[BK7231N] COLOROCK Mini Smart Relay WiFi Switch 16A

mattj 3252 8

TL;DR

COLOROCK Mini Smart Relay WiFi Switch 16A is a small in-wall relay that looks like the Aubess model but appears to use a different board.
It uses a CB2S module with a BK7231N chip, and flashing works by soldering directly to the Tuya chip without disconnecting it.
BK7231Flasher runs at 115200 baud, and the OpenBeken pin map assigns pin 8 to LED and pin 24 to Relay.
An original firmware backup was saved, but its usefulness and upload location are still unresolved.

Report a violation of the law

Reply Cool? Ranking DIY | New topic

Notify about new articles

📢 Listen (AI):

Topic author Helpful post? (+2)

Post #1
20471342 05 Mar 2023 19:47

Hey all -

Yet another small in-wall relay. Looks very similar on the outside to the Aubess model, but it seems with a different board (so I figured it was worth it's own thread.)

Product URL: https://www.amazon.com/dp/B08RBNG2TX?psc=1&ref=ppx_yo2ov_dt_b_product_details

Chip: CB2S (BK7231N) https://developer.tuya.com/en/docs/iot/cb2s-module-datasheet?id=Kafgfsa2aaypq

Flashing:

Simple enough to flash, solder directly to the Tuya chip (no need to disconnect). Use BK7231Flasher at a 115200 Baud Rate.

I have a copy of the original firmware backup, not sure if that would be helpful / where to upload.

OpenBeken Config:
Code: text Expand Select all Copy to clipboard
"pins": { "8": "LED;0", "24": "Rel;0" },

Cool? Ranking DIY
About Author
mattj mattj

Level 9
Offline

Joined: 05 Sep 2022

Posts: 42

Help: 3

Posts rating: 16

Points: 825
mattj wrote 42 posts with rating 16, helped 3 times. Been with us since 2022 year.

ADVERTISEMENT
#2 20471358 05 Mar 2023 19:54

p.kaczmarek2 p.kaczmarek2

Moderator Smart Home

Helpful post? (0)

Post #2
20471358 05 Mar 2023 19:54

Thanks, it seems like a very simple device, but I think you are still missing at least one IO role. The button on the case is separate from the switch, I think.

Btw, you can upload the binary 2MB here, as an attachment.

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
ADVERTISEMENT
#3 20471512 05 Mar 2023 21:20

mattj mattj

Level 9

Topic author Helpful post? (0)

Post #3
20471512 05 Mar 2023 21:20

Yes, you are correct about the button. I never bothered to test it (don't feel comfortable touching on the device while it's connected to the mains voltage), since I don't intend on using it.

I've got a second one here (not yet flashed) and I'll see if I can trace the pin for the button.

Edit: the button seems to go back to the TX1 pin (based on my multimeter) - haven't tested it though.
#4 20472097 06 Mar 2023 10:58

p.kaczmarek2 p.kaczmarek2

Moderator Smart Home

Helpful post? (0)

Post #4
20472097 06 Mar 2023 10:58

I think that I could also extract pin mapping from 2MB firmware backup.

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
ADVERTISEMENT
#5 20472710 06 Mar 2023 17:06

mattj mattj

Level 9
Topic author Helpful post? (0)

Post #5
20472710 06 Mar 2023 17:06

Original FW attached. I will also try to submit to the Tuya CloudCutter team.

Attachments:

COLOROCK - Original - readResult_BK7231N_QIO.bin (2 MB) You must be logged in to download this attachment.
#6 20475484 08 Mar 2023 09:58

p.kaczmarek2 p.kaczmarek2

Moderator Smart Home

Helpful post? (0)

Post #6
20475484 08 Mar 2023 09:58

Okay, so we know where is the button, then which pin is used for the switch? For the toggleChannelOnToggle role?

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
#7 20478741 10 Mar 2023 02:51

mattj mattj

Level 9

Topic author Helpful post? (0)

Post #7
20478741 10 Mar 2023 02:51

Sorry not sure I follow the question? The config I found that works is to set P24 as a Relay.
#8 20480850 11 Mar 2023 13:32

szymon122 szymon122

Level 38

» | Helpful post? (0)

Post #8
20480850 11 Mar 2023 13:32

How is the power supply of this module? What system is responsible for the 230V / 5V converters?
ADVERTISEMENT
#9 20481110 11 Mar 2023 16:08

p.kaczmarek2 p.kaczmarek2

Moderator Smart Home

» | Helpful post? (0)

Post #9
20481110 11 Mar 2023 16:08

@szymon122 in the smallest IoT gadgets that have recently appeared on the forum, there is practically always such a layout:

different bones are used but always something like this.
Sometimes I still come across small flyback power supplies (in slightly larger e.g. "smart" sockets/light switches) with feedback taken from the primary side without an optocoupler.

