part for latching relay or equivalent

I have a keyless entry number pad that has a timed NO output (either + or -, whichever is needed). It also has a NC output, which opens when the code is typed in (basically terminals 30, 87 and 87a of a SPDT relay, and the coil is operated by the keypad). I have reversing polarity door locks, so I need two outputs. I would like to build this-

I can't seem to find a single coil latching relay with a 12vdc coil, or anything that has pins similar to the one shown.

Does anyone have a good part number? Or can I do something else instead? Do I even need a latching relay considering what the keypad will do? I have a DEI 611t, but I don't think it will do what I want. Thanks.

hi,

you may want to look into a DEI 452T door lock pulse generator.  it will convert a latched input (such as a ground while armed) to door lock and unlock pulses.  you can use those outputs to drive relays to operate your door locks.

mark

Hmmm....

I don't think the 452T will do what I want either. It needs a constant input. Once the keypad de-energizes the coil, the output will open and the 452T will unlock the doors. The keypad itself isn't latching, its only momentary, and the timed output can only be set for a maximum of 99 secs.

Hmmm... now I'm a bit confused. I was under the impression that the diagram was good for what I wanted. I pulled it right from here- https://www.the12volt.com/relays/page5.asp. As far as I can tell, when the switch is pressed, the coil on the latcher is engergized, which will then in turn energize the coil on the large relay, sending ground to output 2. When the switch is released, both coils de-energize and no output is active. Now that the latcher is latched to the output, when the switch is pressed again, the latcher coil will energize, unlatching the output, and the big relay will output to output 1, since its coil isn't energized. When the switch is released, the latcher will de-energize and no output will be active.

Isn't that how a mechanical latching relay works? It maintains the last state it was in until the coil is energized again?  

This is the diagram for the part number you provided. As far as I can tell, pin 1 would get the switched ground, pins 6 and 7 would get 12v+, and pin 12 would connect to terminal 86. So you're saying the polarity between 1 and 6 would need to reverse to unlatch it? I guess my understanding of latching relays is less than what I thought....

dualsport wrote:

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These are single coil latching relays,
1 Form C, 2 Form C, and 4 Form C respectively:

DS1E-ML-DC12V DS2E-ML-DC12V DS4E-ML-DC12V

Available from Digikey: $5.44

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I was wondering, how can I find the same exact relays but in a more 'automotive oriented' packaging, I mean with a connector socket and all, not SPDT type ?

Any idea what to look for on the DigiKey site ?

dualsport wrote:

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Even with the correct relay though, the output may not be as clean as you might need, because it'll briefly send a short pulse on the other output before clicking over to the second output. If that's a problem, or you can't locate the relay, it'd be easier to do it with solid state components. A J-K flip flop along with a logic gate would do it.

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In that case, since I have even less clue about solid state stuff , and I just spent about 15 minutes Googling solid state flip flops with no idea what I'm looking at or for, do you have any good links to get what I need? Or maybe a diagram?

cahilj wrote:

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hi dualsport,

thanx for the reply.

yes,  i think 711 can be used.

my problem are:  it is not common here (allied does not ship internationally), cant find at ebay, and little overkill with DPDT

based on original schematic, i only need SPST.

if this is too hard to get, i'm thinking of electronic circuit for the solution.

how is your circuit above to be modified for this application?

regards

dualsport-

Thanks for all the help you've given. I'm going to give this a shot and see if I can package it to fit on the board I have.