INTL 3:770/1 3:770/3
REPLYADDR mjmahon@aol.com
REPLYTO 3:770/3.0 UUCP
MSGID:  a98397b9
REPLY:  7c626403
PID: SoupGate-Win32 v1.05
Mike Scott  wrote:
> On 10/02/2025 12:33, Joe wrote:
>> On Mon, 10 Feb 2025 09:12:32 +0000, Mike Scott
>>  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. But I see no
>>> indication of any way of resetting them to that known state without
>>> turning off the power - eg after reloading the pico control program.
>>>
>>> Has anyone used these and can offer advice please? Thanks.
>> I am using the HFD2/005-S-L2-D dual coil relays.  They work for my
purpose....
>>
>> See: https://source.hongfa.com//Api/DownloadPdf/323
>
> Thanks for the reply. I was considering complete units (like eg url
> below (*)), which differ in operation. They take a pulse on a single
> logic-level input, and flip-flop between states: my query is how to
> reset from a random state to the power-up state.
>
> The one you reference uses either reverse polarity or a 2nd coil to flip
> and flop.
>
>
>
> (*)
> 
>
> (No, I'd not pay that sort of price :-) )
>

In that case, the only reliable way to proceed is to provide a way to sense
the current state of the relay so that the desired state can be selected.

--
-michael - NadaNet 3.1 and AppleCrate II:  http://michaeljmahon.com

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