Where is the intelligence of the smart power strip? Take it apart and take a look

If today's home appliances didn't have the word "smart" in them, would you still consider them? Smart TVs, smart water heaters, smart washing machines, smart refrigerators, and even the power strips we often use are smart. Why does a small power strip need to be smart? What are the differences and advantages between it and ordinary plug-in strips? Today, we have selected three smart power strips for disassembly and analysis. I believe you will be able to find the answer.

Produced by Electronic Engineering World (ID: EEWorldbbs)丨

1. Overview

2. Appearance and experience
1. Exterior

2. Ordinary power strip usage experience

• remote control

Figure 2-4 Mijia App (left), disconnection (middle) and connection (right) of the control socket hole/USB charging port/main switch

• Electric energy monitoring and power measurement

• Timer/countdown switch

• Electric energy measurement test

Figure 3-1 A smartphone with a charging power of 10W (10W, left), a PD charging head with a 65W rated power (65W, middle), and a TV with a 180W rated power (measured about 155W, right)

• USB-PD fast charging test

Figure 3-2 PD decoy testing USB-C output voltage

Figure 3-3 PD tester tests USB-C output voltage (reprinted)

Figure 3-4 Insert the 65W fast charging PD charging head into the socket hole to charge the laptop (about 65W)

Figure 3-5 Directly use the USB-C1/C2 fast charging PD charging port to charge the laptop (about 65W)

• Mechanical structure and socket

Figure 4-1 Plug and jack shield

Figure 4-2 The position of the jack baffle changes during insertion

• Circuit board structure with strong and weak electrical isolation and insulation

Figure 4-3 Back panel and PCB backside

Figure 4-4 Housing and PCB front

• High current part (relay on and off sub-control, metering)

Figure 5-1 Front side of metering circuit PCB

Figure 5-2 Measurement circuit PCB back side

Figure 5-3 Front side of socket circuit PCB

Figure 5-4 Back side of socket circuit PCB

Figure 5-5 Relay circuit

Figure 5-6 Front side of strong and weak circuit PCB

Figure 5-7 Back side of strong and weak circuit PCB

Figure 5-8 IoT module small board

Figure 5-9 Fast charging small board PCB front

Figure 5-10 SW3518 fast charging circuit solution

TODO-List：

• Reverse restoration and DIY design of some circuits (TODO)

Strong electricity part (DIY a smart power strip with BLE/WIFI remote control and energy measurement)

Although this part of the circuit is located in 220V strong current, the metering and relay switching can be developed and debugged under the isolated power module. After debugging, the isolated power module is replaced with a 220V to 3.3V KP35026 circuit. After ensuring that the KP35026 After checking the reliability of the circuit part, you can try to DIY this part of the circuit at least while isolating the power module.

• Conversion between strong and weak electricity (no experience, will not do it)

I have only learned simple theories in this part, but have no practical experience, and do not have professional development tools and testing instruments. I can only talk on paper. I cannot risk casually connecting to 220V for switching power supply design. Otherwise, the consequences will be disastrous, ranging from the board to the core. In severe cases, electric shock may result in injury or even more serious consequences.

• Weak current part (DIY a PD fast charging module)

The PD fast charging module of this row uses the SW3518S solution of Zhuhai Zhirong. There are many popular products on the market using this solution. After inquiries, many DIYs adopt this solution, and you can also find such chips. and modules are sold, so you can DIY a PD fast charging module based on SW3518S.

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Disassemble the Xiaomi fast charging plug board

Original post address: https://www.eeworld.com.cn/abfbTSG

What I’m disassembling today is the Xiaomi fast charging power strip. This power strip is different from the previous power strip in that it has three additional USB sockets. Nowadays, there are many small devices powered by USB in daily life, and this kind of power strip is also a trend of social development.

This is the online price and sales are pretty good. Pictures of samples received:

It's ready to be disassembled. Remove the rubber pads at the four corners and you can see the screws hidden inside .

It's this triangular shape. I couldn't find this kind of tool at home. I found a set at the company and finally took apart the outer casing. It is surrounded by snap structures and the workmanship is quite good.

Large picture of small board details:

The silk screen of the original control IC is 83411, but no specifications can be found. There is no specification sheet for the USB current limiting IC either. The secondary side synchronous rectifier IC was found to have a weak glow.

Here's another big picture of the plug-in: using solid capacitors, it can be considered a conscientious product.

