How to Fix Random Relay Switching on BL602 IoT Devices with SM-028_V1.3?
TL;DR
- Stop random relay switching on BL602L20-based SM-028_V1.3 switches by soldering the missing C6 0.1 uF and R1 10 kOhm components.
- Use the BL602L20/SM-028_V1.3 hardware details and flash OpenBL602_1.17.402.bin with blflash on COM7.
- Help DIY repairers and firmware modders because the relay can turn on and off randomly and make the smart switch unreliable.
- Wire the unsoldered module to a UART adapter with TX to RX, RX to TX, GND to GND, 3V3 to 3V, and BT to 3V before flashing.
Relay based on SM-028_V1.3 module with BL602L20 chip.
These relays have a massive problem with the fact that they randomly turn the relay on and off. In order to fix this, you need to solder components C6 0.1 uF and R1 10 kOhm.
For firmware, I unsoldered the SM-028_V1.3 module, connected the
SM-028|UART
TX--------RX
RX--------TX
GND-----GND
3V3------3V
BT--------3V module with the uart adapter, and then connected the uart adapter to the PC.
I flashed it using the blflash program with the command '.\blflash-windows-amd64.exe' flash OpenBL602_1.17.402.bin --port COM7.
Configuration:
{
"vendor": "eWelink",
"bDetailed": "0",
"name": "MINI Smart WI-FI switch",
"model": "WI-FI switch",
"chip": "BL602",
"board": "SM-028_V1.3",
"flags": "1024",
"keywords": [
"SM-028_V1.3",
"BL602L20"
],
"pins": {
"3": "TglChanOnTgl;1",
"14": "LED_n;1",
"20": "Btn;1",
"21": "Rel;1"
},
"command": "",
"image": "https://obrazki.elektroda.pl/9338489200_1705009676.jpg",
"wiki": "https://www.elektroda.com/rtvforum/viewtopic.php?p=20904492"
}
Comments
Good tutorial. It's a shame that manufacturer tries so hardly to optimize the costs that they don't actually even want to solder those two cheap components. [Read more]
After all, these components cost from $0.10 with assembly, I do not understand this savings. [Read more]
Maybe this should be corrected, as the sentence implies that these components should be removed, not added. [Read more]
By the way, I didn't even know that you can flash BL602 from the command line: .\blflash-windows-amd64.exe flash OpenBL602_1.17.402.bin --port COM7 I've always used BLDevCube.exe, and here's such... [Read more]
So I'm wondering if soldering these components corresponds to flashing in any way? Does soldering alone solve the relay switching problem in the original "ecosystem"? I have several switches under Tuya... [Read more]
But with the original firmware? Firmware can indeed affect the switch state detection to some extent. For instance, it is up to the firmware to determine whether the GPIO used has programmable pull-up... [Read more]
I don't think the ac is the problem. I need to take apart a switch that plays tricks on me sometimes. It's annoying insofar as it works as a pseudo-weather switch for the furnace. And it can turn itself... [Read more]
Look how much the parts are for on jlcpcb. A $0.10 would be 40 cents by now. With all the middlemen along the way it would probably make a buck. Well no two parts cost that much. [Read more]
By the way, this whole board is quite poor in components, even by Chinese standards. Only a fuse resistor protects the input, I don't see a varistor or anything else, and what's more, I don't see a second... [Read more]
Well, I don't know. These switches are rare and completely random in my opinion. It is difficult to talk about the influence of the algorithm here. On the other hand, an entry in the device log appears... [Read more]
0.1 mF or maybe 0.1 uF ? [Read more]
by supported commands - can read flash https://obrazki.elektroda.pl/2602001200_1705076546_thumb.jpg I couldn't flash it using BLDevCube.exe, it throws an error and I couldn't do anything about... [Read more]
this modification is not necessary by replacing the bl602 module with an esp 02s and installing tasmota. I tested it and it works great [Read more]
Just today I came across this thread (after last week's reprogramming of such a switch as in the thread) I took to testing with the swapped firmware on OBK. Unfortunately, I did not get a response to... [Read more]
@adinfo are you using the ToggleChannelOnToggle role here? Maybe it is indeed time to separate it into three versions (versions with pull up, with pull down and without pulls) and let users choose as required.... [Read more]
Yes, I am using ToggleChannelOnToggle - in this case the problem occurred, when I changed for testing, for example, to Btn then the problem with changing the state was not observed. As for the idea with... [Read more]
I also have BK7231N chip and its also chnage the state of S1 so it makes the relay on and off randomly. I removed the on board buttons but the issue is exist. I ll try to add a pull out resistor. [Read more]
https://obrazki.elektroda.pl/8061429500_1711040641_thumb.jpg I made this external pulled up with 4.7k with 104 cap for low pass filter. It works 100%. Pcb down side button removed. My casing has... [Read more]
. https://obrazki.elektroda.pl/8374053800_1740965908_thumb.jpg . Gentlemen, explain to me what gives this bridge that the circuit does not trigger itself? [Read more]