At present, two electrode slices are symmetrically covered with the treatment of the human body portion, and the pulsating voltage on the electrode sheet is generated by the resistance of the human body, and the human body can be perceived, and the neuromuscular can be stimulated and contracted. Droupless, producing motion effects to achieve the purpose of treatment. However, there is only a few of the pulsating voltages generated by this type of treatment in the market. Since the pulsation current frequency period is fixed, if a treatment site has long been tested for a long time, it will cause anti-therapy effect, causing spontaneous tension, thereby reducing the treatment effect. In order to solve this problem, the random music signal emitted by MP3 is introduced into the aater, and the audio signal is modulated with the center frequency treatment frequency of 2.4 kHz, producing a plurality of pulsating current and frequency cycles constantly transform pulsation current. They have an effect of rising the rolling of musical signals, allowing the patient to receive treatment, decentral attention, relieving tension while enjoying the music, and relieving tension, thereby helping to improve the treatment.
A electronic treatment instrument design scheme based on embedded device AT89C5ISNDLC is now expanded to D / A, mass storage, keyboard, display, realizing basic MP3 function; control AT89C5LSNDLC generates audio and 2.4 kHz intermediate frequency signal, using digital circuits to complete The frequency modulation of these two signals, after an enlargement, by the transformer isolation output pulsation therapeutic voltage.
1 Working principle
The electronic therapeutic device system based on the embedded device 89C5LSNDLC is shown in Figure 1, which is divided into signal generation and control module, the frequency modulation module, and the power module 3.
The signal generation and control module consists of 89C5LSNDLC microcontrollers, massive memory, keyboard, USB port, liquid crystal display, D / A converter, audio amplification and other parts. When the USB port of the therapy is inserted into the USB interface of the computer, the U disk function is performed after the single-chip detection, and the selected MP3 song can be copied to the U disk (therapeutometer). When the USB port of the therapy is not inserted into the USB interface of the computer, the treatment instrument can be an MP3 broadcast. Set the song, treatment time, volume, and control the therapy by start / stop the key by function key. When treatment, the single chip generates two inverted 2.4 kHz intermediate frequency signal F intermediate frequency, F ratio and an audio signal F audio, and the stored MP3 format is decoded as an audio digital signal, and then amplified by the D / A conversion amplifier, Send to headphones or speakers.
The FM output module is composed of frequency modulation, amplification, output dose adjustment, output transformer, electrode sheet, and the like. The two-way intermediate frequency signals and all the audio signals are modulated. After the frequency modulation is amplified, the output pulse voltage is separated by the output transformer, and the electrode sheet is symmetrically covered into the human body treatment site, and the human body is perceived with music fluctuations. Current stimulation. Differentiated by the output dose adjustment, satisfying the different treatment sites and the dry humidity of the human body can withstand a perceived current.
The power module provides 15 V, 5 V, 3.3 V system operating voltage. When the USB port of the therapy is inserted into the computer USB interface, the microcontroller performs a U disk function, and the power supply of +5 V is provided by the computer USB interface. When treating, the power supply of the therapy is generated by the AC power of 220 V by transformer, rectification, regulator, and filtering.
2 hardware system design
2.1 MCU Introduction
Embedded Device AT89C5LSNDLC Sets CPU, MP3 decoder, USB controller and other devices. AT89C51SNDLC has a control function of a 51-series microcontroller, but also scalable to MP3 and U disk, which uses a PLCC package, and its internal structural block diagram is shown in Figure 2.
The P0, P1 and P3 port functions of AT89C5LSNDLC are compatible with 5L series microcontrollers, and additional 8-bit P4 ports, 4-bit P5 ports. Clock circuit and reset circuit connection method with 51 series single chip.
