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[BK7231T] Globe Electric (GB34869) PAR20 WiFi Smart bulb - Discussion Topic

baudneo 2451 12

TL;DR

  • Globe Electric GB34869 PAR20 WiFi smart bulb discussion covers a newer revision using a BK7231N chip and an SM2135E RGW+TW LED driver.
  • Tuya Local control stopped working after a short time, with the bulb needing the mobile app and Bluetooth to wake up, so serial flashing became the path forward.
  • The board exposes Gnd, 20v, V+, 3.3V, CLK, and SDA, and the bulb runs firmware 1.5.21 with Tuya protocol 3.5.
  • Flashing succeeded without desoldering the daughter board, and GPIO detector JSON enabled switching and RGB color control, but brightness is low and white temperature turns the bulb off.
Summary generated by AI based on the discussion content.
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  • Hi, I am researching before I go cracking open 1 of my 6 bulbs.

    I had originally tried controlling these through HASS using Tuya Local library. The problem with these bulbs is that after a short duration of time, the bulbs go unresponsive and require using the mobile app and Bluetooth to 'wake' the bulbs up before they start accepting commands again. I can't implement a way to wake the bulbs using BLE and HASS while they are running their original firmware, so here I am.

    I've read up and watched several videos but, from the FCC internal photos, the daughter board is quite different than all the examples I have seen. I am just wondering if this type of board has already been flashed by any users here or if anyone can help me ascertain how to flash the chip.

    Here is a photo of the board:
    Close-up of a circuit board with BK7231TQN32 chip.

    and here is the FCC URL for the bulb.

    TIA!


    Added after 2 [hours] 2 [minutes]:

    Here are some more pics, this is apparently a newer revision as it uses the 7231N chip. I first tried tuya-cloudcutter but they don't have make/model or firmware version that this bulb has, the bulb has 1.5.21 firmware (tuya protocol 3.5). So, I am left with flashing via serial. The last picture is of the led board and has pinouts for the header on the PSU board.

    - Gnd
    - 20v
    - V+
    - 3.3V
    - CLK
    - SDA

    The 2nd last pic is the PSU PCB (to help ascertain what's what). I am wondering how I would connect this to my usb serial adapter?

    Thanks!

    Circuit board of a light bulb with visible electronic components.
    Close-up of a small electronic circuit board with visible traces and markings.
    Electronic board with a chip and quartz oscillator on a wooden background.


    Close-up of a circuit board with a chip and capacitor in a light bulb.

    Close-up of an LED bulb circuit board showing tracks and components.
    LED lighting module on a PCB with labeled connectors and electronic components.

    The board has it as an rgw+tw (sm2135e) and it has a 26000 crystal oscillator on the daughter board that is not present in the FCC internal pics.

    If there is anymore information I can give, plz let me know!

    Thanks!

    Added after 5 [hours] 5 [minutes]:

    So, I managed to get it flashed but now am tryign to figure out how to configure it properly. I did not need to desolder the daughter board but, it was good practice.

    I imported the JSON that the GPIO detector supplied adn I can toggle the light and change its RGB color. Its brightness is very low, the RGB colors need tuning and the white temperture slider turns the bulb off. I will comb through the docs to see if I can figure out how to get it working better.

    Happy that this project exists!

    Cool? Ranking DIY
    About Author
    baudneo
    Level 6  
    Offline 
    baudneo wrote 17 posts with rating 5, helped 1 times. Been with us since 2023 year.
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  • #2 20719800
    p.kaczmarek2
    Moderator Smart Home  
    Posts: 14699
    Help: 656
    Rate: 12743
    Thank you for the presentation, can you attach 2MB firmware dump or at least Tuya config partition?

    It looks like you need to adjust the RGB/CW current, maybe also enable SM2135 alternate mode flag. Search for SM2135_Current:
    https://github.com/openshwprojects/OpenBK7231T_App/blob/main/docs/commands.md
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  • #3 20720243
    baudneo
    Level 6  
    Posts: 17
    Help: 1
    Rate: 5
    I backedup the fw before i wrote to it but, the tuya-cloudcutter profile_builder.py script errors out when building a profile. I also have the .bin file from reading tuya config @ 0x1EE000.

