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ATLO-TB2-TUYA - silent double light switch with WiFi control under Home Assistant

p.kaczmarek2  2 729 Cool? (+6)
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Interior of ATLO-TB2-TUYA touch switch with detached front panel beside .
Which silent light switch for the Home Assistant? Here is another product compatible with our Polish open source IoT software - ATLO-TB2-TUYA. This time without the relays. I will present here the double version, i.e. with two buttons, although you can get the same thing in a single or triple version. The price of the product is around £50 - depending on the number of buttons. You can get it cheaper by importing from China. This particular switch does not require a neutral wire to work. Let's start with the contents of the kit:
WiFi Wall Switch product box with graphic and smartphone on the lid Box of ATLO-TB2-TUYA light switch with printed configuration options .
Included is a capacitor, counteracts the glowing of the LEDs, also necessary for operation without neutral wire.
ATLO-TB2-TUYA switch set with capacitor and mounting screws Rear view of ATLO-TB2-TUYA WiFi light switch with labeled connectors .
We also get two screws for mounting to the box.
Installation and pairing instructions from Tuya:
Installation manual and wiring diagram for ATLO-TB2-TUYA switch Installation and pairing guide for ATLO-TB2-TUYA switch with Tuya Smart app. .

Let's get straight to the inside of the product. The front panel is removable.
Disassembled touch light switch with CB3S module and two-button front panel Interior of ATLO-TB2-TUYA double touch light switch with WiFi module
Designation: 3T86CBWIFIAV3.1
The whole is based on the CB3S module:
CB3S module mounted on control PCB in ATLO-TB2-TUYA wall switch .
Then we will change its software. Bottom view:
Bottom view diagram of CB3S module with labeled pins and exact dimensions .
That little chip on the board is not the TuyaMCU - it's a touch button controller.
Close-up of A1038 chip on green PCB with RX and CS labels around it .

Let's check the second board out of curiosity.
PCBs of disassembled ATLO-TB2-TUYA touch light switch lying separately .
You can immediately see that there are no relays here, so there will be no characteristic clicking.
Interior of the ATLO-TB2-TUYA dual touch switch with visible electronics .
The T1220H 800B is a triac with a current of up to 12A:
Excerpt from JIEJIE T1220H triac datasheet with specs and package diagrams .
Each of the triacs is separately controlled by a MOC3053 optotriac.
Triac control module with capacitor and MOC3053 on ATLO-TB2-TUYA PCB .
There is room on the board for a third pair:
Control board of ATLO-TB2-TUYA touch switch with visible components .
In addition there is a CSC7136B based power supply on the board.
Close-up of PCB with two capacitors and power IC labeled CSC7136B .
Some additional photos:
Close-up of ATLO-TB2-TUYA PCB with visible triacs and capacitors Close-up of PCB with capacitor, triac, and MOC3053 optotriac chip Close-up of PCB with capacitor, MOC3063 optotriac, and labeled components. Close-up of PCB with T1220H triacs and MOC3053 optotriacs .


Software change .
Just use our flasher:
https://github.com/openshwprojects/BK7231GUIFlashTool
All with instructions on the project page - you can also have a look at the related material on Youtube Elektroda.com (search under CB3S or better CB2S):
https://www.youtube.com/@elektrodacom
You need four cables - ground, 3.3V and RX and TX.
Close-up of CB3S module connected with four wires on ATLO-TB2-TUYA PCB .
The whole circuit (USB to UART converter with an additional 3.3V LDO on the contact board):
ATLO-TB2-TUYA switch board connected to breadboard and USB-UART adapter .
First we read the firmware. Flasher correctly discovers the configuration:
Screenshot of BK7231 GUI Flash Tool showing GPIO config extracted from CB3S module .
JSON Tuya:
Code: JSON
Log in, to see the code
.
Verbal description:

Device seems to be using CB3S module, which is BK7231N chip.
- Relay (channel 1) on P7
- Relay (channel 2) on P9
- WiFi LED on P6
- Button (channel 1) on P14
- Button (channel 2) on P24


OBK template:
Code: JSON
Log in, to see the code

Import template:


Import template.
Pairing with HA:


Import.

In summary , this product is distinguished by the absence of the characteristic click when switching. Just right for people who find it annoying or distracting, although someone else might say it's a downside because there is no 'beep' to tell you the circuit has been closed. Just whether such a 'signal' is needed? Rather, turning on a light is sufficient - as long as there is no problem with the bulb.
Changing the firmware was again very easy, there was no need to desolder the CB3S, and our flasher discovered the hardware configuration itself, so we didn't have to guess the GPIO.
The front panel of the device is also quite OK, with no disfiguring prints or unnecessary logos.
Is it worth it? This is your decision. In your opinion, is it worth reaching for such a "silent" version of the programmable light switch?

About Author
p.kaczmarek2
p.kaczmarek2 wrote 12894 posts with rating 10708 , helped 599 times. Been with us since 2014 year.

Comments

kris1966 21 Aug 2025 17:32

I have a similar one with relays. It even works but you have to focus on where your finger is touching. A normal bang with your paw, elbow, forehead and it worked and here it doesn't. I tried combining... [Read more]

p.kaczmarek2 21 Aug 2025 17:45

Which RF? This switch here does not have RF, although the forum has already shown WiFi+RF switches, such as those that pair with universal remotes. From what I remember, they have a receiver and the remotes... [Read more]

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