As I write this, the disassembly is almost complete. Let’s put it back together and power on for a look.

The key switches are also illuminated for easy operation at night. Summary: Since the introduction of male strips, I feel that the quality of China's strips has gone up to a higher level, many times better than before. This power strip is very good in terms of appearance and safety. Fully meets general household use. Personally, I feel that if the internal copper bars and pins are plugged in, there will be poor contact, and will it cause heat and burn out the socket.

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Sunflower P1 power strip disassembly

Original post address: https://www.eeworld.com.cn/aybzv9C

In the era of smart homes, epidemics have been recurring. I believe that working from home is no longer strange for workers. Speaking of working from home, it is not an easy task. For programmers, the software development environment and hardware debugging environment are both in the office. It is very troublesome and unnecessary to re-establish the environment at home. In the era of technology, if you want to be comfortable at home Of course, there are simpler ways to work.

I am honored to participate in this Sunflower brand smart power strip P1Pro disassembly event. After two weeks of actual use experience, I would like to share my feelings with you. This sharing will start with ① disassembly background before disassembly; ② unboxing process; ③ display of special functions; ④ usage experience.

1. Background of disassembly

Disassembled product: Sunflower P1pro power strip

Specifications:

It can be seen that remote switch, 4-hole independent control, and power measurement are the main features of the product. The 2500W power and 2-meter cable length can also meet the needs of most daily scenarios.

2. Unpacking process

When I got the dismantled product, it was packaged in a black box with a very simple logo printed on it and a layer of dust-proof plastic film on the outside.

Take apart all the products inside as shown below

When I saw this all-black power strip and simple logo, my first impression was that it was full of technology. The five-position jacks on the power strip are all designed with protective doors to effectively prevent foreign objects from being inserted.

The outer casing of the wiring board is made of 750℃ high temperature flame retardant material, which provides sufficient electrical safety guarantee in complex and harsh usage environments.

On the reverse side are some parameters. You can see that the power strip has passed the national 3C standard certification. There is also a 3C certification mark on the plug, which is very safe in terms of electrical safety.

The bottom of the wiring board is designed with multiple anti-slip pads, making it very stable when placed on the desk. In addition, there are fixing holes at the bottom of the wiring board, which can also be fixed to the wall.

The blue power light and white sub-control indicator light after power-on feel very good and clear.

3. Demonstration of special functions

Next comes the key point, about the remote control function of this Sunflower power strip combined with the Sunflower APP and its power metering function. This is the part I am most looking forward to.

First, open the manual and follow the steps to download a Sunflower remote control APP on your mobile phone. After opening the APP, first power up the power strip, then add smart hardware to the APP, and you can search for our power strip through Bluetooth.

Then follow the prompts to configure the network for it. The first time you configure it, it fails. It prompts that it only supports 2.4G WiFi. Then turn off the multi-band integration in the home router and create a separate 2.4G WiFi. solved this problem.

After successfully connecting the power strip to the network, you can check the status and control it through the app on your mobile phone.

Through this control panel interface, you can basically see all its main functions: four switch buttons independently control the on and off of each row of jacks, and the switches can modify notes; power statistics; binding to the host; countdown/timing.

Click on the power statistics function interface, which includes current current, power consumption, power usage duration, number of switches and power consumption statistics modules. I plugged in a 20W mobile phone charger to charge the phone, and the power consumption displayed was 19.71W, which is basically accurate. Regarding the accuracy of daily electricity consumption, it is impossible to test its accuracy because there are no measurement tools in this area.

Regarding the countdown/timing function, I think this function is very easy to use and flexible. You can add a scheduled shutdown function to some home appliances or equipment that do not have a scheduled shutdown function, and certain scenes can also have regular timing switches.

The next thing I want to focus on is its main highlight function. It can be used with the Sunflower remote control software to remotely control the computer that is turned off at any time.

I believe everyone is familiar with Sunflower remote control software. We often use this similar software to remotely control computers in remote locations. For example, when working from home, you need to use files on the company's computer, but the company's computer is unlikely to be turned on all the time, which consumes a lot of power and poses a security risk. In this case, you can use the Sunflower power strip to software the computer. Power on, turn on the computer (the computer must be set to power-on auto-start mode), and then use remote control software to complete various operations. After connecting the computer power supply to a jack, you can bind the jack to the corresponding host in the APP, so that you can easily control the computer's switch in the APP.

