Subj : Re: USB controlled mains switch
To   : R.Wieser
From : Chris Elvidge
Date : Sun Jan 19 2025 22:06:38

On 19/01/2025 at 19:24, R.Wieser wrote:
> Adrian,
>
>> ... the options seem to fall into two categories, either a relay device
>> which means having to rewire the device (which I'd rather avoid), priced
>> around 30Euros or one that sits in line (between the device and the
>> supply)
>
> Whut ?   As others have already mentioned, you could take a short extension
> cord and put the relais* in that cord.  Makes it reusable too.
>
> * also consider a solid-state relais.
>
> Also, you say USB controlled.  How do you imagine that ?  As some kind of
> special USB device (for which it is hard to find a driver) ?

As I have said previously, it's easy. E.g.
https://www.amazon.co.uk/Control-Intelligent-Channel-Controller-Support-default/dp/B07PWPF2DT
Load 'usbrelay' to control (apt-get install usbrelay')

>
> Perhaps consider a simple USB-to-serial thingly*, where you can use the DTR
> line to signal the relais board to switch on.  After that you can use the
> RPi build-in serial API to switch the relais.
>
> * I would strongly suggest to use one of RPi's gazillion I/O pins for it,
> but as you specifically mentioned USB controlled ...
>
> The only thing you will need to do (and which costs money) is to put the
> relais (and the USB-to-signal-line thingamagochy ?) in a shielding plastic
> box.  220 is lethal even when you touch it by accident. :-)   And make sure
> the 220v and the relais-driving low-voltage electronics are well seperated.
> Your RPi doesn't like 220v either. :-o
>
> Regards,
> Rudy Wieser
>
>



--
Chris Elvidge, England
I CANNOT ABSOLVE SINS

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