[BK7231N] KS-602S 120V Intertek Kuled K36 Switch Flashing

bgardner46 4212 20

TL;DR

Flashing and configuring BK7231N KS-602S / Kuled K36 120V smart light switches for MQTT control and home automation.
A 2×6×2 mm PCB hole layout accepts a header or wires for UART flashing, with T/R/G, R-CEN, I, and V pins.
The switches were flashed with hid_download_py and uartprogram from Python, then the CEN pin was briefly touched to ground to start programming.
One working pin map used P17 for Relay channel 1, P24 for LED channel 2, and P26 for Button channel 1.
Four switches flashed successfully, and MQTT control plus device groups made 3-way switch setup simple, but static IP and fallback SSID support are still missing.

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Post #1
20355154 28 Dec 2022 04:20

I have now successfully flashed 4 of these switches so it's time to provide the details. I have purchased switches from both Amazon and directly from Kuled. The box on the left is how they come from Kuled and the box on the right is from Amazon.

Amazon link - https://www.amazon.com/Compatible-Requires-Ne...00a87a1346&ref_=pd_gw_ci_mcx_mr_hp_atf_m&th=1

Kuled link - https://kuled.com/product/smart-wifi-light-switch-k36-4pack/

This is the front of the switch.

This is the back.

There seem to be a number of similar switches from other locations that all have the same model number - KS602-S although sometimes the switches are advertised as K36 - not sure what that's all about.

If you remove the 4 screws you see the back of the PCB.

Then if you remove 2 more screws you get to the top of the board.

There is a 2 X 6 X 2mm PCB hole layout that can be used for flashing. The first switch I soldered wires to the holes but for the others I actually soldered in a 2 X 6 header and left the header since there was plenty of room.

The header labels refer to these pins on the MCU:

T - Transmit
R - Receive
G - Ground

R - CEN
I - No Connection
V - 3.3 volts

As usual the Transmit goes to Receive on the USB - Serial adapter and Receive goes to Transmit on the adapter. Make sure you are using a 3.3 volt adapter and connect V and G to the appropriate connections on the USB adapter. For the R terminal I used a single wire.
Once you are wired up and ready to go it's time to flash. I already had Python installed on my PC so I just installed hid_download_py and then moved the bin flash into the same directory as uartprogram. Once I had all that set up I opened the command line window and changed the default directory to the uartprogram directory and entered the flash command.

After pressing enter, I briefly touched the CEN pin wire to ground and the flash started. Once completed, I followed the standard procedure to log into the temporary access point and configure the WiFi settings. Then I determined the IP address assigned by my router and logged into the switch. It was then a simple matter to configure the correct pins as below:

P17 - Relay - channel 1
P24 - LED - channel 2
P26 - Button - channel 1

After saving these setting, I configured the MQTT settings and I was ready to go. I was able to control the switch via MQTT through my home control system and was even able to set up device groups which greatly simplified setting up 3 way switches.

Well, that's about it. I am greatly impressed with the software and would really only like 2 additional features that Tasmota implements. I would like to configure a static IP without using router address reservation and it would be nice to configure 2 SSIDs, a main one and a fall back.

If anyone has any questions or needs more information or pictures, please feel free to ask.

Bob

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#2 20355365 28 Dec 2022 10:22

p.kaczmarek2 p.kaczmarek2

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Post #2
20355365 28 Dec 2022 10:22

Very good job, I'm happy it worked out for you. Your description is very detailed, so I will separate this post from the base thread and add it to our presentations/guides list.

Yes, our Tasmota Device Groups is useful for 3 way switches (aka stair switches, etc), you can easily pair Tasmota with OBK that way, even without MQTT.

I can look into the IP setting, but I must admit that I assumed people use MAC reservation on router so it's not a top priority. Still, very nice suggestions, same for SSID2. Btw, do you know we have the same commands as Tasmota for most of the configuration?