    Tuya Cloudcutter profile builder error:
    Code: Bash
    Log in, to see the code


    There is a file folder with decrypted.bin and bootloader.bin even though the script failed.
    Code: Bash
    Log in, to see the code



    Firmware 2MB backup file: Globe-Elec...-RGBCT.bin (2 MB)You must be logged in to download this attachment.

    Tuya Config backup: BK7231N_Tu...F48BD8.bin (72 kB)You must be logged in to download this attachment.

    Here is the JSON from the writing process that I imported in the WebApp:
    Code: JSON
    Log in, to see the code



    I changed one of the sm2135 flags to send sepearate WW and CW and now the white temp slider works and the brightness is on par with stock tuya fw. After a second look of the bulbs beside stock tuya fw bulbs, the colors are correct. With the flags set, the bulb colors/temp/brightness are the same as stock tuya fw. Here are the flags I set: 5632.

    I will make another post of a full teardown and flashing as I have 5 more bulbs to do with the hopes of it being added to the product DB.

    Thanks for your work and effort, you have freed me from insidious tuya and their death grip on consumer IoT products.
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  • #4 20720472
    baudneo
    Level 6  
    Posts: 17
    Help: 1
    Rate: 5

    Well, this really really sucks. I flashed my 2nd/6 bulb and it all went well. Upon reassembly, it does not work. I used the "change OBK settings for flash write" and added my SSID/PW, MQTT broker info and then flags 9,10,12. The bulb never connects to the SSID and does not broadcast an AP. I went to go solder wires onto it again but, I lost RX1 pad so, I am unsure how I can flash it again......

    I probed the connector and there is 160VDC on V+, 3.3 on 3.3V. and Ground obviously is connected. I am not sure how I can test if the chip is getting power or not. I'm guessing this chip is toast. I am moving onto bulb 3/6. Soldering the TX and RX wires is a nightmare on this little board!
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  • Helpful post
    #5 20720482
    p.kaczmarek2
    Moderator Smart Home  
    Posts: 14699
    Help: 656
    Rate: 12743
    If you have made adjustments to the config, please also post the final template from the Web App, or at least make sure to include it in the final teardown. That's where all the settings and flags are.

    If your bulb does not connect to the WiFi, try doing 5 quick power off/on cycles to enable safe mode (AP mode) for OpenBeken and diagnose the problem.

    See our help:
    https://github.com/openshwprojects/OpenBK7231T_App/blob/main/docs/README.md
    And F.A.Q.:
    https://github.com/openshwprojects/OpenBK7231T_App/blob/main/docs/faq.md
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  • #6 20721160
    baudneo
    Level 6  
    Posts: 17
    Help: 1
    Rate: 5

    p.kaczmarek2 wrote:
    If you have made adjustments to the config, please also post the final template from the Web App, or at least make sure to include it in the final teardown. That's where all the settings and flags are.

    If your bulb does not connect to the WiFi, try doing 5 quick power off/on cycles to enable safe mode (AP mode) for OpenBeken and diagnose the problem.

    See our help:
    https://github.com/openshwprojects/OpenBK7231T_App/blob/main/docs/README.md
    And F.A.Q.:
    https://github.com/openshwprojects/OpenBK7231T_App/blob/main/docs/faq.md


    The 5 power off/on trick did it! I had a typo in SSID. I will create a new post with the teardown and pertinent settings.

    Thank you! I will be sending some support your way!
  • #7 20721187
    p.kaczmarek2
    Moderator Smart Home  
    Posts: 14699
    Help: 656
    Rate: 12743
    Thank you, all support funds go towards the development of new features, tutorials and devices. Just look at our list, we're heading towards 400 entries soon:
    https://openbekeniot.github.io/webapp/devicesList.html
    Many of them are my teardowns. Thanks to this, every smart device in my house is a different model :D

    Let me know if there is anything more I can do for you, I can implement features per request.
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  • #9 20721296
    p.kaczmarek2
    Moderator Smart Home  
    Posts: 14699
    Help: 656
    Rate: 12743
    I am usually adding device to teardowns list myself, but first I need JSON.

