Subj : Re: latching relays
To   : David Higton
From : Joe
Date : Fri Feb 14 2025 10:09:33

On Mon, 10 Feb 2025 18:47:21 GMT, David Higton <dave@davehigton.me.uk> wrote:

>In message <vocfu0$14uka$1@dont-email.me>
>          Mike Scott <usenet.16@scottsonline.org.uk.invalid> wrote:
>
>> Hi all. I think a latching relay is the way to go for a pico-based job I
>> have in mind. However the prevalent ones all seem to be controlled by a
>> pulse on a single input wire which flips and flops the state.
>>
>> No doubt they reset to a known-state at power-up.
>
>It has always been my understanding that they retain their current state
>indefinitely, until the next pulse.  So there is no such thing as a
>reset state.
>
>David
Yes they remain their state BUT sometimes Arduino likes (from experience) & probably Raspi's give of spurious pulses on startup
which can be/needs to be prevented:

Known issue and solutions are on the internet i.e.
https://forum.arduino.cc/t/relay-turn-on-whenever-i-turn-on-arduino/644387

If the state needs to be knows between bootups, store the last setting in a file before/after switching and if needed send the
proper setting again after bootup.  That is why I like dual coil relays ;-)

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