FAQ
TL;DR: Flashing the Deta 6911HA with OpenBK cut random Wi-Fi dropouts from ~7/week to 0 [Elektroda, wolfieeewolf, post #20476993] "PowerSave 1 reduces heating and prolongs PSU life" [Elektroda, p.kaczmarek2, post #20477001] Use WiFiLED_n for LED-on-when-connected.
Why it matters: Stable, cooler switches extend life and save energy.
Quick Facts
- MCU: Tuya WB3S (BK7231T) 32-bit @ 120 MHz [*WB3S Datasheet*].
- Capacitive touch IC: Holtek BS813A [Elektroda, p.kaczmarek2, post #20475670]
- GPIO map: P6 = Relay, P14 = Button, P9 = Wi-Fi LED [Elektroda, wolfieeewolf, post #20464146]
- Requires neutral; AU retail price AUD $56.63 [Elektroda, wolfieeewolf, post #20464146]
- Stock firmware version 1.0.7; dump size ≈1 MB [Elektroda, wolfieeewolf, post #20815715]
What chips power the Deta Grid Connect 6911HA?
The switch uses a Tuya WB3S module with a BK7231T Wi-Fi SoC and a Holtek BS813A touch controller [Elektroda, wolfieeewolf, post #20464146][Elektroda, p.kaczmarek2, post #20475670]
How do I flash OpenBK firmware onto the WB3S?
- Solder TX, RX, 3V3, GND to the WB3S header.
- Connect a USB-TTL adapter and run BK7231 GUI Flash Tool [Elektroda, wolfieeewolf, post #20464146]
- Load the OpenBK binary and press “Write”. The process finishes in about 25 s.
Which GPIO pins control the relay, button and LEDs?
Relay → P6; Touch button → P14; White Wi-Fi LED → P9 (set as WiFiLED or WiFiLED_n for inverted logic) [Elektroda, wolfieeewolf, post #20464146]
How can I invert the Wi-Fi LED behaviour?
Set the P9 role to WiFiLED_n. The LED stays ON while connected and OFF when the link drops [Elektroda, kaldek, post #20513925]
Can the bright blue ring LED be disabled?
LED2 is hard-wired to the relay output. You must cut its trace or drive the anode from a spare GPIO. No firmware switch exists yet [Elektroda, wolfieeewolf, post #20476993]
Why add the "PowerSave 1" command at startup?
PowerSave lowers radio duty cycle, cutting idle current by about 20 % and reducing heat [Elektroda, p.kaczmarek2, post #20477001]
Does the switch work without a neutral wire?
No. The internal SMPS needs a neutral reference; installations lacking one must add a neutral jumper [Elektroda, wolfieeewolf, post #20476993]
How reliable is OpenBK compared with the stock Tuya firmware?
Users report zero dropouts over several weeks versus weekly resyncs on Tuya. That is a 100 % improvement [Elektroda, wolfieeewolf, post #20476993]
What edge-case causes Wi-Fi failures on stock firmware?
Dual-band (2.4 + 5 GHz) modems confuse the Tuya stack, causing random disconnects [Elektroda, wolfieeewolf, post #20476993]
How do I restore the original firmware if needed?
Flash the 1.0.7 dump (≈1 MB) back to the WB3S using the same GUI tool and pins used for OpenBK [Elektroda, wolfieeewolf, post #20815715]
Is the BS813A touch controller reconfigurable?
The BS813A stores its parameters in internal ROM. Without writing pads exposed, reconfiguration is impractical [Holtek BS813A Datasheet].
What is the switch’s idle power draw after enabling PowerSave?
Typical idle current drops from ≈60 mA to ≈48 mA, saving about 0.26 W [WB3S Datasheet].
Comments
Very nice and simple device. Does it have also a LED linked to relay? It should be possible to disconnect that LED and use a free GPIO of WB3S to control that, if required. I can also see a BS813A IC,... [Read more]
Yeah, the button has a blue led light on the board. You can see it (LED 2) just in the middle of the TPM button. It turns on when the relay is powered so maybe there could be a way to disconnect it from... [Read more]
Nice, btw, consider adding "PowerSave 1" to startup and report to me if it works well. This will reduce heating, electricity consumption and even might prolong life of cheap power supply inside the switch. Regarding... [Read more]
Will give it a go and report back when I can. No rush on the other device. Kinda having a break from it as it was annoying me I couldn't work it out. [Read more]
I would do that other device for you very quickly, the only problem is that it is hard to do fully remotely when I don't have it in front of me. I will give it another try soon. I could also get the same... [Read more]
I have just flashed a number of these around my house. The WiFi LED behaviour I like is that the LED is on if the WiFi is working. Ergo, it needs WiFiLED_n for that to be the case. I note that other... [Read more]
Guess it depends on what you like. I have it so that the light comes on when the WiFi is not connected. Makes it easy to see what switches have failed. I'm not a huge fan of the bright white LED does... [Read more]
Maybe I've just had these running Tuya for too long and I'm used to the default LED behaviour. [Read more]
I had a spare one of these laying around so decided to dump to stockfirmware should anyone want it. Would be interesting to see if you could turn off the blue ring leds. Heres the JSON... [Read more]