Any latching relay drivers you'd care to recommend?

[Mark Hammer]

I have a couple of OMRON G5AK-237P 5V latching relays - like these: https://i.ebayimg.com/images/g/95MAAOSwpsBckj5z/s-l400.jpg - that I'd like to employ as loop selectors, using a momentary switch.

I have just discovered the wonders of relays this past week.  Can anyone point me to a circuit that actuates such a device appropriately?  The coils in each relay are spec'd at around 125R each.  I gather the actuating simply has to be a pulse of long enough duration, and does not have to be a steady state, as would be true of non-latching types.

School me, please.

[R.G.]

Been there, got the T-shirt. Bottom line, use a PIC. You want me to program you one?
Bottom line, you have to put a voltage across the selected coil (or in the right direction) for enough milliseconds, then turn it off. The exact number of milliseconds depends on the relay, but it's in the datasheet for each relay. Or should be.

Last time I did one of these, it had one input with a resistor pullup that got grounded for longer than X time. When that happened, the thing flipped the outputs for the right time and then opened up. Single 8-pin device, needs a 5V supply zener/regulator to run the uC and the relays.
Like I say, want me to program you one?

[digi2t]

Isn't one of the drawbacks of using latching type relays that you give up being able to revert to a bypass condition in case of power failure?

I've been messing with different relay bypass schemes of late, and while the lower power consumption of latching is definitely a draw, not being able to revert to a bypassed condition if power is lost is a spoiler.

[Mark Hammer]

Isn't one of the drawbacks of using latching type relays that you give up being able to revert to a bypass condition in case of power failure?

I've been messing with different relay bypass schemes of late, and while the lower power consumption of latching is definitely a draw, not being able to revert to a bypassed condition if power is lost is a spoiler.

Those are legitimate concerns.  I'll offer the following, though.
1) If there's a power failure, your amp probably isn't going to work, so I wouldn't worry about not being able to switch back.
2) I'm trying to use the relays as non-dedicated switching modules in a larger modular system.  If any single module fails, I simply swap another one.

RG, that's a very kind and generous offer.  Given the state of international mail at this point, however, your speed and graciousness in programming something for me, is no match for lengthy delay in moving the mail across borders and out to residents.

So I'm wondering if there is something I might do with the various CMOS chips I have on hand.  Yes, it wouldn't be as simple or compact, but I have the space (the modules are 4" x 2.5" each ) and I have to use up all those CMOS chips at some point; they've been suited up and sitting on the bench too long. I'm assuming that latching relays existed well before PICs ever came to be, so there must be some other way, in spite of how much more elegant a PIC would be.  And in case anyone thinks it matters, current draw is not an issue as the individual power supplies for each bank/chassis/enclosure of 12 modules are more than enough to handle what I can put in the chassis.

[Groovenut]

You might try this one


I believe I have gotten it to work when using a CMOS inverter chip wired as a flip flop. Just attach the output of the FF in place of the switch.