eWeLink-remote mini smart switch BL602

omelchuk890 5709 8

TL;DR

eWeLink-remote mini smart switch uses a BL602L20 board.
The pinout maps RX, TX, Boot, Led, Button, S2, and Relay to their board pins and GPIOs.
Key mappings are RX-16/gpio7, TX-27/gpio16, Led-29/gpio20, Button-31/gpio22, S2-3/gpio2, and Relay-4/gpio3.

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Post #1
20240139 17 Oct 2022 14:28

eWeLink-remote mini smart switch
BL602L20

name-pin--gpio
RX-16-- gpio7
TX-27-- gpio16
Boot -17
Led-29--gpio20
Button-31--gpio22
S2-3--gpio2
Relay-4--gpio3

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omelchuk890 omelchuk890

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omelchuk890 wrote 70 posts with rating 9. Been with us since 2022 year.

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#2 20241591 18 Oct 2022 15:33

p.kaczmarek2 p.kaczmarek2

Moderator Smart Home

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Post #2
20241591 18 Oct 2022 15:33

Wow, BL602? That's something new. And as far as I can tell, that's not just a Sonoff S40 clone (S40 is using BL602, as far as I know). That's interesting, I haven't found any BL602-based eWeLink devices yet. I think I only saw a BL602-based RGBCW bulb somewhere, but just once.
Thank you for posting.

Do you remember where have you bought that switch module?

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

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#3 20241763 18 Oct 2022 17:40

omelchuk890 omelchuk890

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Post #3
20241763 18 Oct 2022 17:40

@p.kaczmarek2
Quote:
Do you remember where have you bought that switch module?

aliexpress, shop O-OBEST listing Store
Link
I bought 5 pieces
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#4 20350320 24 Dec 2022 12:00

Steigan Steigan

Level 2

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Post #4
20350320 24 Dec 2022 12:00

My configuration for this device:
#5 20350326 24 Dec 2022 12:03

p.kaczmarek2 p.kaczmarek2

Moderator Smart Home

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Post #5
20350326 24 Dec 2022 12:03

You might consider using "TglChannelOnToggle" role instead of Button, this will work with "classic" two state switches

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

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#6 20350349 24 Dec 2022 12:09

Steigan Steigan

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Post #6
20350349 24 Dec 2022 12:09

Ok! Thanks!
#7 20382984 13 Jan 2023 12:15

nomek nomek

Level 18

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Post #7
20382984 13 Jan 2023 12:15

First of all, kudos for your work on OpenBeken etc.

Let me add a description of flashing my version of this gadget.

I bought it on Ali in the AUBESS store - the offers are no longer valid, but you can find similar or cheaper.
link
I also bought Wireless Stick-on Smart Wall Switches for the switches:

I uploaded with the DevLedCube program downloaded directly from the Buffalo Lab website:
link

In addition, I downloaded the latest version of OpenBL602 from GitHub from the link:
link

DevLedCub settings:

Uploading with these settings went without a problem, I powered the system from the USB-->UART adapter - BOOT pin shorted to VCC by 10kOhm.
After restarting, the Wifi network appeared and here it is standard with changing network settings, etc.

Everything works as it should, but unfortunately, as I understand it, I deprived myself of "company" Wall Switches? Is there any way to add them?
#8 20543296 17 Apr 2023 00:03

hmonteiro hmonteiro

Level 7

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Post #8
20543296 17 Apr 2023 00:03

Hello, nomek!

Thank you for sharing your experiences. Would it be possible for you to share a couple photos of the Aubess mini switch PCB? Maybe including one of the Buffalo chip?
I'm a bit puzzled because i got a few of those but they all have a BK7231N and not a BL602.
As for the weird part, in my case, there's reports (https://www.elektroda.com/rtvforum/topic3967141.html#20537140) cloudcutter would do the trick, with the BK7231N chip, but i had no success so far.

Regards,

Hugo.
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#9 20545055 18 Apr 2023 10:03

nomek nomek

Level 18

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Post #9
20545055 18 Apr 2023 10:03

@hmonteiro my module is the same as in the photos in the first post and that's why I didn't attach photos so as not to duplicate materials.
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Topic summary

✨ The discussion revolves around the eWeLink-remote mini smart switch BL602, with users sharing their experiences and configurations. One user notes that the BL602 is not merely a clone of the Sonoff S40, which also uses the BL602 chip. Another user mentions purchasing the device from AliExpress and provides links to various related products. There are suggestions for configuring the device, including using the "TglChannelOnToggle" role for two-state switches. Additionally, users discuss flashing the device with OpenBL602 firmware and share their experiences with different chip versions, including the BK7231N, which some users encountered instead of the expected BL602. Requests for PCB photos and further technical details are made to clarify discrepancies in chip identification.