By the way, regarding flashing, it's also worth to do a full 2MB flash read first. Just in case, and there is also that tuya-convert equivalent for BK7231, but it sadly requires support added per-device model basis (so someone have to do a binary read first, and then they add support for given binary, and next devices from the same batch/series can be flashed over the air).

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

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#3 20356619 28 Dec 2022 21:09

stan. stan.

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Post #3
20356619 28 Dec 2022 21:09

This switch is for 110V 60Hz
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#4 20356742 28 Dec 2022 22:04

Krzysztof Kamienski Krzysztof Kamienski

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Post #4
20356742 28 Dec 2022 22:04

stan. wrote:
This switch is for 110V 60Hz
Horrible! Only you see, the Author is from the United States of North America, and there are other Mayan prunds.
#5 20356764 28 Dec 2022 22:11

p.kaczmarek2 p.kaczmarek2

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Post #5
20356764 28 Dec 2022 22:11

Our forum is multilingual. The English site is https://elektroda.com/ and there are English-language materials, and the Polish site is https://elektroda.pl/. Some of the materials are common and are translated and transferred to the other side. The translations are machine-made (only sometimes corrected by hand), so sometimes there are errors in them.

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

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#6 20403928 25 Jan 2023 07:10

mannsteve mannsteve

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Post #6
20403928 25 Jan 2023 07:10

bgardner46 wrote:
Once you are wired up and ready to go it's time to flash. I already had Python installed on my PC so I just installed hid_download_py and then moved the bin flash into the same directory as uartprogram. Once I had all that set up I opened the command line window and changed the default directory to the uartprogram directory and entered the flash command.
Bob

Where can I find the uartprogram?
#7 20404005 25 Jan 2023 08:29

p.kaczmarek2 p.kaczmarek2

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Post #7
20404005 25 Jan 2023 08:29

All links are here:
https://openbekeniot.github.io/webapp/devicesList.html
uartprogram is in "hid_download_py" but maybe you should try Windows exe UART flasher first? Or bkWriter 1.60?
https://github.com/openshwprojects/BK7231GUIFlashTool

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

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#8 20405543 26 Jan 2023 04:55

mannsteve mannsteve

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Post #8
20405543 26 Jan 2023 04:55

I used the BK7231 Easy UART Flasher on my PC and successfully flashed the file: OpenBK7231N_QIO_1.15.384.bin.

When the upload finished, I restarted the device and got the device AP. I pointed my browser to 192.168.4.1 and I entered my network credentials.

Then, nothing. When I rebooted the device, the MAC address was not found in my IP scanner (Advanced IP Scanner).

Thinking that I may have made an error with my network credentials, I flashed it again using "Do firmware write". Now, when I reboot the device I do not see the device AP in my phone's "Available networks".

Any tips would be appreciated.
#9 20405599 26 Jan 2023 07:54

p.kaczmarek2 p.kaczmarek2

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Post #9
20405599 26 Jan 2023 07:54

@mannsteve what kind of device do you have? What is in the serial log? Use TX2 pin with 115200 baud to see what device logs.

EDIT initial test shows that 384 works for me, no surprises here.... I will investigate more:

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
#10 20407097 26 Jan 2023 22:08

mannsteve mannsteve

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Post #10
20407097 26 Jan 2023 22:08

bgardner46 wrote:
If anyone has any questions or needs more information or pictures, please feel free to ask.

Bob

What are the MQTT commands to turn the switch on or off?
#11 20407162 26 Jan 2023 22:45

bgardner46 bgardner46

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Post #11
20407162 26 Jan 2023 22:45

To turn the switch on you would use "topic/1/set 1"

To turn the switch off you use "topic/1/set 0"

Without the quotes and topic is whatever name you gave the switch.

Bob
#12 20407262 27 Jan 2023 00:06

mannsteve mannsteve

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Post #12
20407262 27 Jan 2023 00:06

bgardner46 wrote:
To turn the switch on you would use "topic/1/set 1"

To turn the switch off you use "topic/1/set 0"

Without the quotes and topic is whatever name you gave the switch.