    The devices list database is here:
    https://github.com/OpenBekenIOT/webapp/blob/gh-pages/devices.json
    If you want to do the honors, open a pull request adding your JSON to the list.

    If not, I will add your JSON yourself, just make sure to post it.

    The JSON should consist device GPIO, generic tags and related keywords, forum image link and topic link.

    Please note that we have our own image hosting here at Elektroda, so there is no risk of your device expiring like the ImageShack images did, etc, etc.
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  • #10 20721429
    baudneo
    Level 6  
    Posts: 17
    Help: 1
    Rate: 5

    I have one last question, I think it is specific to MQTT light entity possibly or maybe I need to add an MQTT flag.

    In HASS, I have a helper group that contains 3 OBK lights. If I change the group to a color and then I turn the group off. When I turn the group back on, the color is set to warm white instead of whatever color they were before they were toggled off. Do you know of a way to have the bulbs in HASS remember their color or is that a HASS issue?

    Thanks!
  • #11 20722365
    p.kaczmarek2
    Moderator Smart Home  
    Posts: 14699
    Help: 656
    Rate: 12743
    What do you mean exactly by "turn off", do you mean disconnect power from the bulbs, so WiFi is also down, or do you mean just disable LEDs via OBK?

    I don't remember this issue. It should keep the color. You can try that by manually sending command:
    Code: text Expand Select all Copy to clipboard
    
cmnd/OBK_DEV_NAME/led_enableAll

    with payload 1 or 0.

    Or do you want to make OBK remember LED state between power sessions? There is a flag for that.
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  • #12 20723511
    baudneo
    Level 6  
    Posts: 17
    Help: 1
    Rate: 5
    Hi, by turn off I ment I toggled the bulb off using home assistant entity switch. I did set the power off remember state flag.
  • #13 20723523
    p.kaczmarek2
    Moderator Smart Home  
    Posts: 14699
    Help: 656
    Rate: 12743
    That's strange. Does manually sending just a simple led_enableAll 1 (or with 0) via MQTT also changes the colors?

    I am asking because HA might be sending some more data along with that.
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Topic summary

✨ The discussion revolves around the Globe Electric (GB34869) PAR20 WiFi Smart bulb, specifically issues related to its firmware and integration with Home Assistant (HASS) using the Tuya Local library. Users report that the bulbs become unresponsive after a short period, requiring a mobile app and Bluetooth to reactivate. One user attempts to flash the bulb's firmware but encounters errors with the Tuya Cloudcutter profile builder and issues with WiFi connectivity post-flashing. Solutions discussed include adjusting RGB/CW current settings, enabling specific flags, and using a power cycling method to enter safe mode. The conversation also touches on MQTT configurations for maintaining color settings in HASS after toggling the bulbs off. Ultimately, users share troubleshooting steps and resources for flashing and configuring the bulbs.
Summary generated by AI based on the discussion content.
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FAQ

TL;DR: For Home Assistant users converting Globe Electric GB34869 PAR20 bulbs, one user flashed 6 bulbs and reported "the 5 power off/on trick did it" after a Wi-Fi typo blocked recovery. Serial flashing worked without removing the daughter board, and SM2135 flag 5632 fixed white temperature and brightness on this RGBCW bulb. [#20721160]

Why it matters: This thread shows a repeatable path from unstable Tuya Local behavior to a working OpenBeken setup on a newer BK7231N-based Globe bulb.

Method Firmware / protocol fit What happened in this thread Best use here
tuya-cloudcutter Poor fit for firmware 1.5.21 / Tuya protocol 3.5 No matching profile; profile builder later failed with INVALID PAYLOAD and CRC-16 errors Good only if a supported profile exists
Serial flashing Worked on newer revision with BK7231N User flashed successfully and configured RGB after importing JSON Best choice for this bulb revision

Key insight: The decisive fix was not the flash itself but the post-flash configuration: enabling the right SM2135 behavior and saving the final OpenBeken JSON template made brightness, RGB, and white temperature match stock behavior. [#20720243]

