Sonoff T1 (UK) light switch with RF option


I recently discovered that my Sonoff T1 light switches which are all operated via an MQTT server have the ability to also be triggered by an RF signal. I have a Sonoff T1 for my bathroom light switch, and a Sonoff PIR sensor in the bathroom, connected to a Sonoff RF Bridge which automates the bathroom light when motion is detected. However, I ran into an issue recently where someone had leant on the switch for a number of seconds and inadvertently paired the RF functionality of the T1 to the PIR sensor in the bathroom. At this point I was not aware of the RF functionality so it took me some head scratching to work out why the bathroom light was going on and off like a disco!

But this got me thinking. The direct RF communication from the PIR sensor to the T1 is far quicker that routing the PIR trigger back to the RF bridge, processed by a rule and then publishing a message with MQTT, and would make a much better trigger when someone walks into the room. However, this functionality only seems to toggle on and off states. Does anyone know of a way to make the RF functionality of the Sonoff T1 only turn on the switch and not toggle states?

EDIT: I should probably add that the Sonoff T1 has been flashed with Tasmota!

A while ago now, I posted about a lag issue from the RF bridge which I never did solve and I am hoping that I might be onto something here… Fingers crossed.

One of us is confused.

I thought the Sonoff used 2.4GHz Wi=Fi which IS RF.

Apologies - I am talking specifically about the 433Mhz RF as used by the Sonoff PIR sensors and the RF Bridge etc.

The switches are also connected to my WiFi and work fine via MQTT.

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I don’t think so. The RF chips communicate with the esp8266 via serial. Tasmota knows the internal protocol used. By the way it’s a nice bit of reverse engineering.
There will be more details on the wiki. You can also ask their forum or ask @meingraham directly

Thanks vzorglub. I have been looking at the wiki but nothing that I have read there so far has suggested that it can be done, or for that matter that it cannot be done. I’ll reach out to there and see if they have any answers :wink:

The T1 has a relay which toggles the load (i.e., the light). It has a capacitive touch input which acts as a pushbutton. Finally, you can pair an external RF device (e.g., a PIR switch) which sends a code to the T1 which the T1 “sees” as a push on the button.

With this in mind, can you clarify your question? What do you want to accomplish (please refer to the relay, button, PRI, etc.)?


Hey Mike,

Thanks for your reply. I am specifically interested in the capability of the "external RF device (e.g., a PIR switch) as you put it.

In my example (scenario), I have a T1 operating a single light in my bathroom. I also have a RF PIR switch in the same bathroom. If I pair the PIR switch as an external RF device, I observe the following (undesired) behaviour. As the PIR switch detects first movement, the switch powers on the light, however a second motion detection from the PIR switch will turn the T1 back off again. A third back on, fourth off etc…

My desired behaviour would be the following:

When the PIR switch first detects motion the paired T1 turns on the light, but then, when the PIR switch detects motion for the 2nd, 3rd, 4th time etc., the T1 does not turn off again. For me the timer which is created in OH will take care of switching the light off after ‘n’ minutes.

The reason I am interested in this is that I have a small frustrating issue where currently there is some intermittent lag between the PIR switch detecting motion, sending this trigger to OH and then the light turning on which if “My desired behaviour” were possible, would solve for me.

I hope that has clarified what I would like to achieve. I fully appreciate that it may not be possible.


Then unpair it…


Thats exactly what I have done for now as it does not behave as I would like it. But, (and it’s a big but), if the behaviour of the the external RF device can be configured somehow to toggle or not toggle. I believe this would be a great feature for certain implementations of motion activated lights.

I don’t think so.
The microcontroller responsible for the RF decoding communincated with the ESP8266 in the T1 via the serial port. The internal protocol has been decoded and therefore we can still use the RF remotes with the T1 but I don’t think you can change the behaviour

Better ask in a Tasmota forum

I have my doubts also. but I’m keeping my fingers crossed. :slight_smile:

You can try using a Rule to control the behavior based on Button#State to only trigger to turn the light on. The difficulty is that if you want to turn it off manually using the capacitive button, this rule overrides that behavior. Thus, you can set a timer that will allow an “off action” after a certain amount of time. But I don’t think you can properly determine what amount of time is appropriate before allowing an “off” input without the PIR now triggering an “off” instead. So, I would let the PIR or button turn the relay ON but let OFF be handled by a timer. And, since the PIR will continue to trigger while it detects motion, it can be used to reset the OFF timer each time it detects someone preset. Finally, when the PIR has not detected motion and the timer expires (say 2-3 minutes after no motion), then the timer will trigger and turn the light off automatically.

If you have problems with the button, then use the T1 Template instead of the built-in Module and change the Button component to a Switch. This gives you some additional control by setting the SwitchMode that works best.


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