Use this device for the first time, you need a USB driver, the user program. In the 64 KBROM of AT89C51SNDLC, the address foooh-fffh has been simplified in the 4k byte boot loader code. When the factory is shipped, the BLJB position has been 1, so that the boot loader code is automatically executed after power-on, waiting for the U disk U disk driver or user program target code from the USB interface. After completing, the BijJB position should be 0, and the user program is automatically executed again. If you still need to modify the user program, you can set the ISP pin low. After power-on reset, the boot loader code is automatically boot, waiting to update the user program. Restart the user program, you should set the ISP pin to high.
2.2 Signal generation and control module
The signal generation and control module circuit principle is shown in Figure 3. In order to implement MP3 and U disk functions, the AT89C51SNDLC microcontroller needs to be external to a NAND-Flash mass storage, where 16 MB of K9F2808U0c is selected, and its data lines I / 00 ~ I / 07 connect the P0 port to control the line P5 port. MP3 audio decoding output signal, while the single-chip DOUT, DLCK, DSEL, SCLK pin connector D / A converter CS4330, enlarged, output to the headset to listen to MP3 playback. The LCD screen is connected to the P2 port of the single-chip microcomputer, with the keyboard to display the working state of the current therapy. There are 4 buttons on the keyboard, "Volume / Song / Time" function key P1.0 pin, "Next" and P1.2 pin connected to P1.1 pin, "Previ-OHS) "Key to match, realize volume adjustment, song selection, treatment timing, etc." Start / Stop "key P1.3 pin.
The P3.3 pin of the AT89C5LSNDLC microcontroller is used to detect the current U disk or the MP3 player. If the USB lead of the treatment instrument is connected to the USB port of the computer, the P3.3 pin detects a high level, performs a U disk program. At this time, the working power supply of the microcontroller comes from the USB interface; otherwise, P3.3 pin If the low level is detected, the MP3 program is executed. The intermediate frequency signal F intermediate frequency, F ratio and audio signal F audio separately connects P4.4, P4.5 and DOUT pins of the AT89C5LSN-DLC microcontroller, respectively.
2.3 FM output module
The schematic diagram of the FM output module circuit is shown in Figure 4. The audio signal F audio is modulated with the intermediate frequency signal F ratio and the intermediate frequency, generating two phase opposite modulated waveforms, and then transmitted to the two inputs of the transformer after 9013, 8050, D880y amplified. The intermediate tap voltage of the transformer can be adjusted by the dose regulating circuit connected by the milliam. 47 kΩ potentiometer is a dose regulatory potentiometer, down-regulation, and the current change of the milliam table indicates, and it will become large. Transformer isolation output voltage change is synchronized with input voltage. The output voltage is contacted with the human body with the human body, and a perceived current is generated in the human body. According to the differentness of the physiotherapy site, the perceived current of the human body is different from the degree of dry wet. The treatment of the potentiometer is required to make the physiotherapy feel comfortable.
2.4 Power Module
The working voltage of 3.3 V, 5 V, and 15 V of the treatment instrument comes from the power module, and the principle is shown in Figure 5. 3.3 V Voltage can be used to embedded device AT89C51SNDLC; 5 V voltage can be provided to the frequency modulation, amplifying circuit use; 15 V voltage can be supplied to the output dose regulating circuit. Among them, 5 V regulator uses 78L05, 3.3 V regulator using LDLL17S33. When using a U disk function, the USB port of the therapy is inserted into the USB interface of the computer, and the 220 V AC power is not connected, the single-chip operating voltage is provided by the USB interface.
3 system software design
With the hardware circuit function, the system software design process is shown in Figure 6; the keyboard interrupt service program flow is shown in Figure 7.
4 conclusion
The design of the portable device battery monitoring system utilizes the programmable battery power monitoring chip BQ27210 and the external high integrated processor C805LF304 realize real-time monitoring of information such as battery power, time, temperature, voltage, etc., and transmits data through the I2C bus. Treatment, high, small size, low cost, etc., is now applied to some handheld data acquisition equipment.
Source: Wiku Electronic Market Network
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