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Teardown Action LSC Smart Power Strip 3202887 AL E24748 CB3S - 4 independent switchable sockets

mtb1007 1863 8
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  • As sold in the Action stores (NL, Dec 2024). First some images:

    Packaging of the LSC Smart Connect smart power strip with WiFi functionality.

    Packaging of a power strip with four sockets and a button.

    White power strip with four outlets and a power plug.

    The device can be successfully used with OpenBeken, but requires some DIY skills to open the housing without damage.

    BIG FAT WARNING: the electronics inside the power strip are directly connected to the 230V mains lines, without any isolation!
    Keep the mains plug disconnected during the whole operation!

    First, remove the 8 rubber feet (they pull out very easily):
    Back side of a power strip with eight screw holes and an informational label.

    Next, you'll find screws with a completely flat head surface. For the rest, they are normal self-tapping plastic screws:
    Self-tapping screw with a round head on a white background.

    So, how to get them out? As first attempt, I tried to drill them out. This ruined the plastic housing around the screws so badly, that it was almost impossible to reassemble the power strip again.

    The second plan worked better: get an (old) metal drill bit (ca 4 mm diameter) and an electric grinding stone. Grind down the head of the drill bit, and create an 'opposite' cutting surface. In other words, let's create a left-turning drill.

    Drill bit with a custom ground tip for unscrewing screws Drill bit with modified tip for screw removal.

    Stick some tape around the drill, so it won't damage the 'shaft' of the screw hole with its sides (we only need the tip of the drill).
    Carefully place the drill in the center of the screw head, so it doesn't touch the side walls. Start drilling (counterclockwise of course) and keep the drill centered, away from the sides.
    At first, the drill will start eating some of the screw head, that's fine. At some point it will get enough grip, so that it starts turning the screw. Once the screw gets halfway out, the drill is more likely to hit the side walls, so keep it centered!

    Once the screws are out, the inside shows some wiring strips, a mains-powered PCB with 4 miniature relays and a CB3S module, and a separate PCB strip along the sockets, which holds the 4 LEDs:

    Open plastic casing of a power strip showing internal electronic components and wiring.

    Note the grooves in the ball joint at the end of the cable. When reassembling the housing, this groove must point straight up and down, so they align with two notches in the housing halves.
    Interior of power strip with CB3S module and wiring.

    Make some temporary solder connections to the 1st, 2nd and last pin of the top row, and the last pin of the bottom row:

    CB3S module with soldered wires.

    And connect them to a 3.3V TTL serial interface:

    Interior of a power strip with a connected USB to TTL interface.

    Colors don't matter, but in these pictures:
    - black: Gnd
    - red: +3.3V
    - purple: Tx (smart plug) to Rx (PC)
    - yellow: Tx (PC) to Rx (smart plug)

    Some hints for flashing OBK:
    - When the flashing software asks for a device reset, you can shortly pull and re-plug the red wire.
    - This didn't work reliably for me. Instead, you can also momentarily connect pin 1 of the CB3S module (its reset input) to Gnd:

    Top view of CB3S module with pin markings.

    Device configuration:
    Code: Text
    Log in, to see the code

    As JSON:

    Code: JSON
    Log in, to see the code

    Finally: when reassembling, use normal screws :-)
    I used 'tapping screws 2.9x16mm', but 2.9x13mm will probably also fit fine.

    Cool? Ranking DIY
    About Author
    mtb1007
    Level 2  
    Offline 
    mtb1007 wrote 2 posts with rating 10. Been with us since 2024 year.
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  • #2 21361190
    p.kaczmarek2
    Moderator Smart Home
    It's certainly an interesting device, I don't remember seeing an Action-branded power strip yet. By the way, you can also script the button to control each of the socket on given single click, dbl click, triple click, etc, event. See our autoexec.bat examples here:
    https://github.com/openshwprojects/OpenBK7231T_App/blob/main/docs/autoexecExamples.md
    You can also enable powersave 1 on your device. It might reduce heating a bit and maybe prolong the life of power supply...
    Helpful post? Buy me a coffee.
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  • #3 21361474
    gulson
    System Administrator
    I will post here an interesting comment from Facebook under the article:
    "A hint perhaps obvious, but explaining why the circuit may "not reset" when Vcc is unplugged. Namely, the high state on the Tx line of the converter flows through the input pin of the circuit to the power supply. Another non-obvious suggestion to readers, if such equipment is plugged into AC while programming or debugging - use a galvanic separator. The USB type is popular. And do not touch the side of the strip with your hand. The power supply for the parts with the module varies, in some cases "transformerless".
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  • #4 21361541
    p.kaczmarek2
    Moderator Smart Home
    gulson wrote:
    I will post here an interesting comment from Facebook under the article:
    "A clue perhaps obvious, but explaining why the circuit may "not reset" when Vcc is unplugged. Namely, the high state on the Tx line of the converter flows through the input pin of the circuit to the power supply.