Quick Facts

  • The exposed board header was labeled GND, 20V, V+, 3.3V, CLK, SDA, and the bulb used an SM2135E driver on an RGBCW layout. [#20719259]
  • The newer bulb revision used a BK7231N chip, had a 26.000 MHz crystal on the daughter board, and differed from the FCC internal photos. [#20719259]
  • The Tuya configuration partition was read at 0x1EE000, while the full firmware backup size requested in-thread was 2MB. [#20720243]
  • Stock firmware details captured from the bulb included firmware 1.5.21, Tuya protocol 3.5, and later JSON values showing dev_swv 1.3.21, brightmin 5, and brightmax 100. [#20719259]
  • During failure analysis after reassembly, the user measured about 160VDC on V+ and 3.3V on 3.3V, confirming hazardous mains-derived voltage is present inside the bulb. [#20720472]

How do I flash a Globe Electric GB34869 PAR20 smart bulb with a BK7231N or BK7231T chip over serial without removing the daughter board?

You can flash it over serial without removing the daughter board; the user later said desoldering was not required. Use the exposed PSU-to-LED board header, back up the firmware first, then write OpenBeken and import the detected JSON. The same thread later confirmed this newer revision used a BK7231N and was flashed successfully, with RGB control working immediately after the JSON import. [#20719259]

What are the correct UART wiring points on the GB34869 bulb when the exposed header is labeled GND, 20V, V+, 3.3V, CLK, and SDA?

The usable low-voltage reference points are GND and 3.3V; the other labeled pins include a dangerous 20V line and a measured V+ around 160VDC after reassembly. The thread does not provide a confirmed TX/RX pinout on that exposed header, only that the user soldered directly to tiny TX and RX pads on the daughter board and called it a nightmare. Treat CLK and SDA as signal lines, not proven UART pins, unless you verify them yourself. [#20720472]

Why do Globe Electric GB34869 bulbs become unresponsive in Home Assistant with Tuya Local until they are woken up with the mobile app over Bluetooth?

The thread reports that these bulbs stop accepting Tuya Local commands after a short time and only respond again after the mobile app wakes them over Bluetooth. No deeper root cause was proven in the discussion, but the practical problem was repeatable enough that the user abandoned stock firmware and moved to OpenBeken. In this case, replacing Tuya firmware removed the need for that BLE wake step inside Home Assistant. [#20719259]

What is the Tuya config partition at 0x1EE000, and how is it useful when converting a Tuya bulb to OpenBeken?

"Tuya config partition" is a non-volatile configuration area that stores device-specific settings, including module type, pin mappings, light mode, and version strings. In this bulb, the user dumped that partition from 0x1EE000 and extracted values such as module CBLC5, mode rgbcw, and SM2135-related I2C assignments. That data helps rebuild the right OpenBeken template when automatic tools or cloudcutter profiles fail. [#20720243]

How can I configure an SM2135E RGBCW bulb in OpenBeken so RGB colors, brightness, and white temperature work correctly?

Import the detected JSON first, then adjust SM2135 behavior until RGB and white channels map correctly. The user initially had dim output, correctable RGB, and a white-temperature slider that turned the bulb off. After changing one SM2135 flag to send separate WW and CW, brightness matched stock firmware and white temperature started working correctly. The same post says the final flag set used was 5632. [#20720243]

Which SM2135 flags or current settings should I adjust in OpenBeken when a flashed bulb is dim, white temperature turns the light off, or warm/cold white control is wrong?

Start with SM2135 current settings and, if needed, enable the alternate mode flag. The maintainer explicitly suggested adjusting RGB/CW current and searching for SM2135_Current, and also said the bulb might need the SM2135 alternate mode flag. In the successful follow-up, the user changed an SM2135 flag so WW and CW were sent separately and reported the final working flags were 5632. [#20720243]

Why would tuya-cloudcutter profile_builder.py fail with an INVALID PAYLOAD or CRC-16 error on a Globe Electric 34869 firmware dump?

It failed because the dump did not yield a valid app payload for the tool. The script reported "app - INVALID PAYLOAD", then switched to a scan pattern and stopped with "First block level CRC-16 checks failed" while analyzing the app partition. In this thread, that failure happened even though the bulb firmware had been backed up and the folder still contained extracted bootloader and decrypted files. [#20720243]

What is OpenBeken safe mode or AP mode, and how do 5 quick power cycles help recover a misconfigured bulb that will not join Wi-Fi?