In addition, in some engineering application scenarios, if the computer crashes and needs to be restarted, but it is inconvenient to arrive at the scene, the computer can also be restarted remotely through the power strip.

4. Use experience

After two weeks of use, the overall feeling is quite good. Compared with other smart power strips that use voice control with voice assistants, the highlight of this power strip is remote control. In addition to its good appearance, powerful functions, and flexibility, there are also some small details that are also very good. For example, its rows of jacks are widely spaced, so there will be no interference between plugs in actual use; Power recovery function, after a call comes, the plug can maintain the state before the power outage. With such functions, the price is less than a hundred yuan, even cheaper than traditional wiring boards, which can be regarded as a highlight.

This disassembly is mainly carried out from several aspects: disassembly process, circuit structure, and introduction of main circuit chips. Without further ado, let’s get straight to the point.

1. Disassembly process

First, use your hands to peel off the anti-slip pads on the four corners of the back of the strip, and you will see the fixing screws, which are Y-shaped screws.

After using a small word to slowly pry it open along the edge, you can clearly see that there are five inner buckles on each side.

After taking it apart, the first thing that comes into view is the bottom of the circuit board. You still need to unscrew the four screws that fix the circuit board and the two screws at the cable inlet before you can fully see the front of the circuit board.

2. Circuit structure

1. Overall circuit structure

Observing the front of the circuit board, it can be divided into several parts: voltage reduction part, main control switch part, power metering part, linear voltage stabilizing part, main control chip part, four groups of socket bases, four groups of relay control modules, four groups of indicator light

2. Partial structure of the socket

There is a light guide column next to each socket to better display the SMD LED lights on the circuit board on the panel.

3. Introduction to main circuits

1. Master control switch part

The common four-cornered square button is surrounded by 4 LEDs and a ring-shaped light guide column to achieve the effect of a color-changing light ring on the button part.

2. Pressure reduction part

BiMicro's KP3116 high-performance, low-cost offline PWM control power switch chip is used.

KP3116 is a high-performance and low-cost PWM control power switch, suitable for offline low-power step-down applications.

• Different from traditional PWM controllers, KP3116 does not have a fixed clock inside to drive the MOSFET, and the system switching frequency can be automatically adjusted as the load changes.

  
  

• The chip's internal peak current detection threshold can be automatically adjusted according to the actual load condition, which can effectively reduce standby power consumption under no-load conditions.

  
  

• Integrated complete protection functions with self-recovery function: VDD under-voltage protection, cycle-by-cycle current limit, abnormal over-current protection, output over-voltage protection, over-heat protection, over-load protection and VDD over-voltage protection, etc.

3. Electricity measurement part

The metering chip uses Shanghai Belling's BL0937, which is a metering chip specially designed for smart sockets.

• High accuracy, within the input dynamic working range of 2500:1, the nonlinear measurement error is less than ±0.5%

• The chip has an anti-creep design to ensure noise power is cut off when there is no current.

• Small signal stability, sampling current 50mA point CF jitter is less than ±0.3%

• The chip has built-in oscillator circuit, clock is about 2MHz

• There is no need for complicated communication protocols with the MCU to read the metering chip registers in real time, and the metering accuracy calibration is relatively simple. You only need to calibrate the coefficients at rated power load, and no complicated calibration equipment is required.

4. Relay part

The Aifu BJ-SS-105DMF relay is used

5. Main control part

The main control chip uses Espressif’s ESP32-C3-MINI-1

It is a safe, stable, low-power, low-cost IoT chip equipped with a RISC-V 32-bit single-core processor. It also supports 2.4 GHz Wi-Fi and Bluetooth LE 5.0, providing industry-leading radio frequency for IoT products. performance, complete security mechanisms and abundant memory resources. ESP32-C3's dual support for Wi-Fi and Bluetooth LE 5.0 reduces the difficulty of device network configuration and is suitable for a wide range of IoT application scenarios.

6. Voltage stabilization part

The voltage regulator chip uses Weir's WL2803E33-5/TR, a linear voltage regulator commonly used in smart sockets.

4. Summary

After disassembling this power strip, I feel pretty good. First of all, the workmanship is good, and the internal materials are very solid. Secondly, the layout is reasonable, the modularity is strong, and the circuit structure is clear at a glance. There are some small highlights, such as the control chip placed on the right end far away from the buck module, and key positions have repair welding to increase the ability to pass large current.

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After reading the above disassembly, do you have a new understanding of smart power strips? Will your next power strip be a smart one?