FAQ
TL;DR: 100 % local control in <5 min, prices from 30 PLN, “flashing over UART is trivial” [Elektroda, p.kaczmarek2, #21422555; #21425201]. Why it matters: Home-Assistant users can drop Tuya cloud, stop relay chatter, and keep RF remotes working—all with one open-source tool.
Quick Facts
• MCU: CB3S (BK7231N, 2 MB flash) in 72-087; T34-3 (BK7231T) or BL602 variants also appear [Elektroda, #21422555; #21427275].
• Street price: 30–60 PLN (≈ US $7–$14) per gang, shipped [Elektroda, #21422555; #21425161].
• Flash points: TX/RX, 3V3, GND, BOOT (IO0 on CB3S, IO8 on BL602) [Elektroda, #21422555; #21434649].
• OBK/OpenBeken supports >692 devices; templates live at devicesList.html [Elektroda, #21425201; #21427414].
• Edge case: tying IO8 high too long can brick BL602 modules [Elektroda, chemik_16, post #21440375]
Which chip does the Blow 72-087 single-gang switch use?
It carries a CB3S Wi-Fi module built around the BK7231N SoC with 2 MB flash [Elektroda, p.kaczmarek2, post #21422555]
How do I flash OpenBeken onto a CB3S-based switch?
- Solder 3 V3, GND, RX, TX and short BOOT (IO0) to GND.
- Connect a USB-UART at 115 200 bps and run BK7231GUIFlashTool; read backup first.
- Write the OBK binary, power-cycle, remove BOOT short, then pair in Home Assistant [Elektroda, 21422555]
What GPIO mapping should I use for 72-087 in OpenBeken?
Set P6 Rel;1, P20 Btn;1, P22 WifiLED_n;0, P26 LED;1 as per the OBK template supplied by the author [Elektroda, 21422555]
Can the switch run without a neutral wire?
Yes; the vendor ships a series capacitor to leak current, but LED bulbs may flicker for several minutes after power-up [Elektroda, chemik_16, post #21428051]
How can I auto-switch the relay off 20 s after pressing the touch button?
In the OBK console type:
addChangeHandler Channel1==1 addRepeatingEvent 20 1 setChannel 1 0
This creates a one-shot timer that resets the relay 20 seconds after activation [Elektroda, p.kaczmarek2, post #21502747]
Are there silent Wi-Fi touch switches with no relay clicking?
Look for models that use triac output; one example is the QTouch Wi-Fi switch dissected on Elektroda, which toggles without mechanical noise [Elektroda, p.kaczmarek2, post #21500938]
Why does my 4-gang panel stop sensing touch once mounted behind glass?
Metal wall boxes or the tempered-glass frame can detune the capacitive sensor. Add insulation tape or re-calibrate sensitivity via the touch-IC pad if available. Keeping a 1 mm air gap often restores detection [installer experience; capacitive sensor datasheets].
How do I enter bootloader and back up a BL602-based wall switch?
Momentarily pull IO8 to 3 V3 through a 10 kΩ resistor, reset power, then read the 0x0–0xFFFFF range with BouffaloLab DevCube at 2 Mbaud. Always release IO8 before normal boot [Elektroda, #21434649; #21434181].
What’s the risk if I tie IO8 directly to 3 V3?
Long contact can lock the BL602 in boot mode or corrupt flash; one user’s board stopped responding after such a test [Elektroda, chemik_16, post #21440375]
Will the 433 MHz RF remote still work after I flash Wi-Fi firmware?
Yes. The RF receiver is a separate SOIC-8 chip wired to the key controller, so replacing CB3S firmware leaves RF functionality intact [Elektroda, p.kaczmarek2, post #21427275]
How much do multi-gang versions cost on AliExpress?
Chemik_16 paid about US $7 for 4-gang and US $5 for 2-gang units when buying in bulk [Elektroda, 21425161]
Where do I find ready-made OpenBeken templates?
Do I need a resistor when pulling IO8 high on BL602?
A 10 kΩ resistor is recommended to limit current and avoid latch-up, as demonstrated in the YouTube guide shared by p.kaczmarek2 [Elektroda, 21434181]
What spec should I check to avoid relay noise?
Look for datasheets that specify SSR or triac output. If the listing mentions “no neutral” and includes a capacitor, it often uses a relay; ask the seller for triac model numbers like MQ-Txx series.
delicate these boufallo ;p
