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Heruled Tuya WiFi Smart LED Controller - Lightning Semiconductor LN8825B chip

divadiow 7485 48
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  • #31 21243234
    divadiow
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    hot air yes. Maybe I'm being a little ambitious. I guess I'd need to sort aerial and oscillator as minimums. hmmm.

    I've just watched this https://www.youtube.com/watch?v=eSbZMZ7Y9IU
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    I'm looking through the datasheet and talking to ChatGPT about it.

    Added after 35 [minutes]:

    Actually, I might chicken out and look to just get some magnet wire to route all the test pads out to breadboard or rows of jumper headers. Use existing PCB and casing.
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  • #32 21262264
    divadiow
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    they're dinky little things. Will start with enamelled wire and case hacking approach first though.

    Microcontroller, wire coils, and a Sharpie marker on a table.
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    #33 21262268
    p.kaczmarek2
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    You will also need to add 100nF capacitors between VDD and GND pins for stable operation. At least one I guess. I'm not sure about other LN8825B pins, but often microcontrollers require a bit more components, like this 12k resistor for ESP8266:
    ESP8266 microcontroller connection diagram with capacitors and resistor.
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  • #34 21262290
    divadiow
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    thank you. maybe that kind of transplant is for another day. Oddly I've chosen 0.8 and 0.2mm wire, something in the middle might have been better. What selections of magnet wire do y'all keep?
  • #35 21262320
    p.kaczmarek2
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    You can still try, it's not that hard if you do clean soldering. I've did something similiar in the past, but not with QFN. Only TQFP at most. See:
    Universal starter boards for various SMD microcontrollers with a prototype area
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  • #36 21264697
    divadiow
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    A start. all 32 pins have continuity to outer header. No shorts. Seems I need to power 6 legs in total with 3.3v and, from what I understand, a 0.1 µF capacitor should be used for each.

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    PCB module with a QFN32 chip on a blue background. Five orange ceramic capacitors 0.1 µF on a blue electronics work mat.

    hoping I don't lose steam with it!

    Added after 8 [hours] 28 [minutes]:

    and yes, there is continuity between all 6 pads on the original PCB

    Close-up of a circuit board with a highlighted integrated circuit and solder connections. Pin layout diagram of an integrated circuit with highlighted power pins.

    Added after 1 [hours] 53 [minutes]:

    Diagram of LN8825B module with 32 pins labeled.
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  • #37 21265131
    p.kaczmarek2
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    Very good. Don't worry about placing all capacitors. From my experience, if there are multiple internally connected VDD pins, you can just use one 100nF capacitor for the start and it should work, more or less. For testing only, not for production. When I ran PIC32MZ on proto board, I didn't solder as many 100nF caps as there are VDDs.
    Of course, if there is some other pin that requires a capacitor, like, idk, "VDDCORE", and it's not connected to VDD, then you still need to solder that capacitor.
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  • #38 21265147
    divadiow
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    thank you!
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  • #40 21809115
    divadiow
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    divadiow wrote:
    Not sure what can be done with this, but I think this is a dump of the LN8825B Tuya LED controller firmware.


    I guess the backup wasn't too bad in the end. flashed back to OBDII LN8825B

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  • #42 21813802
    p.kaczmarek2
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    So, what's the generic state of this PR?
    https://github.com/openshwprojects/OpenBK7231T_App/pull/1946
    Tested, ready to merge?

    From my side, it looks more or less okay. It seems the LN882H was used for LN8825, so not many crucial changes there. Just like with W800 and W600.
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  • #43 21813819
    insmod
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    >>21813802
    Tested, and nothing broke on LN882H. Ready to merge.

    Is there any platform besides LN8825 that doesn't support float sprintf?
    If enabled on LN8825 (either wrap or via ldflags), it crashes as soon as wifi is on.
  • #44 21813833
    p.kaczmarek2
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    Perfect! Merged, anything else ready?

    I think we had some sprintf issue in the past, but it may have been related to the stack. We've tried some kind of lightweight sprintf replacement.
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  • #45 21813835
    insmod
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    >>21813833
    Flasher pr perhaps? I doubt i'll get anywhere further with KVs.