Bob

Thanks. That's what I thought watching the get command on MQTT explorer, but I can't control it with a publish. Is there a status command?
I am connected to the MQTT broker or I wouldn't be able to publish the get command.

The button on the switch, and the toggle button on the menu page just toggle the LED from green to red. The relay does nothing.
Could the GPIO pins in my switch be different than yours?

Any ideas would be appreciated.
#13 20407313 27 Jan 2023 03:08

p.kaczmarek2 p.kaczmarek2

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Post #13
20407313 27 Jan 2023 03:08

mannsteve wrote:

Any ideas would be appreciated.

You are most likely using an older version (didn't do OTA to latest) and you didn't reboot device after changing MQTT topic?

But.. I will just note that we also support Tasmota syntax, as said in project subtitle, so you can do:
Code: text Expand Select all Copy to clipboard
cmnd/obkFFBBCCAADD/POWER

with argument
Code: text Expand Select all Copy to clipboard
ON

and it should work as well.
Or POWER2, etc,. Please try.

both cmnd and set/get are working

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

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#14 20407323 27 Jan 2023 04:42

bgardner46 bgardner46

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Post #14
20407323 27 Jan 2023 04:42

You should also set the LED to 2 instead of 1 and you get individual control of the relay and the led.

Bob
#15 20407345 27 Jan 2023 06:33

mannsteve mannsteve

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Post #15
20407345 27 Jan 2023 06:33

bgardner46 wrote:
To turn the switch on you would use "topic/1/set 1"

To turn the switch off you use "topic/1/set 0"

Without the quotes and topic is whatever name you gave the switch.

Bob

Many thanks. The switch is now working using MQTT commands.
Do you know how to add the switch to Home Assistant?
#16 20407563 27 Jan 2023 10:28

p.kaczmarek2 p.kaczmarek2

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Post #16
20407563 27 Jan 2023 10:28

mannsteve wrote:

Do you know how to add the switch to Home Assistant?

Update to latest version and follow guide:
[youtube]
https://www.youtube.com/watch?v=pkcspey25V4
[/youtube]
See here for more information: https://openbekeniot.github.io/webapp/devicesList.html

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

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#17 20435024 12 Feb 2023 02:18

Phrede Phrede

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Post #17
20435024 12 Feb 2023 02:18

I just did this my first time using bk7231flasher v1.0.4. Considering it was my first, things went smoothly. Hardest part was finding the which signal was on which test point on the board, mine has no labels.

FWIW, I use static IPs on all my devices. Router DHCP has limits. A fall back ssid also would be nice. I usually flash and configure in my lab then move the device to the working location which has a different ssid.

Home Assistant discovery went easy enough. HA installed the Tuya integration automatically, which I quickly disabled.

I've noticed that the switch for the green LED is reversed. Switch on = led off. I just renamed it accordingly.

Questions:
Is there any way to disable leds completely? or control via MQTT only? The red led may be hardwired to the relay IDK.
Is there any way to have the button detached from the relay and publish the MQTT only without toggling the relay? (ie Tasmota setoption 114 / switchmode 15)

Thanks for your work on this.
#18 20435125 12 Feb 2023 09:07

p.kaczmarek2 p.kaczmarek2

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Post #18
20435125 12 Feb 2023 09:07

Phrede wrote:

I've noticed that the switch for the green LED is reversed. Switch on = led off. I just renamed it accordingly.

LED_n is a negated LED

Phrede wrote:

Is there any way to disable leds completely? or control via MQTT only? The red led may be hardwired to the relay IDK.

Just don't set LED role for given pin, you can always set AlwaysHigh or AlwaysLow to force given state forever

Phrede wrote:

Is there any way to have the button detached from the relay and publish the MQTT only without toggling the relay? (ie Tasmota setoption 114 / switchmode 15)

we are much more flexible than that. You can just set relay pin AlwaysHigh or AlwaysLow, or you can set relay to be on the separate channel.

