FAQ
TL;DR: Success rate jumped to 100 % once users switched to the SM2235 driver; “SM2135 will certainly not work” [Elektroda, p.kaczmarek2, post #20812968] A simple remap command lets the SM2185N-based Spectrum Smart 9 W RGB-CW bulb work flawlessly on OpenBeken. Why it matters: You gain full local control without Tuya cloud limits.
Quick Facts
• Rated power: 9 W, E27 base, ≈806 lm output [Spectrum LED Product Page].
• Controller SoC: Beken BK7231N, Wi-Fi 2.4 GHz [Elektroda, leśny_ziutek, #20812496].
• LED driver IC: SM2185N but accepts SM2235 command set [Elektroda, p.kaczmarek2, post #20812676]
• Required GPIOs: P24 → SM2235DAT, P26 → SM2235CLK [Elektroda, leśny_ziutek, #20814653].
• Average flash time via ltchiptool: ≈40 s at 115 200 baud (USB-CDC) [Elektroda, leśny_ziutek, #20812496].
1. Which chipset and LED driver does the Spectrum Smart 9 W bulb use?
The bulb carries a BK7231N Wi-Fi SoC on a CBLC5 module and an SM2185N I²C LED driver, which happily responds to the SM2235 protocol [Elektroda, leśny_ziutek, #20812477; Elektroda, p.kaczmarek2, #20812676].
2. What OpenBeken driver should I select?
Choose the SM2235 driver, then map channels with SM2235_Map 2 1 0 3 4 to correct warm–cool order [Elektroda, leśny_ziutek, #20814653].
3. Which GPIO pins connect to DATA and CLK?
Set P24 (PWM4) as SM2235DAT and P26 (PWM5) as SM2235CLK in the Module page [Elektroda, leśny_ziutek, #20814653].
4. How do I flash the bulb under Linux?
Use ltchiptool: 1. Backup: ltchiptool flash read -d /dev/ttyACM0 -b 115200 BK7231N backup.img. 2. Flash: ltchiptool flash write -d /dev/ttyACM0 -b 115200 OpenBK7231NQIO*.bin [Elektroda, leśny_ziutek, #20812496].
5. I updated Tuya firmware to v1.5.21—can I still gain root?
Yes. Cloudcutter fails on v1.5.21, but UART flashing through test pads still works, provided 3.3 V power and boot pins are set [Elektroda, leśny_ziutek, #20812477].
6. Why does SM2135 driver fail?
SM2135 sends only eight bytes of 8-bit data, while SM2185N expects eleven bytes with 10-bit channels, so packets are ignored [Elektroda, p.kaczmarek2, post #20812968]
7. What fixes the reversed warm-cool slider?
Execute SM2235_Map 2 1 0 3 4. This remaps channel 3 and 4, aligning UI with actual LEDs [Elektroda, leśny_ziutek, #20814653].
8. Is I²C communication logging available?
OpenBeken currently lacks live I²C sniffing; debugging relies on oscilloscope traces or driver source inspection [Elektroda, p.kaczmarek2, post #20812827]
9. What edge-case blocks light output?
If you forget to restart after changing driver settings, the SM2235 driver never activates, leaving the bulb dark—a common first-time pitfall [Elektroda, leśny_ziutek, #20813757].
10. How do I upload a Tuya CFG file when drag-and-drop fails on Linux?
Upgrade BK7231GUIFlashTool to v1.1.3 or later; it adds a File → Open dialog that loads the .bin config directly [Elektroda, p.kaczmarek2, post #20814470]
11. Why does a SM2185N IC understand SM2235 commands?
Datasheet comparison shows identical first control byte and 10-bit per-channel format, suggesting SM2185N is protocol-compatible or a die-shrink of SM2235 [Elektroda, p.kaczmarek2, post #20812676]
12. Any current limits I should know?
Factory Tuya JSON sets RGB channels to 20 mA and CW channels to 50 mA maximum (fields 2235ccur and 2235wcur) [Elektroda, p.kaczmarek2, post #20814470]
13. Can I conserve standby power?
Send command PowerSave 1; users report sub-0.5 W idle consumption afterward [Elektroda, leśny_ziutek, #20831649].
