EEWorld invites you to dismantle (Issue 7) - Dismantle the weight loss tool - Preliminary dismantling

吾妻思萌

EEWorld invites you to dismantle (Issue 7) - Dismantle the weight loss tool - Preliminary dismantling [Copy link]

 

After using it for about ten days, I started to disassemble it today. The overall experience is good. I lost 0.5 kg by exercising with gritted teeth, and gained it back by eating with gritted teeth.

It can be said

Love and money may fail you and leave you, but fat will never.

----Wo Ziki Shuode (poet, social activist)

Since it needs to be disassembled, tools are indispensable. It seems that a screwdriver can be used to do it first.

• Skipping rope handles in mint condition.

• Unscrew the screws at the back and easily remove the control back panel.

• Take a close-up of the power board and you can see that the CR2032 button battery holder takes up a lot of space, and then there is the JU308 packaged direct-insert crystal oscillator. The black one at the bottom is the buzzer, which beeps every time you turn on the machine.

• The front is the so-called cow dung chip in the center, which takes up a large area, with four buttons below, some capacitors and resistors, and two Hall sensors on the top.
• So we know that the way to count when skipping rope is that there is a rotating magnet on the top. When we jump rope, the magnet rotates, thereby generating a changing magnetic field. The Hall sensor captures the change in the magnetic field and then counts.

• Then there is a family portrait, and basically everything that can be dismantled has been dismantled.

Under comprehensive evaluation

Modules	effect	design	Comments from an engineer's perspective (just my personal preference)
power supply	System power supply	Use button battery	It is replaceable, simple and practical, but if it can use small batteries and solar panels, similar to the computer solution, it may be more environmentally friendly.
control	User Interaction	Buttons	The long and short presses for turning the machine on and off are almost standard, and the UP and DOWN buttons are also designed to be accelerated by long presses. It's just that there is no manual. When promoting the product to the public, remember not to have preconceived engineer thinking. I think everyone knows everything, but in fact, everyone knows nothing.
count	Skipping Rope Count	Magnetic field change counting	The magnetic field change solution is good and is more drop-resistant than optical or mechanical solutions. Optical solutions have high requirements for alignment, while mechanical solutions are easily damaged or displaced, and the cost is also high.
show	Display Status	Pen Duan LCD screen	It's small, has everything it should have, has a clear display, plenty of backlight, and the LED diffuser is OK, with no flaws.

This is the end of the preliminary disassembly. The next step is to remove the "bull dung" vinyl chip, which is more difficult to remove and is basically destructive.

吾妻思萌

A family should be neat and tidy

Honghuzaitian

OK, the basic principle has been explained clearly, but can you still pull out the chip to see it?

秦天qintian0303

Why is the chip sealed with glue? Are they afraid that others will see what chip he uses?

zhangjsh

Qintianqintian0303 posted on 2022-11-26 07:10 Why is the chip still sealed with glue? Are you afraid that people will see what chip he uses?

The main control chip is a dog skin plaster chip with low price, which is conducive to reducing BOM cost.

btty038

Bull shit chip

wangerxian

How does the display light up? It looks like a transparent glass cover.

dcexpert

The cost is maximized

tagetage

I lost 0.5 kg in weight - it's just a matter of drinking one less bottle of beer...

秦天qintian0303

zhangjsh published on 2022-11-26 08:31 The main control chip is a dog skin plaster chip with low price, which is conducive to reducing BOM cost

So they stopped working because they were afraid of losing talent?

吾妻思萌

I don't think so. Sealing glue can provide protection from water and dust, and the cost is low. It is actually a good design.

吾妻思萌

wangerxian posted on 2022-11-26 08:39 What is the lighting principle of that display? It feels like a transparent glass cover.

It is a normal segment display screen with a conductive rubber

There are contacts on the PCB

吾妻思萌

Qintianqintian0303 posted on 2022-11-26 07:10 Why is the chip still sealed with glue? Are you afraid that people will see what chip he uses?

It plays a protective role, and the sealing glue also costs money

Besides, these glue de-caps can also be opened.

wangerxian

Azuma Simeng published on 2022-11-28 17:31 It is an ordinary segment code display screen with contacts on a conductive rubber PCB

Oh, I thought it was a screen.

zhangjsh

This chip is shipped as a bare die and then mounted on the chip by the customer. It is also called "soft package"