Schematic diagram of microcomputer low-frequency electrotherapy instrument

The low-frequency pulse current of the microcomputer low-frequency therapy device mainly has three physiological and therapeutic effects: 1. Exciting neuromuscular tissue 2. Promoting local blood circulation 3. Analgesia. In recent years, many low-frequency therapy devices have appeared on the market. This circuit can output various massage techniques that simulate human hands, with adjustable intensity and a variety of modes to choose from. Various components are common components on the market, and the inductor is a common color ring inductor. It is best to use a patch dedicated to the therapeutic device for output. As shown in the picture, the chip uses Elan's EMC78P156, and the power supply can be powered by three batteries. Working principle: In the circuit, the P5.0 and P5.1 ports of EM78P156 are used to control waveform changes, P5.2 is used to drive the boost circuit, and P5.3 is used to receive the signal of the automatic stop circuit without output. To automatically enter the SLEEP state. P6.0 to P6.3 are used for button detection, and P6.4 to P6.7 are used for mode display. The circuit is divided into four parts. 1. The control circuit is composed of buttons, microcontroller, and indicator lights. Press the corresponding button, the corresponding function output, the indicator light lights up, and the mode is adjustable. When the indicator light is used in multiple modes, it is used to display the current mode. of. The intensity is adjustable. Generally, the output intensity should be tolerable and should not be too strong. 2. The boost circuit outputs a square wave with a certain pulse width and frequency at the P5.2 port to put Q1 in the switching state. The power supply passes through the boost circuit composed of L1, Q1, D1, and C1. A voltage several times higher than the power supply is produced. There is no need to keep outputting the signal and keep it boosting. You only need to boost the voltage before the moment of output. After stopping the output, the boost circuit stops. If you want to increase the intensity, just widen the output signal time. For example, in the first level, the signal output is 1MS, and in the second level, the signal output is 2MS. The second level will be much stronger than the first level. It is recommended that the intensity should not be changed. If it is too big, strengthen it little by little, otherwise, the human body will be unbearable. 3. When the waveform control and output circuit outputs, first let the boost circuit work to boost the voltage, and then P5.0 and P5.1 are output respectively (note, the two ports cannot be output at the same time). When outputting, P5.0 and P5 .1 The output waveform is the same, but the phase difference is 180 degrees. In this way, you can get the same feeling at the output end of both output terminals. There will be no phenomenon where only one port has feeling and the other port has no feeling. In these two ports, you can control the on-off of the output circuit and the voltage of the above boost circuit to simulate various massage techniques. You can also refer to the modulation medium frequency, dense wave, sparse wave, and intermittent rise in "Physiotherapy" Waveforms such as waves are used to produce therapeutic functions such as analgesia and weight loss. 4. No output automatic stop circuit. This circuit is when the output has no load, no current flows through D3 and D4, and there is no voltage drop on them. Q6 has no base voltage and is in the cut-off state. The P53 port gets a high level. If the high level time exceeds 5 seconds, it means there is no load and it will stop automatically. If there is a load and current flows, D3, D4 and Q6 have base voltage and are in the conduction state. Port P53 gets a low level, which means there is a load. . This is the basic principle of the low-frequency therapeutic device. Next time, we will discuss its program flow and the human body's feelings about different waveforms. What kind of waveform has a therapeutic effect on the human body.