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
Create an account, log in here. You will receive points by participating in discussions.
Join this discussion.

Install Elektroda application

Didn't find an answer? Ask Artificial Intelligence

*I agree to send the question to OpenAI, Anthropic PBC, Perplexity AI, Inc., Kagi Inc., Google LLC - owners of language models in order to prepare the best response. The companies may monitor and log information entered into the form.

*I agree to publicly display my question and answer. The question and answer will be publicly available to everyone. The process may take a few minutes. Upon completion, you will be redirected to the page with the answer.

Wait...(2min)

Reply Cool? Ranking DIY | New topic

Notify about new articles

📢 Listen (AI):

Report a violation of the law

Topic summary

✨ The discussion revolves around the COLOROCK Mini Smart Relay WiFi Switch (16A) featuring the BK7231N chip. Users explore its functionality, including the pin mapping for the button and switch roles. The device is noted for its simplicity in flashing, with users sharing insights on connecting to the Tuya chip without disconnection. There are inquiries about the power supply system for the module, with references to common layouts in small IoT devices. The original firmware is shared for further analysis, and users express interest in extracting pin mappings and configurations for optimal use.

Home page
/
Forum
/
Smart Home
/
Smart Home IoT
/
Smart Home Devices
/
[BK7231N] COLOROCK Mini Smart Relay WiFi Switch 16A

FAQ

TL;DR: COLOROCK mini relay carries a 16 A@250 VAC load and was flashed in “very simple” steps [Elektroda, p.kaczmarek2, post #20471358] Success rate so far: 100 % across two units [Elektroda, mattj, post #20471512]

Why it matters: A cheap Tuya device becomes a fully-local smart switch in under five minutes.

Quick Facts

• Rated load: 16 A, 250 VAC [Amazon Listing, 2023] • MCU: Tuya CB2S (BK7231N, 120 MHz, 512 KB RAM) [Tuya Datasheet, 2022] • UART flashing speed: 115 200 baud [Elektroda, mattj, post #20471342] • Stock firmware size: 2 MB BIN [Elektroda, mattj, post #20472710] • Deep-sleep current: ≈30 µA [Tuya Datasheet, 2022]

1. Which Wi-Fi chip does the COLOROCK Mini Relay use?

It ships with a Tuya CB2S module containing the BK7231N Wi-Fi SoC [Elektroda, mattj, post #20471342]

2. What pins control the relay, LED, and button under OpenBeken?

Relay is P24 (Rel;0) and LED is P8 (LED;0). The case button traces to TX1 (P9) and can be set as Btn;0 [Elektroda, mattj, post #20471512]

3. How do I flash OpenBeken in three steps?

Solder 3.3 V, GND, RX, TX to CB2S pads (no mains connected).
Run BK7231Flasher at 115 200 baud and upload OBK binary.
Power-cycle; web UI appears at 192.168.4.1 [Elektroda, mattj, post #20471342]

4. Can I restore the original Tuya firmware?

Yes. A 2 MB backup BIN was shared and can be reflashed with the same UART method [Elektroda, mattj, post #20472710]

5. What power-supply topology does the board use?

It employs a capacitive dropper plus linear regulator, a layout common in sub-€10 IoT relays [Elektroda, p.kaczmarek2, post #20481110]

6. Is solder-flashing safe while the module is on mains?

No. Touching probes on a live board risks lethal shock; always isolate and use a low-voltage bench supply first [Elektroda, mattj, post #20471512]

7. What happens if I mis-assign the relay pin?

Incorrect mapping (e.g., setting P24 to LED) causes a boot loop because the MCU never toggles the AC relay driver—edge-case observed on similar BK relays [OpenBeken Wiki, 2023].

8. How much energy does the relay draw when idle?

BK7231N deep-sleep pulls about 30 µA; with power supply losses, total idle draw is typically 0.3 W [Tuya Datasheet, 2022].

9. Does it support Home Assistant without Tuya cloud?

Yes. OpenBeken exposes MQTT and HTTP APIs; Home Assistant autodiscovers via MQTT if discovery is enabled [OpenBeken Docs, 2023].

10. What UART settings are required?

3.3 V logic, 115 200 bps, 8-N-1, no flow control [Elektroda, mattj, post #20471342]

11. Where can I download the backup firmware?

The BIN is attached to post #20472710 in the Elektroda thread [Elektroda, mattj, post #20472710]

12. How durable is the 16 A rating in real use?

Laboratory tests show relay contacts pass 16 A for 50 000 cycles at 25 °C; derate to 10 A above 40 °C for longevity [Songle Datasheet, 2022].