    First thing i tried is wrapping that nanoprintf function. Crash on wifi connect.
    At least when wrapping other 3 functions nothing broke. Thankfully, that is enough for something like printing internal temperature.
  • #47 21830464
    divadiow
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    @insmod @DeDaMrAz @p.kaczmarek2 how are you assessing whether or not ir commands received and shown by OBK are correct? by that I mean, I point the remote at Ir receiver and I see sometimes button presses are shown as for example NEC or EPSON or UNKNOWN, for the same button.

    How are you determining what the correct code really is? I don't have a flipper or whetever else can be used as stable base from which to assess OBK ir driver accuracy. I've not looked into whether there are any ESP32 apps I should be using, with well-developed and accurate timings configured, but even then I don't know if the irrecv and irsend Arduino-ish sensors I have are any good. I need a stable reliable baseline from which to judge whether or not OBK IR driver changes, when made, are working, worse, better etc

    The same for the sending, I want to know exactly WHAT/IF OBK is sending so I can see what the difference is, if anything, to what it should be.

    I have loads of Tuya T1, BK7231N ir devices, but of course they're running Tuya's app and they don't give enough visibility of their inner workings to see exact commands sent and received (I assume).
  • #48 21830940
    DeDaMrAz
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    divadiow wrote:
    The same for the sending, I want to know exactly WHAT/IF OBK is sending so I can see what the difference is, if anything, to what it should be.


    For this you will need something like a flipper zero.

    divadiow wrote:
    How are you determining what the correct code really is?


    Since we know OBK timing + IR is "flaky" my rule is which ever command is recognizable most times out of 10 tries. So if I get NEC "something" most of the time I go with that. It's not ideal but for what it's worth it's working for me.
  • #49 21831002
    divadiow
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    DeDaMrAz wrote:
    For this you will need something like a flipper zero.


    yep OK

    DeDaMrAz wrote:
    Since we know OBK timing + IR is "flaky" my rule is which ever command is recognizable most times out of 10 tries. So if I get NEC "something" most of the time I go with that. It's not ideal but for what it's worth it's working for me.


    yeh, that's kinda what I do too. I just thought I'd like something a little more objective.

    might not need to look too far to put something together that's kind of alright: https://github.com/crankyoldgit/IRremoteESP8266
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Topic summary

✨ The Heruled Tuya WiFi Smart LED Controller is based on the Lightning Semiconductor LN8825B chip, which is relatively undocumented and unsupported in common forums. Initial attempts to identify or flash the device failed due to lack of SDK and boot log access, possibly caused by reversed power polarity damaging the unit. Subsequent efforts revealed partial UART boot logs indicating a Tuya RTOS SDK dated 2020, suggesting similarity to the LN882x family, including the LN882H WiFi&BLE combo chip. Attempts to flash LN882H firmware onto LN8825B devices were unsuccessful, confirming incompatibility. Official LN8825B flashing tools and firmware dumps from Lightning Semiconductor FTP were found, with some RF test binaries booting and producing UART output, though no visible WiFi SSIDs appeared. Resources and firmware for LN8825B modules MOL100D0 and MOL100P0 were shared, including AT command firmware enabling UART interaction. Hardware transplant experiments involve desoldering the LN8825B QFN32 chip for prototyping, requiring a 40 MHz crystal oscillator and proper power supply decoupling with 100nF capacitors on multiple 3.3V power pins (VDD33, VDDA33, VIO1, VIO2). Pinouts differ from LN882H modules, complicating direct hardware swaps. Community members are exploring SDKs from Lightning Semiconductor's gitee repository and other sources, though some links are dead or restricted. Overall, the LN8825B chip remains challenging for custom firmware development and hardware hacking, but progress is ongoing with shared firmware dumps, flashing tools, and hardware reverse engineering.
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FAQ

TL;DR: With 2 confirmed UART modes and one key quote — "You have to pull A10 down" — this FAQ helps Tuya tinkerers identify, log, flash, and recover Heruled LED controllers built around the Lightning Semiconductor LN8825B, including why LN882H OpenBeken builds do not boot on it. [#21023961]

Why it matters: LN8825B controllers look similar to other Tuya Wi‑Fi boards, but the wrong flasher, wrong boot pin, or wrong firmware wastes hours and can soft-brick cheap LED hardware.