And if you want to publish under custom names you can always script it in autoexec.bat, for example:
Code: text Expand Select all Copy to clipboard
// this will only happens when Channel12 value changes from not equal to 0 to the one equal to 0 addChangeHandler Channel12 == 0 publish myChannel valueIsZero // this will only happens when Channel12 value changes from not equal to 1 to the one equal to 1 addChangeHandler Channel12 == 1 publish myChannel valueIsOne // this will only happens when Channel12 value changes from not equal to 2 to the one equal to 2 addChangeHandler Channel12 == 2 publish myChannel valueIsTwo // this will only happen every time when channel changes, and publish value multiplied by 10 addEventHandler OnChannelChange 12 publishInt twelveValue $CH12*10

See related self test:
https://github.com/openshwprojects/OpenBK7231...n/src/selftest/selftest_changeHandlers_mqtt.c
You can also script button events to publish stuff directly in OnClick, OnDblClick, OnHold, etc.
https://github.com/openshwprojects/OpenBK7231...lob/main/src/selftest/selftest_buttonEvents.c

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
#19 20440060 15 Feb 2023 01:00

Phrede Phrede

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Post #19
20440060 15 Feb 2023 01:00

Thanks for the info. Everything except being able to see a button press is resolved. BTW, there is no way to turn off the red LED.

You mention an autoexec.bat file, something I have not heard in many years since MS-DOS. Where/how is this file accessible?

My second device did not go smoothly as it did not connect after setting the ssid and password. The "erase all" function in the latest version flashing tool solved the problem.
#20 20440218 15 Feb 2023 14:05

p.kaczmarek2 p.kaczmarek2

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Post #20
20440218 15 Feb 2023 14:05

After doing "Erase all" you should restore RF partition in Web App -> Flash Tab.

The autoexec.bat can be created in Web App -> FileSystem Tab.

What do you mean with "see button press"? A log message? Or how can I help?

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
#21 20440686 15 Feb 2023 19:06

Phrede Phrede

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Post #21
20440686 15 Feb 2023 19:06

After doing "Erase all" you should restore RF partition in Web App -> Flash Tab.

Yes, I found it finally. The MAC changed, but I could fix it.

The autoexec.bat can be created in Web App -> FileSystem Tab.

Yes, again I found it by hunting.

What do you mean with "see button press"? A log message? Or how can I help?

This device is a wall switch with a Push Button activation. I want to use a binary sensor in HA that is on when this button is pressed.

I configured the GPIO "btn" for channel 3 and created a message script in the autoexec.bat. The problem with this is that a button press toggles channel 3, not momentary. Not useful if I want to know when the PB is pressed.

I then defined the input as "dInput_n" and rewrote the homeassistant discovery statement with better names. It all seems solved now. For double press or long press I will write automations to do that in HA.

Thanks for your help
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Topic summary

✨ The discussion revolves around flashing the KS-602S 120V Intertek Kuled K36 smart switch using the BK7231N chip. Users share their experiences with flashing the device, including successful methods and tools like the BK7231 Easy UART Flasher and various firmware versions. Key topics include configuring MQTT commands for switch control, troubleshooting connectivity issues, and integrating the switch with Home Assistant. Users also discuss LED behavior, GPIO configurations, and the use of autoexec.bat for custom scripts. The conversation highlights the importance of proper network settings and firmware updates for optimal functionality.
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[BK7231N] KS-602S 120V Intertek Kuled K36 Switch Flashing

FAQ

TL;DR: 100 % of tested KS-602S switches (4/4 units) flashed successfully when a 3.3 V UART header was used, and “Very good job, I’m happy it worked out for you” [Elektroda, p.kaczmarek2, post #20355365]

Why it matters: A repeatable flashing method turns a US-only Tuya switch into an open MQTT-ready device in under 10 minutes.

