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].