Any comments on the New Sonoff Basic R3

Hi Guys,
Any comments/reviews concerning the new Sonoff BasicR3 ? , Looks interesting and wondering if you still can flash the switch?


Hi Vaughanza,
Take a look at:
the video shows a “DIY tool” (warning - the music is shockingly bad)

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Just wanted to add some pics.
Just received 2 R3 Basic’s (non-RF) units.
Programmer at home.


Thanks guys appreciate it.

@Sawadee, thank you very much for posting your very detailed images here!

These are by far more useful for RE work than the other pics I found on github etc. Of particular importance, was the legibility of the relay markings, which allowed me to determine pinouts for a dry contact modification. Here is a link to an image of the relay I found by googling:

Unfortunately my google-fu turned up null as far as datasheets for this particular relay. However looking at the PCB bottom and using common sense (a diode across the coil pins, and it’s a 4-pin relay with the landing pattern gleaned from the pic above), we can guess which pins are the relay poles, and therefore exactly where the PCB needs to be cut to turn the R3 into a dry contact device. I made use of one of Sawadee’s images to illustrate my idea:

That cut on the left side is going to be trickier than on R1/R2 boards; there’s not much room between the relay pin and the resistor pad, and that resistor conenction must not be damaged. I’ve got my first set of R3’s coming in today (and S31’s too). So I’ll test this out and report back with the result. I’m 99% confident this will function as planned. I’m mainly interested in whether or not the cuts will significantly weaken the PCB physically. As such I will try to make the right side cut without going through the PCB entirely.

Any suggestions before I start are welcome!

[edit: On a side note, for those interested in powering an R3 off a 5V supply, there is also this simpler mod for dry contacts (doesn’t work if using 120V for power!):

Scroll down to DrFragle and MrShark’s comment from Dec 24, 2019.

Please do.


I do the cuts like in the images and its working. I do it with a scalpel