OpenBeken safe mode is a recovery mode that brings the device up in AP mode so you can fix bad settings. 1. Power the bulb off and on quickly 5 times. 2. Wait for OpenBeken to enter safe mode and expose its AP. 3. Reconnect and correct the saved configuration, such as SSID or flags. In this thread, the exact method recovered a bulb that would not join Wi-Fi because the saved SSID had a typo. [#20721160]

How do I troubleshoot a BK7231 bulb that has 3.3V present after reassembly but no longer connects to Wi-Fi or exposes an AP?

First, force OpenBeken safe mode with 5 quick power cycles before assuming the chip is dead. The user saw 3.3V on the low-voltage rail and about 160VDC on V+, yet the bulb neither joined Wi-Fi nor exposed an AP. Recovery worked because the real fault was a mistyped SSID, not failed power delivery. If recovery does not work, then suspect damaged serial pads or board damage from rework. [#20721160]

What is the difference between flashing a Tuya bulb with tuya-cloudcutter and flashing it over serial, and which approach makes more sense for firmware 1.5.21 or protocol 3.5 devices?

tuya-cloudcutter depends on a matching supported profile, while serial flashing bypasses that requirement. In this thread, cloudcutter had no make, model, or firmware match for firmware 1.5.21 on Tuya protocol 3.5, and the profile builder later failed. Serial flashing then succeeded on the same newer board revision, making serial the practical choice here. For this specific GB34869 variant, serial was the method that actually worked. [#20719259]

How can I save and share the final OpenBeken JSON template for a Globe Electric GB34869 so it can be added to the device database?

Export the final Web App JSON after you finish GPIO, channel, and flag tuning, then post it or submit it to the device database. The maintainer said the device list entry needs the JSON, generic tags, related keywords, a forum image link, and the topic link. He also pointed to the database file and said a pull request is welcome, but posting the JSON in the thread is enough for manual addition. [#20721296]

Why might there be multiple hardware revisions of the same Globe Electric GB34869 bulb, and how can that affect flashing steps or GPIO templates?

This model appears in at least 3 versions, and newer hardware can differ from FCC photos and older guides. The user found a revision with BK7231N, an SM2135E RGBCW driver, and a 26.000 MHz crystal that was not present in the FCC internal images. That means UART access points, GPIO templates, and even flashing assumptions from v1 or v2 may not transfer cleanly to later boards. [#20721247]

How do I use MQTT commands like led_enableAll with OpenBeken lights to test whether Home Assistant is changing the bulb color state on turn-on?

Send the MQTT command directly to isolate Home Assistant from the bulb logic. The maintainer suggested publishing to cmnd/OBK_DEV_NAME/led_enableAll with payload 1 or 0 and then checking whether the bulb restores the previous color or shifts to warm white. If the direct MQTT toggle keeps color correctly, Home Assistant is likely sending extra state data when the helper group turns the light back on. [#20722365]

Why do OpenBeken bulbs in a Home Assistant helper group come back as warm white after being toggled off and on instead of restoring the previous color?

The thread does not confirm a firmware bug; it points first to Home Assistant sending extra data on turn-on. The user said a helper group containing 3 OBK lights returned to warm white after being toggled off and on, even with the remember-state flag set. The maintainer called that behavior strange and asked for a direct led_enableAll 1 test to see whether the color change came from HA rather than OpenBeken itself. [#20723523]

What is SM2135 alternate mode, and when should I enable it for RGBCW bulbs using the SM2135E driver?

"SM2135 alternate mode" is a driver option that changes how the SM2135E maps or drives RGB and white channels, especially on RGBCW bulbs with separate warm and cold white control. Enable it when a flashed bulb is dim, white temperature turns the lamp off, or WW/CW behavior is wrong. In this thread, the maintainer specifically suggested that flag for this bulb family before the user later fixed white handling with updated SM2135 flags. [#20719800]
Summary generated by AI based on the discussion content.
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