Single gadget, preferably USB, for switching on and off a mains socket from a Windows laptop

Question

My memory tells me that that Sinclair ZX81 could easily control a mains socket and therefore allow a user to do things like control the watering of pot plants without needing to get a soldering iron out or learn hacking skills.

Unfortunately, my memory seems to have been wrong, because I looked in the ZX81 manual and it contains nothing about this function. So I must be thinking of another very early model of home computer.

Anyway, what I need is a hardware device that I can plug into my Windows laptop, preferably into one of its USB sockets, and then wire a mains socket into it that the driver software for the device will be able to turn on and off.

I am aware of "smart plugs", but this is not what I am asking about.

Answer 1

This is partially an answer, as you've included "single" in your question and this is not a single item, but a full system.

X10 has been around since the last century, originally connected via serial port (DB-9!) to a bulky box of switches, which could be activated manually, of course. It's since evolved into something akin to today's technology.

X10 has a puck-like device to connect to a computer via USB. The non-single aspect of this system is that one is required to have one or more modules as the target for the software to control them.

image from linked site

This also provides for greater selection of the devices/modules you will be able to operate from the PC.