E based on AT89C51SNDlC treatment instrument design

1 Introduction

Currently takes two electrodes tablets covered with the body parts of symmetry of electron treatment instrument, through the electrode voltage fluctuation on chip and the treatment of human parts resistors role in the treatment position produces human ability to sense the pulse of neuromuscular stimulation current, so that its systolic and diastolic, produce motion effects to achieve therapeutic purposes.

But the current market for this type of treatment instrument resulting ripple voltage of only a few, because of the ripple current frequency cycle fixation, if a treatment position long-term acceptance of the pulse could have the effect of treatment, causing spontaneous tension, reducing the treatment effect. To resolve this issue, the issue of random MP3 music signal into treatment instrument, so that the audio signal and 2.4 kHz frequency frequency of treatment for a variety of modulation, pulse voltage and frequency cycle constantly transform ripple current. They fluctuate along with the music signal and work, so that patients enjoy their favorite music while receiving treatment, distracting, relieve stress, which can help improve treatment outcomes.

Propose an approach based on embedded devices AT89C5ISNDlC electronic instrument design and spread D/A, mass storage, keyboard, display, implement basic MP3 function; control AT89C5lSNDlC produces audio and 2.4 kHz frequency signal, using a digital circuit complete both signal FM, zoom in, the transformer isolated output voltage pulse therapy.

2 works

Based on the embedded device 89C5lSNDlC electronic instrument system hardware structure shown in Figure l, divided into signal generation and control module, FM output modules, power modules, part 3.

Signal generation and control module is a massive memory microcontroller, 89C5lSNDlC, keyboard, USB port, LCD display, and D/A converters, audio amplifier.

When treatment instrument USB port into the computer's USB port, single-chip detection after U disk function, you can select the right MP3 songs are copied to the USB disk (instrument). When treatment instrument USB port not inserted computer USB interface, the instrument can be used as MP3 broadcast. Through the function keys set songs, treatment time, volume, start/stop key control treatment instrument. Treatment, the SCM has two inverted 2.4 kHz frequency signal frequency, F F if and an audio signal F audio, while at the same time will be stored in MP3 format songs decoded into audio digital signal, then by a D/A conversion amplifier, sent to the headset or loudspeaker.

Frequency modulation output module is FM, amplification, output dose adjustment and output transformers, electrode tablets.

Two-channel RP-if signals and one audio signal with frequency modulation, frequency modulation of the signal after enlargement, the output voltage of the transformer isolation output pulse, covered by electrode plate symmetric to the human body treatment position, the human body will feel with music fluctuating current stimulation. Through output adjustment, suit human dose different treatment position and skin stem humidity differences can bear aware of current requirements.

Power supply module provides 15 V, 5 V, 3.3 V system operating voltage.

When treatment instrument USB port into the computer's USB connector, single-chip implementation of U disk function, from computer USB interface provides + 5 v power supply. Therapy, physical therapy for the power supply is 220 V AC power supply via transformer, Rectifier, voltage, filters.

3 hardware system design

3.1 MCU introduction

Embedded device AT89C5lSNDlC set CPU, MP3 decoder, USB controllers, and other devices.

AT89C51SNDlC has 51 series single-chip microcomputer control and the ability to scale to MP3 and USB disk, using the PLCC packaging, its internal structure diagram shown in Figure 2.

AT89C5lSNDlC P0, P1, the P3 port features and compatible 5l series microcontroller, additionally increased the 8-bit P4 port, 4-bit port P5.

Clock circuit and the reset circuit connection method and 51 series microcontrollers.

The first time you use the devices need to separately download the USB driver, the user program.

64 in AT89C51SNDlC KBROM, address FOOOH-FFFFH is assimilated better Boot Loader code 4K bytes. The factory, the BLJB position 1, this power-up executed automatically after the Boot Loader code and wait for the download from the USB Flash disk driver or user programs target code. Once the download is complete, you should download the software will BIJJB position 0, again with electricity, to automate the user program. If you still need to modify the user program, you can reset the ISP pin low level. The power-on reset, the automatic boot Boot Loader code execution, wait for the user program. Restart the user should be ISP PIN reset to high level.

3.2 signal generation and control module

Signal generation and control module circuit diagram shown in Figure 3.

For MP3 and USB disk function, AT89C51SNDlC microcontroller need external a NAND Flash mass storage-, this selection of 16 MB of the data line K9F2808U0C I/I/00 ~ 07-P0 port, control line received P5 port. MP3 audio decoder output signals, and the MCU DOUT, DLCK, SCLK pin by DSEL, D/A converters CS4330, after enlargement, output to headphones listening to MP3 songs. LCD-MCU port P2, and keyboardMatching to display the current status of the instrument. There are four on the keyboard is pressed, the "volume/songs/timer" feature keys received P1.0 pin, respectively and P1.1 pin made of "next" button and the next P1.2 pin "previ-OHS" keys, to achieve the volume adjustment, song selection, treatment timing functions; and "start/stop" button then P1.3 pin.

AT89C5lSNDlC MCU P3.3 pin is used to detect the current using u disk or MP3 player.

If the treatment instrument USB leader received a computer's USB port, the detected P3.3 PIN reset, do u disk program, in which case the SCM jobs powered by the USB interface; otherwise, P3.3 pin detected low level, the implementation of the MP3 program. If signal F MF, MF and audio signal F F audio respectively AT89C5lSN — DlC MCU P4.4, P4.5 and DOUT PIN.

3.3 FM output module

Frequency modulation output module circuit schematic diagram shown in Figure 4.

Audio signal F audio separately and if signal F if and if phase modulation, producing two phase contrast modulation waveform, then by 9013, 8050, D880Y zoom evacuation to transformer two input terminals. Intermediate tapped voltage transformer by Ma table received dose adjustment circuit. 47 k Ω resistor that dose adjustment potentiometer, downwards then Ma table indicates the current smaller, but larger. Transformer isolated output voltage and input voltage synchronization changes. Output voltage through the electrode tablets and human contact, in the human body produces a perception of current. According to the physical location of different, and the extent of wet and dry skin, human perception-current. When you need to adjust the potentiometer physical therapy, physiotherapy, feeling comfortable.

3.4 power module

Therapeutic apparatus required 3.3 V, 5 V, 15 v supply voltage from the power supply module, its principle as shown in Figure 5.

3.3 V voltage can be supplied to the use of embedded devices AT89C51SNDlC; 5 V voltage can be supplied to the use of FM, amplifying circuit; 15 V voltage available to adjust the output dose. Of these, 5 V voltage used 78L05, V voltage used LDll17S33 3.3. When you use U disk function, physical therapy for the USB port of inserting PC USB interface, no 220 V AC power supply, single-chip voltage is supplied by the USB interface.

4 system software design

And hardware functionality, system software design process as shown in Figure 6; the keyboard interrupt service program flow as shown in Figure 7.

5 conclusion

Design of the portable device battery monitoring system using programmable battery monitoring chip BQ27210 and external high integrated processor C805lF304 on battery power, you can use time, temperature, voltage, and other information in real-time monitoring, and through an I2C bus for data transmission, with high precision and small size, low cost, has now been applied to some handheld data collection devices.