[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
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
Comments
Thank you for presentation. Btw, isn't the "4.???" pin CEN? Altough I am not sure... [Read more]
p.kaczmarek2 - Apologies about the late reply. My multimeter indicates that pin 4 is TXD2, not CEN. [Read more]
That's as I expected. Anyway... everything works correctly, right? If you need any help, just tell me. [Read more]
I've managed to use cloudcutter to pull one of these switches out of the cloud, and I have openbeken installed at the moment. What's strange is that via Home Assistant or the openbeken web interface... [Read more]
It means that software thinks that button is pressed by the user all the time. It may mean that you have chosen wrong GPIO for the button (one that has no button in reality) or that the Tuya is using inversed... [Read more]
Spot on, fixed. The issue was using btn_n incorrectly. No fixed and all is responsive. Thank you. [Read more]
Thanks for the fantastic write up. It worked perfectly for me! A couple of points of interest I found: - I am wondering why you opted to connect ground directly to the module instead of pin 5? I have... [Read more]
I am using power supply (turn off and on the power) trick all the time and it works very well. In some cases, while disconnecting the power from WiFi module, I sometimes have to temporarily connect... [Read more]