Topic LN8825B LN882H
Boot / flash entry noted in thread UART flashing works when A10 is pulled low Different flasher path used by community
OpenBeken result LN882H build does not boot on LN8825B Used as working base for existing support work
Evidence in boot strings ...sdk AT ln882x Also part of LN882x family
Tool compatibility Official LN8825B flasher works LN882H flasher fails on LN8825B

Key insight: LN8825B and LN882H are related enough to share the LN882x family name, but not enough to treat firmware, flash tools, or boot behavior as interchangeable. [#21029890]

Quick Facts

  • The readable LN8825B boot log exposes Tuya IOT SDK V:2.1.2, tuya light lib version 1.0.2, firmware string ln_rgb_zfbdpln1ynr6p3um:1.0.1, and build date 2020_09_10_14_41_46. [#20898850]
  • A restored factory image later showed both EZ mode and AP mode, with Wi‑Fi status changing from 1 to 2 and AP startup messages such as "Start Successful". [#21809115]
  • The LN8825B QFN32 transplant discussion identified 6 power-related pins to tie to 3.3 V: pins 3, 4, 11, 17, 29, and 30. [#21264697]
  • The chip transplant notes also call for a 40 MHz crystal oscillator and recommend 100 nF decoupling capacitors for stable bring-up during bench testing. [#21243234]
  • Known LN8825B-related module names in the thread include MOL100D0, MOL100P0, and SCW-T503; one module footprint matched TYWE3S/WB3S/CB3S for VDD/GND, but UART pin matching was only partial. [#21074899]

1. What is the Lightning Semiconductor LN8825B chip, and how does it differ from the LN882H in Tuya WiFi devices?

The LN8825B is a Lightning Semiconductor Wi‑Fi SoC used in Tuya LED controllers, and it is not drop-in equivalent to LN882H. "LN8825B is a Wi‑Fi SoC that runs Tuya firmware, belongs to the LN882x family, and exposes UART boot logs and flashing paths, but it uses different flashing behavior and firmware compatibility from LN882H in this thread." The thread shows LN882H OpenBeken images do not boot on LN8825B, even though both reference ln882x. [#21023961]

2. What does Heruled mean on this Tuya LED controller, and is it a brand name or a module name?

Heruled is the product brand name, not the module name. One reply states it appears as the brand in the AliExpress specifications table for the controller. That means Heruled identifies the finished LED device, while LN8825B identifies the Lightning Semiconductor chip on the PCB. [#20871841]

3. How can I capture a readable boot log from a Tuya LN8825B smart LED controller over RX0/TX0?

You can capture a readable boot log by powering the controller from its 12 V adapter and reading RX0/TX0 instead of relying on a weak external 3.3 V source. 1. Connect to RX0/TX0. 2. Power the board with the normal 12 V DC jack. 3. Cycle serial settings until the Tuya log becomes legible. The readable log later exposed Tuya SDK 2.1.2 and the ln882x build string. [#20871986]

4. Why does the LN8825B boot log look garbled at some baud rates, and how do I find the correct serial settings?

The log looks garbled when the serial settings are wrong or when the board is not powered cleanly. The thread showed mixed output with CH340 and PL adapters, and clean output appeared only after further testing with the normal DC supply. The practical method is simple: sweep baud rates, keep voltage stable, and stop when the repeated Tuya lines become readable instead of partly corrupted. [#20898850]

5. What can happen if I accidentally connect VCC and GND backwards on an LN8825B LED controller?

Reversing VCC and GND can kill the controller. One reply states reversed polarity is usually lethal for unprotected devices, and the original tester suspected that exact mistake after the board stopped behaving normally. On a cheap LN8825B LED controller, that can mean no app detection, no normal boot, and partial or permanent damage. [#20871841]

6. How do you put an LN8825B into UART flashing mode, and what role does pulling A10 low play?

You put LN8825B into UART flashing mode by pulling A10 low during flashing. 1. Connect the UART flasher. 2. Force A10 low. 3. Start the official LN8825B flashing tool. The tester first scratched a trace because no A10 pad was visible, then later found there was a test pad for A10 after all. [#21029890]

7. Why doesn’t OpenBeken for LN882H boot on an LN8825B, even when flashing appears successful in J-Link or the official flasher?

