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Sonoff Mini Not detecting physical switch


I've installed a sonoff mini and connected the signal wires to 3 3 way wall switches.

If I try to switch ON/OFF the sonoff using the app, there is no problem, it works like a charm always, but when I do it using the wall switches it just works "sometimes".

For what reasson can it be caused?

Is there any maximum length for the wires?

Should I activate any flag in the app?

5 people have this problem

Finally a possible solution. I arrived here with the help of a colleague from a Telegram group. I had already given up using the Sonoffs Mini due to this problem. At the time I had found nothing about it. In my case the problem happens when I use SMini on LED lamps that have a drive. In normal lamps, it works without problems. After the update to 3.5.0, the problem is different now. I had realized that the problem was also linked to the length of the cable. I will test the use of the capacitor and if it does not resolve, I will also test the use of the Cat5 cable, which Mello spoke.

I'm having similar issues. Have 4 sonoff mini's in the roof, all 4 powered in the roof space with 2 wires each (S1 and S2) coming down a conduit to a 2 separate light switches right next to each other.

All 4 Sonoff's have the same length wire, and same version of Tasmota running. 1 of the 4 switches is inconsistent with switching on and off.

Just got my 104 capacitors today, going to fit them this weekend. Will report back with findings.

I tested all my Mini Sonoffs with the 100 nF capacitor and the problem was solved. Thanks to everyone who contributed to the solution.

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Just finished installing the capacitor. It looks perfect now!!! No more ghost switching!!! I’m using the cat5 cable to connect the wall switchS from s1 and s2 and the capacitor between them Just to be clear, I’m on the original firmware...


I'm back after doing some tests.

For more information I have attached the installation diagram.

I'm still in trouble.



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@Fabio Yasuda, are you using a 474 k resistor?

resistor no, but a capacitor.

Just see the attached diagram that you will understand.


It’s the 104 capacitor... totally works for me... using an ethernet cabe... I’ll test the normal cable with the capacitor to see if it works too

This post was right on:==============================

For those who are using tasmota:

First of all, make sure that you are using the correct template in the Configure Template section. You can see it here:

Also, make sure that it is activated in the Configure Other

By default, the device will go to something like 'default' or 'user defined'. You set the template specified and it worked fine. My installation has 7 switches running down a long hallway. The circuit drives 3 LED fixtures on the ceiling. Initially, it worked from the Mini, but not from the switch. Changing the template fixed it immediately. Now, it picks up the switch flip from every switch without the use of a capacitor, and over the regular 14/2 and 14/3 copper used for the switches. I'd try this first. Go to the capacitor if this is all set and still doesn't work. Bear in mind, the switch doesn't react super fast, so quick on/off may get missed. So far, it's been a few days and I'm very happy.

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I have over 20 minis in my ceiling (no neutrals at the wall switch and could not run new cables) and had the ghost switching problem in a few of them. I followed the advice and took off the bottom half of the cases and soldered a 100nF electodeless capacitor onto the s1 and s2 inputs of all of them. They fit nicely and solved the problem except for 1 device. I tried moving the mini to the wall switch and using Cat 5 cable for the s1 and s2 connections with no luck. After weeks of searching online, I came across a simple solution that I should have checked in the first place. The wall switch was an old switch and changing it solved the problem. Just something to keep in mind if you have tried the 100nF capacitor solution and are still having problems. Try changing the wall switch as well.

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Just wanted to add that David’s comment about setting the template to activate was the fix for me, thanks for posting. Have been having this issue for months and this simple fix was the answer for me.

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