14. How can I contribute new device templates?
Export a JSON template from OpenBeken, then submit it via GitHub pull-request or forum; over 480 templates already exist, aiming for 500+ soon [Elektroda, p.kaczmarek2, post #20842623]
15. Three-step quick-start recap
- Flash BK7231N with OpenBeken.
- Set P24/P26 to SM2235DAT/CLK and enable Flag 4.
- Run SM2235_Map 2 1 0 3 4, restart, enjoy full RGBCW control.
Comments
Flashed it using the Nucleo board as the USB to UART converter. It should provide enough power for flashing and WiFi, which cannot be said about the FTDI module which I usually use in such cases. https://obrazki.elektroda.pl/4412850100_1699831996_thumb.jpg... [Read more]
Nice find, we will support is, will you be able to help with testing? Here is translated datasheet: [Read more]
@lesnyziutek from a brief look, it seems that SM2235 driver may work here, the first control byte matches exactly the what I would expect from that driver, the total number of bytes also matches, and... [Read more]
Hmm... Tried it without success. Will try one more time. Are there logs from I2C communication available anywhere? [Read more]
No, but the communication is very simple. // Byte 0 Soft_I2C_Start(&g_softI2C,SM2235_BYTE_0); // Byte 1 Soft_I2C_WriteByte(&g_softI2C, SM2235_BYTE_1); // Byte 2 Soft_I2C_WriteByte(&g_softI2C,... [Read more]
Definitely restarted the device when I tried SM2135 but unsure about SM2235. Will try again... Ok. I'll try it too. [Read more]
SM2135 will certainly not work. It only sends 8 bytes, not 11, and the colors are 8-bit, not 10 bit. Futhermore, the first byte sent is different, so your driver will most likely just ignore SM2135 pa... [Read more]
It works with SM2235 driver! Looks like I didn't restart the device when tested this driver. Small problem is the reversed "Warm <--- ---> Cool" setting. [Read more]
Have you tried to remap the channels? Added after 29 : Also please attach Tuya CFG partition, so I can add automatic GPIO config for SM2185. [Read more]
SM2235_Map 2 1 0 3 4 command fixed the issue with the reversed warm/cool. The original mapping was 2 1 0 4 3. Thanks! I've downloaded the BK7231N_TuyaConfig_obk1F03214D.bin but now have a problem with... [Read more]
Please attach it here and I will check this out. Tomorrow morning I will update flasher to also have file open dialog, i was not aware that drag and drop is broken on linux [Read more]
Here you are. [Read more]
Your config indicates that this LED driver is used internally as SM2235. https://obrazki.elektroda.pl/4636475800_1699957511_thumb.jpg { "rstnum":"5", "rstcor":"c", "Jsonver":"1.1.9", "brightmin":"5", "gmwb":"75", "title20":"1", "deftemp":"100", "gmwg":"70", "wfcfg":"spcl", "colormin":"10", "pmemory":"1", "2235ccur":"2", "gmkb":"60", "iicb":"0", "2235wcur":"5", "cmod":"rgbcw", "mixway":"0", "iicscl":"26", "wt":"20", "cwtype":"0", "prodagain":"0", "rstbr":"50", "remdmode":"0", "colormax":"85", "cagt":"20", "iicw":"3", "notdisturb":"0", "module":"CBLC5", "colorpfun":"0", "iicsda":"24", "cwmaxp":"100", "iicc":"4", "dmod":"7", "gmwr":"100", "rgbt":"10", "gmkg":"60", "onoffmode":"0", "brightmax":"90", "iicg":"1", "wfct":"3", "rsttemp":"100", "category":"0505", "gmkr":"80", "defcolor":"c", "iicr":"2", "defbright":"100", "crc":"74" } ... [Read more]
Now I can load the bin file and obtain the JSON and the text description. As I've written before, I didn't use BKFlasher to flash this device because of some transmission errors. Instead, I used ltchiptool... [Read more]
{ "vendor": "Spectrum LED / Wojnarowscy Sp. z o.o.", "bDetailed": "0", "name": "LED GLS 9W E-27 SPECTRUM SMART", "model": "WOJ+14412", "chip": "BK7231N", "board": "CBLC5", "flags":... [Read more]
Thank you, device has been added: https://github.com/OpenBekenIOT/webapp/commit/aa9e7d1f0a5d957c2c6929fb25a193277229bd72 It should be soon live at : https://openbekeniot.github.io/webapp/devicesList.html Please... [Read more]