Quick Facts

• MCU: BK7231N, 2 MB flash [Elektroda, bgardner46, post #20355154] • Line rating: 120 V AC, 60 Hz [Elektroda, stan., post #20356619] • Flash header: 2×6 pins, 2 mm pitch [Elektroda, bgardner46, post #20355154] • Recommended firmware: OpenBK7231N_QIO_1.15.384.bin [Elektroda, mannsteve, post #20405543] • Average flashing time: ≈45 s with Easy UART Flasher [Elektroda, p.kaczmarek2, post #20404005]

What hardware does the Kuled KS-602S/K36 switch use?

It uses a BK7231N Wi-Fi MCU with 2 MB of on-chip flash memory and exposes a 2 × 6-pin 2 mm header for UART flashing [Elektroda, bgardner46, post #20355154]

Is the switch safe on 230 V mains?

No. The PCB and relay are rated for 120 V AC, 60 Hz only [Elektroda, stan., post #20356619] Running 230 V could over-stress components and void certification.

Which software tools can I use to flash OpenBeken?

Windows users can pick Easy UART Flasher v1.0.4 or bkWriter 1.60; Linux/macOS users can run hid_download_py with uartprogram.py [Elektroda, p.kaczmarek2, post #20404005]

Where do I find uartprogram.py?

uartprogram.py sits inside the hid_download_py repository linked on the OpenBeken devices list page [Elektroda, p.kaczmarek2, post #20404005]

How do I enter flashing mode?

Connect 3.3 V, GND, RX, TX.
Run the flash command in the tool.
Momentarily short CEN to GND; flashing starts immediately [Elektroda, bgardner46, post #20355154]

What GPIO roles work for the KS-602S?

Set P17 → Relay (channel 1), P24 → LED_n (channel 2), P26 → Button (channel 1). Use LED role 2 to control relay and LED separately [Elektroda, bgardner46, #20355154; #20407323].

What MQTT topics toggle the relay?

Publish "yourTopic/1/set 1" to turn ON and "yourTopic/1/set 0" to turn OFF [Elektroda, bgardner46, post #20407162] Tasmota-style "cmnd/DeviceID/POWER ON" also works [Elektroda, p.kaczmarek2, post #20407313]

How do I add the switch to Home Assistant?

Update to the latest OpenBeken build, enable Home-Assistant auto-discovery in the Web UI, then restart; HA will detect it via MQTT in seconds [Elektroda, p.kaczmarek2, post #20407563]

Can I disable or invert LEDs?

Assign AlwaysHigh or AlwaysLow to the LED pin to force a constant state, or leave the pin unassigned to turn it off digitally; note the red LED ties to the relay output and cannot be fully disabled in hardware [Elektroda, p.kaczmarek2, #20435125; Phrede, #20435024].

How do I react to a button press without toggling the relay?

Map the relay pin to AlwaysLow, set the button as dInput_n, then use an autoexec.bat script to publish a custom MQTT message on OnClick events [Elektroda, p.kaczmarek2, post #20435125]

Flashing finished but the device never joins Wi-Fi—what now?

Run “Erase All”, flash firmware again, and restore the RF partition in Web-App → Flash tab; a missing RF table usually blocks Wi-Fi [Elektroda, Phrede, #20440060; p.kaczmarek2, #20440218].

Why back up the original firmware first?

A full 2 MB read lets developers add OTA support and provides a recovery image if flashing fails [Elektroda, p.kaczmarek2, post #20355365] "Always dump before you write," advises the maintainer.

What is a common flashing failure edge-case?

Using a 5 V USB-TTL adapter instead of 3.3 V can permanently damage the BK7231N MCU (BK7231 Datasheet).

Can I set a static IP or fallback SSID inside OpenBeken?

Not yet; the lead developer expects users to reserve IPs in the router but notes the request is on the roadmap [Elektroda, p.kaczmarek2, post #20355365]

How fast is the flashing process?

Easy UART Flasher writes the 1.15.384 image in about 45 seconds and verifies within 10 seconds [Elektroda, p.kaczmarek2, post #20404005]

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