Sonoff 4CH (Pro*) use cases?


I haven’t really found much in my readings about what are typical use cases for the 4CH (Pro, etc).

Could I use a sonoff 4CH (Pro?) (R2?) to control the power to individual external harddrives?
(Yes I know you should just leave them running non-stop).

These harddrives (WD My-Clouds) are connected to my network, and are in a remote location. Crawling around to disconnect them is not fun.

I know I could connect each harddrive via a Sonoff Basic, so the real Qs are, 1. is it even possible to control 4 units and 2. does it provide some advantage to do so, (vs the Basics).

I’m hoping that using the 4CH Pro R2 (or other) would reduce the clutter of wires. But I don’t understand the “ratings” of the power for the 4CH units. I see there is separate power to run the board, and then 4 other sets. I don’t see how there is an “input” and and “output”, as you can see in the Basics.

Finally, there is the Q of how to deal with the physical power cords to the harddrives. Do I cut the existing HD powercords and splice them into the Sonoff (even the Basic) OR should I add some more clutter and only splice in separate extension cords for each?

Thanks for any ideas!

(P.S. I also posted this as a response to DrZZzs review of the 4CH, but as that video is old now, no ideas/opinions have been offered).


I don’t know.that I powering these drives up and down like that. Reason being is that they are not set up to write and ‘park’. In a normal computer config, the system will write to the drive and when idle, it parks the head. If there was any stray data not yet written… still sitting in memory… it is held until the next write cycle is commenced. I know the Cloud’s operate the same way since it is basically a simplified computer but i also know that they don’t completely flush the memory into the drive and park on.each write cycle. They do a limited cache for speed and efficiency and I made the mistake of unplugging mine shortly after accessing data on it and I lost some of that data. What I am getting at is that they don’t have a safe shutdown procedure that makes regular and random powerdowns a good idea.

As far as just killing.power, you could just as easily use a Basic and a power strip. If you are trying to get rid of the wall wart plugs for each of the drives then you need a power supply capable of powering all four under full rated load and again… you are only killing one supply source so you only need a Basic. With that said, you can buy (I am pretty certain) a power supply with an on off switch that could be rewired to be remotely operated either via extending the switch wiring or with a WiFi controlled device… like a Basic. (Grin) seeing the pattern?

I am sure there are use cases for the 4c. like running multiple lighting circuits and what not but I don’t believe your hard drive control solution is one of them. I haven’t personally found an application in my projects yet where I couldn’t replicate it easily using all low voltage components. But i am not doing anything (yet) that controls mains powered devices. Too much LV stuff to mess around with at this point.


One advantage the Sonoffs like the Dual and the 4 channel ones is that you are only using up a single IP address to connect the device to your network. Four Sonoff Basics would use up 4 IP addresses. The more devices you add to your wifi, the more congested it gets.


One use case I was considering very strongly about a year ago was using the 4C for my Smart Range Hood Project. The 4Ch would have a single Mains input, and four outputs from one device. The Range Hood conveniently uses four different mains powered things - 1 for the light, and 3 for the fan speeds - low, med, high. So this would have been a simple solution, and I would have added the DHT22 sensor.

That was the old plan, but I eventually went a totally different path and used a RaspberryPi and a separate relay board switched from the Pi.


The main use case for the Pro models is that they can be mounted on DIN rails, which is what you find in switchboards to mount all the circuit breakers. A row of Sonoff Pros can be clipped onto DIN rails to provide the (typically) dozens of outputs required in a whole-house home automation project. Then you only need to loop the supply side in once for every set of 4 outputs.

I currently have 34 switched circuits grouped together in one automation switchboard, and 18 in another. I’m not using Sonoffs for it (just DIN-rail mounted relays) but it’s the same principle. The Pros aren’t really intended for distributed end-point installation like the normal models, although they can be used that way.