A comprehensive disassembly of the Internet celebrity fascia gun: the counterattack of the national chip production plan

The fascia gun drives a series of structural devices to produce a "thump thump" movement through the operation of the motor, just like simulating repeated punching with a small fist, commonly known as body training. As a hardware engineer, when you see this kind of movement, there is no doubt that its principle is not even as complicated as an electric screwdriver.

So what is the working principle of the fascia gun that makes it "thump, thump, thump" so simple and crude? Disassembly will reveal the answer!

Disassembly

The product disassembled in this issue is the fascia gun made by JD.com.

After disassembly, only the handle with the battery is left; the core brushless motor with the driver board; the switch power supply and charging board; the control board and a bunch of debris.

The battery in the handle is fixed by glue, which makes it troublesome to remove and there is nothing to see, so it is not disassembled further. There are 6 green LEDs on the main power switch and charging board. The charging interface is simple and direct, so there is no special circuit on this small board.

The core brushless motor is a domestic motor, Dongguan Guomeng Motor (BL4020). As we all know, the motor only rotates itself, so how to achieve the "thump thump" reciprocating motion on the fascia gun? There is an important structure here, one is the eccentric wheel with the motor, then the connecting rod on the eccentric wheel, and the fixed sleeve.

When the motor turns, it converts the original circular motion into linear reciprocating motion (you can watch the video to see the actual demonstration process).

Therefore, to really judge the quality of a fascia gun, in addition to the drive control circuit itself, the life of the motor, the strength of the connecting rod, etc. are all very important. For example, the connecting rod here is solid. Although this is relatively reliable, it is heavier than the hollow one. Especially when a girl holds a heavy fascia gun to do relaxation exercises, the weight of the fascia gun itself will also affect the experience.

Finally, the control board is also very simple. The 78L05 voltage regulator steps down the battery voltage and outputs a 5V voltage to power the microcontroller. The microcontroller is a domestic Saiyuan enhanced 8051 core (SC92F8362B), which has a 23-channel low-power capacitive touch circuit, so it can seamlessly realize the 3 touch control buttons on the fascia gun. In addition, this microcontroller also integrates 6 independent PWM signals, so it can directly realize the control of the brushless motor.

summary

The fascia gun simulates compression through high-frequency impact to achieve the so-called physical therapy, but its core working principle is simple and crude, "fighting violence with violence". Most fascia guns on the market are eye-catching in appearance, and the prices range from hundreds to thousands. Especially now, many Internet celebrity products are not as good as their reputation.

After reading the circuit solution of JD.com's fascia gun, I was not surprised that it was almost the same as expected. The circuit solution and structure were relatively simple and there was nothing creative about it. However, what was more surprising was that this was actually a completely domestically produced chip solution. The microcontroller, brushless motor, voltage regulator, etc. were all domestically produced chips. In this internet celebrity product, domestically produced chips have made a comeback.