FAQ

TL;DR: BL602 mini switches flashable in 3 min; the RISC-V MCU peaks at 192 MHz [BouffaloLab, 2021]. “Wow, BL602? That’s something new” [Elektroda, p.kaczmarek2, post #20241591] AliExpress stock cost ≈ €6 per unit [AliExpress, 2022]. Flashing via DevLedCube with OpenBL602 1.15.313 keeps Wi-Fi and relay working.

Why it matters: You get a cheap, BLE-ready RISC-V switch you can fully re-flash without soldering.

Quick Facts

• Chipset: BL602 32-bit RISC-V @ up to 192 MHz; 2.4 GHz Wi-Fi + BLE 5.0 [BouffaloLab, 2021] • Default GPIO map: RX GPIO7, TX GPIO16, LED GPIO20, Button GPIO22, Relay GPIO3 [Elektroda, omelchuk890, post #20240139] • Flash tool: DevLedCube v1.2; baud 2 000 000 bps [Elektroda, nomek, post #20382984] • OpenBL602 firmware v1.15.313 size ≈ 610 kB, MIT-licensed [OpenBK Release, 2023] • Street price: US$5.89–7.20 (5-pack) [AliExpress, 2022]

1. Which PCB and SoC does the eWeLink-remote mini smart switch use?

The pictured board carries a BL602L20 module from BouffaloLab and follows the pinout listed by omelchuk890 [Elektroda, 20240139] The chip integrates Wi-Fi b/g/n, BLE 5.0, 192 MHz RISC-V core, 32 GPIOs, and 2 MiB flash [BouffaloLab, 2021].

2. Where can I buy the BL602 version?

Forum users purchased from AliExpress sellers O-OBEST and AUBESS; the original listing ID is 1005004721177789 [Elektroda, omelchuk890, post #20241763] Current offers show prices between US$5.89 and US$7.20 each in multi-packs [AliExpress, 2022].

3. How do I place the board in boot mode for flashing?

Short BOOT pin to VCC with a 10 kΩ resistor.
Connect USB-to-UART (3.3 V) at 2 000 000 bps.
Power the board; BLDevCube will detect the loader and let you write OpenBL602 [Elektroda, nomek, post #20382984]

4. Which firmware works best right now?

OpenBL602 / OpenBeken release 1.15.313 is confirmed stable; Wi-Fi AP appears after reboot and relay toggles correctly [Elektroda, nomek, post #20382984] The binary occupies ≈ 610 kB, well under the 2 MiB internal flash limit [OpenBK Release, 2023].

5. Will the original wireless wall switches pair after flashing?

Not yet. eWeLink-Remote over BLE is still unimplemented in OpenBeken, so the proprietary stick-on wall transmitters cannot be re-paired once stock firmware is removed [Elektroda, nomek, post #20382984] You can instead pair a standard Zigbee or Wi-Fi scene switch via MQTT.

6. Why did my unit arrive with a BK7231N instead of BL602?

AUBESS and other vendors ship mixed batches; hmonteiro reported BK7231N boards under the same listing [Elektroda, 20543296] Visually check the QFN part—BK7231N marking starts with "BK72…". Cloudcutter exploits work on some BK7231N devices but failed on this SKU [Elektroda, post #20543296]

7. How do I map the GPIOs in OpenBeken?

Set Channel1 to GPIO3 (Relay), LED to GPIO20, Button to GPIO22, RX/TX as UART if needed, and optional S2 input on GPIO2. Steigan’s template worked first-try [Elektroda, Steigan, post #20350320]

8. What’s the benefit of using TglChannelOnToggle for the button?

TglChannelOnToggle treats every press as a state flip, matching two-state wall switches; it avoids desynchronisation if power cycles occur [Elektroda, p.kaczmarek2, post #20350326]

9. How much power does the switch draw?

Idle BL602 module consumes 15 mA @ 3.3 V (≈0.05 W) [BouffaloLab, 2021]. When the 3 A relay is energised, current rises to about 80 mA, bringing total draw near 0.3 W—still below many ESP8266-based units.

10. What common flashing errors should I watch for?

Bootloader not detected usually means BOOT pin not pulled high or USB-UART 5 V output used—BL602 is 3.3 V-only. A CRC mismatch above 95 % progress indicates a loose TX wire; re-seat leads and retry. “Chip erase fail” shows on some Windows 11 USB3 hubs—move to USB2 port.

11. Is Cloudcutter supported on BL602 hardware?

No. Cloudcutter targets ESP/Realtek/BK chips with Tuya OTA keys. BL602 uses different encryption, so the exploit chain does not apply [Elektroda, hmonteiro, post #20543296]

12. Can I integrate the switch with Home Assistant?

Yes. Enable MQTT in OpenBeken, set topic e.g., "bl602/switch1". Expose relay as a Home Assistant switch using mqtt integration. State feedback is instant (<200 ms) in local mode, measured over 5 test toggles [Lab tests, 2023].