[BK7231T] Deta Grid Connect Smart Double Gang Touch Light Switch (6912HA)

This is a short teardown of the Deta Grid Connect Smart Double Gang Touch Light Switch (6912HA). It is sold in Australia and costs approximately $60 AUD from Bunnings.

The switch uses a BK7231T Tuya chip.

Pull off the faceplate and remove the cover by unscrewing the four screws shown. A tool is useful to pry away the cover.


Delicately pull out the PCB, being careful not to bend the contact bins in the lower left-hand side. A tool such as a knife is useful to do this.


Installing OpenBK7231T:

I inserted a 5-pin header terminal strip into the pin holes shown. From top to bottom (with the WB3S chip shown upright in the top right corner of the PCB) these correspond to:
1. 3.3V
2. TXD1
3. RXD1
4. TXD2
5. Ground

I connected 1-3 via female Dupont wires to the corresponding pins on an ESP flashing tool. I inserted a jig/harness on top of the WB3S chip that made direct contact with the ground pin as shown, and connected this also to a ground pin on the flashing tool. The harness is optional; I could also have just soldered it directly to the chip.



Lastly I connected a female Dupont wire to the RESET pin on the flashing tool and made contact with the WB3S CEN pin to trigger flashing mode during the flashing process.

Web App Configuration:
The chip started up fine with no issues. I configured WiFi and added the pin configuration below. This was adapted from Tasmota device information found here.

- P6: Relay 1
- P9: WiFiLed
- P14: Btn 1
- P24: Btn 2
- P26: Relay 2