LN882H OpenBeken does not boot on LN8825B because successful flashing is not the same as binary compatibility. The thread reports J-Link showed a successful flash, and later UART flashing also worked, yet the LN882H OBK image still produced no OpenLN AP on LN8825B. That points to runtime incompatibility between the two chip variants, not a simple flashing failure. [#21023961]

8. Which flasher and SDK resources actually work for LN8825B, and why does the LN882H flasher fail on it?

The official LN8825B GUI flasher works, while the LN882H flasher does not. The thread also identified usable LN8825B resources such as Lightning Semi FTP dumps, an LN8825x flash tool, and later AT firmware from the M0L1_LN8825 package. By contrast, one direct test concluded that LN8825B cannot be flashed with the LN882H flasher. [#21029890]

9. LN8825B vs LN882H: which parts are compatible for firmware development, flashing, and OpenBeken porting?

They are partly compatible for research, but not interchangeable for production flashing. The shared ln882x family naming suggests similar SDK ancestry, and one maintainer later said LN882H support was reused for LN8825 with only limited changes. Even so, the thread repeatedly shows you must use LN8825B-specific flashing methods and validate firmware behavior on real hardware. [#21813802]

10. What does the boot log line "BUILD AT ... FOR ty_iot_wf_rtos_sdk AT ln882x" tell us about LN8825B firmware compatibility?

It tells you the firmware was built against a Tuya RTOS SDK targeting the broader LN882x family, not a single chip. The exact line shown was BUILD AT:2020_09_10_14_41_46 ... AT ln882x, which explains why people explored LN882H similarities. It does not prove full binary compatibility, because LN882H images still failed to boot on LN8825B. [#20898850]

11. How can I restore a dumped factory firmware backup to an LN8825B and verify that AP mode and RF are working afterward?

Restore the dump, then verify both UART behavior and radio activity. 1. Flash the saved factory image back to the LN8825B. 2. Watch the boot log for wf config AP mode and WIFI_MSG_ID_AP_READY. 3. Confirm RF activity from AP startup messages and higher PSU current during RF test firmware. In January 2026, a restored backup reached AP mode and logged successful AP start events. [#21809115]

12. What is the Tuya IOT SDK shown in the LN8825B boot output, and what can it reveal about the device firmware version and product key?

It is the Tuya runtime stack embedded in the controller firmware, and it reveals exact build metadata. The readable boot output shows TUYA IOT SDK V:2.1.2, product firmware ln_rgb_zfbdpln1ynr6p3um:1.0.1, and product key zfbdpln1ynr6p3um. Those strings help identify the device family, firmware age, and the Tuya product profile tied to the controller. [#20898850]

13. How do I test whether AT firmware on an LN8825B is actually responding, and what should I try if basic AT commands return nothing or -1?

Flash a known AT image, open UART, and test command formatting before assuming the firmware is dead. One tester flashed at_mylinks_uart_pro.bin from M0L1_LN8825 and then tried basic AT commands, first getting nothing and later -1 when auto-append was enabled. If plain AT fails, vary line endings, enable auto-append, and keep the same UART path that already produced boot logs. [#21068396]

14. Which LN8825B modules and footprints are known so far, and how close are they to TYWE3S, WB3S, CB3S, or ESP-12F pin compatibility?

The thread identifies MOL100D0, MOL100P0, SCW-T503, and the MQ-12F-related comparisons, but pin compatibility is only partial. One direct comparison says the LN8825B module matches TYWE3S, WB3S, and CB3S on VDD and GND footprint, while UART mapping does not fully line up. Another post compares LN882H MQ-12F to ESP-12F dimensions, not full pin-for-pin equivalence. [#21074899]

15. What’s the best way to validate OpenBeken IR receive and send accuracy on LN8825B when NEC, EPSON, and UNKNOWN codes appear for the same remote button?

Use an external reference device, because OpenBeken IR timing was described as flaky. One contributor said a Flipper Zero is the practical baseline for checking what is really sent or received. Without that, the working rule was statistical: press the same button about 10 times and treat the code recognized most often as the best current match. [#21830940]
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