    Good point, I even discussed this in a separate topic:
    Microcontroller works without power supply connected? We are running on GND and UART alone, a conundrum.

    gulson wrote:
    Another non-obvious suggestion to readers, if such hardware is plugged into AC when programming or debugging - use a galvanic separator. One on USB is popular. And do not touch the side of the strip with your hand. The power supply for the parts with the module varies, in some cases "transformerless".
    .
    Also a good point, many Tuya products are "transformerless" powered (i.e. non-isolated step down inverter, I have not seen a "capacitor based" solution in IoT) although I personally just strongly discourage any tampering with mains connected hardware, it is in 99% of cases unnecessary to change the firmware. This can probably only be useful with the TuyaMCU to intercept communications analyser ,but fortunately there is also a solution to the same problem based on the developer site Tuya . In any case, modules from ADUM1201 can be used for galvanic isolation of the communication.
    Helpful post? Buy me a coffee.
  • #6 21361716
    p.kaczmarek2
    Moderator Smart Home
    I like the fact that this strip uses the CB3S module rather than the CB2S. There are more free pins. You could consider adding something in there, at least a sensor from the DHT series, such as the DHT11. Of course, this would have to be done sensibly, rather than inside the enclosure, but also safely, so that someone doesn't break off this sensor later and get shocked.... but it's a tempting prospect. You can get the DHT11 cheaply, especially if you set up a new account on Aliexpress:
    Set of 5/10 DHT11 sensor modules by Hornaxys available for $0.99. .
    Then you could also run the Charts driver in addition and make a chart:
    Charts in OpenBeken - configurable measurement history hosted on an IoT device .
    Helpful post? Buy me a coffee.
  • #7 21361822
    austin007
    Level 17  
    Interesting description. I used to drill such flat screws but the drill was on a tripod. With success. I don't know , why do they do this? EU regulations, does this give something to the manufacturer? Is it just about non-serviceability i.e. the EU version of the zero (customer) waste ideology?
    I once bought such a strip in Lidl only Zigbee and 3 controllable sockets. Very solid construction, filters, chokes, well designed and made PCB, good quality relays, copper wires with the right cross section. Very nice ABS housing. Prestige and quality for little money ;) .
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  • #8 21361967
    mtb1007
    Level 2  
    Thanks for all feedback!

    This is indeed the same device as https://www.elektroda.com/rtvforum/topic4080696.html#21264621. That post also mentions a nice way of opening the anti-tamper screws!

    p.kaczmarek2 wrote:
    Also a good point, many Tuya products are "transformerless" powered (i.e. non-isolated step down inverter, I have not seen a "capacitor based" solution in IoT) although I personally just strongly discourage any tampering with mains connected hardware, it is in 99% of cases unnecessary to change the firmware.


    The power section looks like a non-isolated switching power supply (step-down converter), so that's why I indeed mentioned to keep the mains lead unplugged all the time.
    Unfortunately, when all 4 channels are ON, the power strip heats up quite a bit, relays draw a lot more current than solid state switches.

    With PowerSave 1, all functionality remains ok, so that seems to be working fine. I'm not sure if I see effect in the CPU temperature reading, but maybe that's because I kept polling its web interface?

    Somebody asked me for a backup of the original firmware, I have attached it here.
  • #9 21372012
    erikwouterson
    Level 3  
    Hi All,

    Not sure if I need to post this as a new device ?

    Just finished modifying the LEDVANCE AC32646 and thought to post it in the Teardown section.
    To my surprise someone else did it to what looks like the same power strip without the USB connections, this device has 2 USB-A and 2 USB-C ports



    Interior of a modified LEDVANCE AC32646 power strip with visible circuits and wires.
    LEDVANCE power strip with USB ports
    LEDVANCE power strip with USB ports.

    Close-up of an internal circuit board with a communication module.

    I used BK7231GUIFlashTool-v5
    and OpenBK7231T_UA_1.17.821.bin



    Reg
    Erik

Topic summary

The discussion revolves around the teardown of the Action LSC Smart Power Strip (model 3202887 AL E24748 CB3S), which features four independently switchable sockets. Users share insights on modifying the device for compatibility with OpenBeken firmware, emphasizing the need for caution due to the direct connection of electronics to 230V mains without isolation. Various methods for opening the device's housing are discussed, including the challenges posed by flat-head screws. Users also mention the potential for adding sensors and the importance of using galvanic isolation during programming. The power strip's heating issues when all channels are active and the effectiveness of the PowerSave feature are noted. Comparisons are made with other similar devices, highlighting differences in construction and features.
Summary generated by the language model.
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