eWeLink-remote mini smart switch BL602

omelchuk890 17 Oct 2022 14:28 8 5709 Cool? (+6)

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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.

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

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p.kaczmarek2 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... [Read more]

omelchuk890 18 Oct 2022 17:40

@pkaczmarek2 aliexpress, shop O-OBEST listing Store Link I bought 5 pieces [Read more]

Steigan 24 Dec 2022 12:00

My configuration for this device: https://obrazki.elektroda.pl/5676860800_1671879568_thumb.jpg [Read more]

p.kaczmarek2 24 Dec 2022 12:03

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

Steigan 24 Dec 2022 12:09

Ok! Thanks! [Read more]

nomek 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. https://obrazki.elektroda.pl/1583841100_1673606742_thumb.jpg I bought it on Ali... [Read more]

hmonteiro 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... [Read more]

nomek 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. [Read more]

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].