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**Michael McSharry** · June 25, 2020, 06:24 PM

I have seen some YouTube video for digblur where he likes the Martin Jerry dimmers. I think there are also some dimmers that don't use the ESP8266. I have no info on the Gosund.

The only dimmers I have are the UPB ones, but seems there are different designs that affect usability. digblur did cover this subject but I don't remember what I saw.

**Pete** · June 25, 2020, 07:44 PM

Saw a take apart of a Gosund switch and the JTAG ports are clearly labeled and easy to get to. The purchase is only to experiment at this time as I have metal conduit and metal boxes for electric here.

Yes here house is using UPB for all of the in wall switches. In the last few years have reduced the footprint using multitoggle and dual load UPB switches.

**Guest** · June 26, 2020, 07:57 AM

Hi Pete probably this model I guess?

https://templates.blakadder.com/gosund_SW2.html

It uses Serial instead of Tuya for control and requires a small script for the capacitive touch panel.

I have have recently installed the Gosund switch KS-602S. installation was easy OTA and the unit works well. Hopefully the dimmer will work the same way. I think you have a preference for direct connection for flashing, I think its feasible as well.

Let us know how it goes,
Cheers

**Pete** · June 26, 2020, 08:07 AM

Thank you

Will do a take hardware apart pictorial here.

**Pete** · June 27, 2020, 07:25 PM

Got the Gosund dimmer switches today.

Guessing that Gosund doesn't want you to take apart the switch.

Smallest keyed torx screw I have ever seen. I did have a set here keyed torx drivers and have misplaced them so ordered a new set. Tried with a tiny screw drivers but had no luck as the screws were too tight. Guessing these are T3 size (.046 inch) (1.17mm)

I do not want to drill the screws out.

Stripped one screw using a screw driver. It will be be removed shortly.

**Pete** · June 28, 2020, 02:09 AM

Watched an interesting video on regular Gosund switch which will help me with this switch.

**Pete** · June 30, 2020, 07:17 AM

29th of June, 2020

Took apart the switch and noticed that it round pads labeled for RX, TX, GPIO0, 3.3VDC and RST and two ZIF style cables going from the push button board to the main board.

Will take a picture. Tried for a couple of hours to update the firmware. It did not work for me. This is the first time I have had this issue.

Went to doing it wirelessly OTA via Tuya Convert 2 and that worked for me. Powered it via USB connections while it was apart.

Did this on my linux laptop.

git clone hxxps://github.com/ct-Open-Source/tuya-convert
cd tuya-convert
./install_prereq.sh
./start_flash.sh

Wow totally different now than the old OTA application. Worked and it allows for a base Tasmota or Espurna firmware.

Initially installed the Espurna Generic Tuya Dimmer firmware. That did not work on the Gosund dimmer switch.

Went to Tasmota next. Wow looking good compared to the older Tasmota firmware. I am impressed.

Then read some more and found out I needed to remove one ZIF cable for the updating of firmware using the JTAG port.

Read some more and found that the Gosund dimmer switch is not the same as a Tuya dimmer switch over here ==> hxxps://templates.blakadder.com

The switch purchased is known as a Gosund SW2 dimmer.

All dimming and on/off functionality is controlled by an MCU that does not follow the Tuya protocol. Dimming and on/off can be set by Tasmota using simple serial commands. Reading local dimming when set by the capacitive touch panel requires a Script-enabled build and the script below to process serial status codes sent by the dimmer MCU.

So I installed the template and base 18 configuration.

{"NAME":"Gosund Dimmer","GPIO":[255,148,255,149,17,0,255,255,56,158,37,255,255],"FLAG":0,"BASE":18}

To use the script, you have to compile Tasmota with Scripting enabled.

Having issues with the Tasmota script bin installation found here ==> hxxps://github.com/tasmota/binaries as it was too big. Trying a zipped one instead.Upload buffer miscompare

The scripting Tasmota bin did not work. Getting the following error. Also tried a base Tasmota bin followed up by this one and it also did not work.

Upload buffer miscompare

It kind of works now. I can utilize the web gui to shut off and on and dim the switch. I have not installed it with a load but rather just some cables to power the switch.

Pressing the button I can turn it on and off. It doesn't appear to be dimming the switch when pressing the button and only the bottom LED lamp goes on and off. Only one dimming LED lamp illuminates.

I am very used to working with Espurna these days that relearning the Tasmota GUI now.

May test switch here and then later install it at families house. Just recently switched from the XFinity home system to the Ring Alarm system. Have two Amazon Echo Show's there that work nicely with the Ring Alarm. Will install these switches for the outdoor coach lamps there on the garage and front door.

