for voltage stabilization to output 12V DC voltage. When the power cord and plug 2 of the eyesight protection prompter 1 are inserted into the AC 220V power socket, the electronic switch 25 is controlled by the sampling circuit 23 to disconnect instantly, and the voltage output of the lithium battery 22 is cut off, and the lithium battery 22 can be charged at this moment. The charging management of the lithium battery 22 is in charge of the battery charging management chip 21 (U4). When charging normally, the charging indicator 28 is on; if the battery is fully charged, the charging indicator 28 is off. After the charging is finished, the power cord and the plug 2 of the eyesight protection prompter 1 are pulled out, and the work switch 24 is shifted to the A end, and the work can be started.

The battery charging management chip 21 (U4) uses a rechargeable battery protection chip R5402N. As shown in Figure 7, the pins C _out and D _out of the chip are respectively connected to a MOFET tube SE2302 (Q1, Q2). When charging the lithium battery, the R5402N chip detects the voltage on the V _DD pin. When V _DD changes from low to high and exceeds the threshold voltage of the charging detector, it means that the chip detects overcharging at this time, the C _out pin outputs a low level, and the externally controlled N-channel MOSFET Q1 is turned off. When the lithium battery is discharging, the R5402N chip detects the voltage on the V _DD pin. When V _DD changes from high to low and is less than the threshold voltage of the discharge detector, it means that the chip detects over-discharge at this time, the D _out pin outputs a low level, and the externally controlled N-channel MOSFET Q2 is turned off.

In addition, a digital electronic clock timer is designed inside the system microcontroller to measure and compare the time. When the power is turned on, the startup system starts to work, and the internal timer/counter of the microcontroller also starts to count. When the timing reaches the preset value (such as 45 minutes), the single-chip microcomputer controls the I/O port P1.7 to output a high level, making the speaker 19 emit the sound of "pay attention to rest", reminding the reader to take a rest for a while, to relax the mind, so as to improve Learning efficiency.

This method of sampling can achieve high safety, that is, the battery is completely powered by low voltage when in use. If the power cord and plug 2 of the vision protection reminder 1 are plugged into the mains, the device will immediately cut off the internal power supply and stop the system. Work, do not supply power when charging, and do not connect to the mains and charge when powering, so that children and children are safe and reliable when using the device.

1. The connection method of each part of this embodiment is as follows:

The present invention combines a single-chip microcomputer 3 (U1), an ultrasonic transmitting circuit 4, an ultrasonic reflection receiving circuit 5, an illumination detection circuit 6, a key input circuit 7, a voice output control circuit 8, a battery voltage sampling 9, an undervoltage indication 10, a power supply and a battery charging The discharge management circuit 11 is designed and installed on the PCB circuit board, and is packaged with a shell to form the host of the microcomputer vision protection voice prompter 1, and the shell leads out a 220V AC mains power line and a plug 2. Insert the power cord and the plug of plug 2 into the power socket to start working.

2. The operation steps of this embodiment are as follows:

Insert the plug of the power cord and plug 2 into the AC mains power socket, and the device can start to work.

(1) Ultrasonic ranging settings. The K2 key can be used to set 5 levels of ultrasonic distance measurement and alarm. The minimum distance measurement alarm is 20cm, that is, the alarm "keep the distance" will be issued when the ultrasonic distance measurement is 20cm. If you press the K2 key once, the ranging alarm is 25cm; press the K2 key again, the ranging alarm is set to 25cm; press the K2 key again, the ranging alarm is set to 30cm; press the K2 key again, the ranging The alarm is set to 35cm; press the K2 button again, and the ranging alarm is set to 40cm; press the K2 button again, and the ranging alarm is set back to 20cm.

(2) Set the timing time. You can set 5 levels of timing and alarm through the K3 key. The minimum timing alarm is 30 minutes, that is, the alarm "take a rest" will be issued when the timing reaches 30 minutes. If you press the K3 button once, the timing alarm is 45 minutes; press the K3 button again, the timing alarm is set to 60 minutes; press the K3 button again, the timing alarm is set to 60 minutes; press the K3 button again, the timing alarm Set it to 90 minutes; press the K3 button again, and the timing alarm is set to 120 minutes; press the K3 button again, and the timing alarm is set back to 30 minutes.

(3) When L1 flashes, it indicates that the battery undervoltage is detected and the battery needs to be charged.

(4) When the illuminance is detected to be lower than 500lx, a voice prompt "insufficient light" will be issued.

(5) When the reading distance is detected to be less than the set value, a voice prompt "keep the distance" will be issued.

(6) When the detection and counting time reaches the predetermined value, a voice prompt "Pay attention to rest" will be issued.

Claims (10)