Looking at the console see the following:

13:25:33 RSL: tele/tasmota_C28A11/STATE = {"Time":"2020-06-30T13:25:33","Uptime":"0T00:05:22","UptimeSec":322,"Heap":26 ,"SleepMode":"Dynamic","Sleep":50,"LoadAvg":19,"MqttCount ":0 ,"POWER":"OFF","Dimmer":27,"Fade":"OFF","Speed":1,"LedTab le" :"ON","Wifi":{"AP":1,"SSId":"ICS-ESPurna","BSSId":"E0:10:7F:XX:XX:XX","Channel":11,"RSSI":94, "Signal":-53,"LinkCount":1,"Downtime":"0T00:00:06"}}
13:27:39 RSL: stat/tasmota_C28A11/RESULT = {"POWER":"ON"}
13:27:39 RSL: stat/tasmota_C28A11/POWER = ON
13:27:44 RSL: stat/tasmota_C28A11/RESULT = {"POWER":"OFF"}
13:27:44 RSL: stat/tasmota_C28A11/POWER = OFF
13:28:18 RSL: stat/tasmota_C28A11/RESULT = {"POWER":"ON"}
13:28:18 RSL: stat/tasmota_C28A11/POWER = ON
13:28:21 RSL: stat/tasmota_C28A11/RESULT = {"POWER":"ON","Dimmer":84}
13:29:08 RSL: stat/tasmota_C28A11/RESULT = {"POWER":"ON","Dimmer":25}
13:29:10 RSL: stat/tasmota_C28A11/RESULT = {"POWER":"ON","Dimmer":26}
13:29:13 RSL: stat/tasmota_C28A11/RESULT = {"POWER":"ON","Dimmer":11}

**Guest** · June 30, 2020, 08:23 AM

Hi Pete,

you have to upload Tasmota-mimimal before uploading tasmota-script. Otherwise you exceed the onboard memory capacity.

hope this helps.

**Pete** · June 30, 2020, 08:45 AM

Thank you

Yeah tried a bunch of times :

1 - load Tasmota-minimal
2 - load Tasmota scripting bin
3 - same result each time: Upload buffer miscompare

Still though the manual push button on the switch only turns it on an off. It does though turn on at last dim level. Need to fix that part.

**Pete** · June 30, 2020, 11:45 AM

Wrote to digiblurDIY (Travis) about a bin file and script bin file and looked at some more of his documentation. Looks like I can upload the Tasmota script bin by JTAGing the device.

Just yesterday removed the wires from the pads and cleaned them up with a solder sucker.

**Pete** · July 2, 2020, 02:54 AM

02, July 2020 update

Was able to load the tasmota scripting bin initially loading the tasmota basic bin gz file then uploaded the script bin.

Adding the script and template found here ==> hxxps://templates.blakadder.com/gosund_SW2.html have the switch working fine now.

Code:

>D 100
rng=235
dimh=""
slider=0
power=0
dimval=1
a=""
b=""
c=""
d=0
f=0
;set the hex code below to the largest value possible that will turn off the relay with SerialSend5
off=0x7f

>B
dp0
rng-=off
=#scDim(dimval)

>E
slider=Dimmer
if chg[slider]>0
then
; dim according slider
if slider>0 and dimval!=slider
then
dimval=slider
=#scDim(dimval)
=>SerialSend5 %dimh%
endif
endif

if pwr[1]!=power
then
if pwr[1]==1
then
=>SerialSend5 %dimh%
power=1
else
=>Serialsend5 00
power=0
endif
endif

a=SerialReceived
if sl(a)>0
then
;process the first and second hex nibbles
b=sb(a -8 1)
c=sb(a -7 1)
a=""
;convert the first nibble to decimal – max value is 0x60
f=b
f*=16
;handle second nibble which may be 0x0-0xf
d=c
if d==0
then
switch c
case "A"
d=10
case "B"
d=11
case "C"
d=12
case "D"
d=13
case "E"
d=14
case "F"
d=15
ends
endif
;add first and second nibbles then to Tasmota dimming path
f+=d
=>dimmer %f%
slider=f
endif

#scDim(dimval)
dimh=hn((rng*dimval/100)+off)
=>print Scaled brightness is %dimh%

Using the scripting pieces allowed me to be able to manually dim the switch and see it dim in the console and use the GUI to dim and see the switch dimming leds illuminate.

08:50:06 MQT: stat/tasmota_C28A11/RESULT = {"POWER":"ON","Dimmer":50}
08:50:06 MQT: tele/tasmota_C28A11/RESULT = {"SerialReceived":"2403011C23240B011C232428011C23243C011C 232 446011C23244A011C23244C011C23"}
08:50:06 Scaled brightness is b5
08:50:06 Script: performs "SerialSend5 b5"
08:50:06 MQT: stat/tasmota_C28A11/RESULT = {"SerialSend":"Done"}

**Pete** · July 2, 2020, 12:04 PM

Took a couple of pictures of the second Gosund dimmer switch insides. Note to JTAG it you need to remove the top ZIF cable for the device to go in to programming mode.

Really now with the OTA programming you do not need to open / solder any type of temporary wires.

Noticing here that the 3.3VDC and Ground tabs have a cold solder look and there are no pads at the end of the ZIF cables like the first switch I took apart. Wondering if this was a return at one time. Will see how the programming works.

**Pete** · July 2, 2020, 06:14 PM

Update - 02nd of July, 2020

Updated 2nd Gosund Dimmer switch via powerline / OTA. Worked great first time.

Noticed now that the GZ files are included in the download repository. IE: as of yesterday.

Interesting when doing this today using Chrome Welsh language came up.

**Michael McSharry** · July 2, 2020, 07:11 PM

I agree the OTA for Tuya devices is very easy. Wonder how long the exploit will remain open.

Announcement

Gosund WiFi dimmer switches on sale on Amazon

Gosund WiFi dimmer switches on sale on Amazon

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