1. A voice prompter for microcomputer vision protection, which uses a single-chip microcomputer (3) as the core, including an ultrasonic transmitting circuit (4), an ultrasonic reflection receiving circuit (5) and an illumination detection circuit (6), and is characterized in that the single-chip microcomputer (3 ) is connected with the light intensity detection circuit (6) by the first I/O port control pin (P1.2) with A/D acquisition function, and the light intensity detection circuit (6) includes a photosensitive sensor (16) and a sampling circuit (17), The photosensitive sensor (16) and the sampling circuit (17) form a series circuit, and the connection point between the photosensitive sensor (16) and the sampling circuit (17) is connected to the first I/O port control pin (P1) of the microcontroller (3). .2), the first I/O port control pin (P1.2) is used as the signal input end of the A/D converter in the microcontroller (3). 2. The microcomputer vision protection voice prompter according to claim 1, characterized in that it further comprises a key input circuit (7), a voice output control circuit (8) and a battery voltage sampling circuit (9). 3. The microcomputer vision protection voice prompter according to claim 1 or 2, characterized in that: the chip of the single-chip microcomputer (3) has its own A/D converter inside, and the chip contains program memory, data memory and at least 11 I/O port control pins, at least 2 I/O port control pins have A/D acquisition function, and the chip of the single-chip microcomputer (3) has a built-in crystal oscillator. 4. The microcomputer vision protection voice prompter according to claim 3, characterized in that: the photosensitive sensor (16) is a LXD/GB5-A1DPH photosensitive sensor, and the sampling resistor in the sampling circuit (17) is 2KΩ. 5. The microcomputer vision protection voice prompter according to claim 1 or 2, characterized in that: the single-chip microcomputer (3) outputs ultrasonic signal waves through the second I/O port control pin (P1.0), and communicates with The input end of the ultrasonic transmitting circuit (4) is connected, the ultrasonic transmitting circuit (4) includes a drive circuit (12) and an ultrasonic transmitting sensor (13), and the ultrasonic signal is sent to the ultrasonic transmitting sensor (13) after being discharged by the driving circuit (12), Ultrasonic signals are emitted by the ultrasonic emission sensor (13). 6. The microcomputer vision protection voice prompter according to claim 1 or 2, characterized in that: the third I/O port control pin (P3.3) of the single-chip microcomputer (3) is used as an external interrupt signal input terminal and The output end of the ultrasonic reflection receiving circuit (5) is connected; the ultrasonic reflection receiving circuit (5) includes an ultrasonic receiving sensor (14) and an ultrasonic reflection demodulation circuit (15), and the ultrasonic reflection demodulation circuit (15) performs signal discharge large and limited Amplitude, band-pass filtering, wave detection, integration, and shaping are used as external interrupt signals and sent to the third I/O port control pin (P3.3) of the single-chip microcomputer (3). 7. The microcomputer vision protection voice prompter according to claim 1 or 2, characterized in that: the fourth I/O port control pin (P1.1) of the single-chip microcomputer (3) has A/D acquisition function The input end of the A/D sampling signal is connected to the battery voltage sampling circuit (9), and the battery voltage sampling circuit (9) is connected to the lithium battery (22); when the lithium battery (22) is discharged to a certain voltage value, the battery voltage The sampling circuit (9) collects the battery voltage value at this time and sends it to the single-chip microcomputer (3) for calculation and comparison processing. When the collected voltage value is less than the built-in battery discharge threshold V _t of the single-chip microcomputer (3), the single-chip microcomputer (3) passes The fifth I/O port control pin (P3.7) is connected to the under-voltage indicator light (10), and the under-voltage indicator light (10) flashes for warning for 1 minute and then automatically enters the power-down protection state. 8. The microcomputer vision protection voice prompter according to claim 1 or 2, characterized in that: the sixth, seventh and eighth I/O port control pins (P3.0, P3.1, P3.4) are respectively connected to 3 buttons (K1, K2, K3), and 3 buttons (K1, K2, K3) are connected to the button input circuit (7), among which: The first button (K1) is the reset alarm button, that is, after the first button (K1) is pressed, the timing alarm starts counting from zero, and when the count is equal to the preset time value, an alarm prompts "take a rest"; if After the time alarm is up, if the first button (K1) is not pressed, the timer will alarm every 5 minutes and prompt "Take a break"; The second button (K2) is the timing time setting button. There are 5 options for the timing time, which is a circular processing button: press the second button (K2) for the first time, the timing time is preset to 30 minutes, Press the second button (K2), the timing time is preset to 45 minutes, press the second button (K2) for the third time, the timing time is preset to 60 minutes, press the second button (K2) for the fourth time ), the preset timing time is 90 minutes, press the second button (K2) for the 5th time, the timing time is preset as 120 minutes, press the second button (K2) for the 6th time, the timing time returns to the preset time set to 30 minutes; The third button (K3) is the ultrasonic distance measurement setting key, with 5 options for ultrasonic distance measurement settings, which is a circular processing button: press the third button (K3) for the first time, and the ultrasonic distance measurement preset is 20cm , press the third button (K3) for the second time, the ultrasonic distance measurement preset is 25cm, press the third button (K3) for the third time, the ultrasonic distance measurement preset is 30cm, press the third time for the fourth time press the third button (K3) for the 5th time, the preset value of the ultrasonic distance measurement is 40cm, press the third button (K3) for the 6th time, the ultrasonic measurement The distance is back to the preset 20cm. 9. The microcomputer vision protection voice prompter according to claim 1 or 2, characterized in that: the ninth, tenth and eleventh I/O port control pins (P1.5, P1.6) of the single-chip microcomputer (3) , P1.7) as the voice output control signal terminal, connected with the three input ports (A0, A1, A2) of the voice output control circuit 8, the voice output control circuit (8) includes voice storage circuit and control circuit (18) and Trumpet (19). 10. The microcomputer vision protection voice prompter according to claim 1 or 2, characterized in that: it also includes a power supply and battery charge and discharge management circuit (11); the power supply and battery charge and discharge management circuit (11) includes a resistance-capacitance step-down Rectifier circuit (20), charging indicator light (28), battery charging management chip (21), lithium battery (22), sampling circuit (23), working switch (24), electronic switch (25), voltage regulator block (26 ), and ripple processing circuit (27).

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