momentary to constant multiple con

Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=137102
Printed Date: May 14, 2025 at 6:20 PM

Topic: momentary to constant multiple con

Posted By: danton
Subject: momentary to constant multiple con
Date Posted: August 14, 2014 at 10:18 AM

Good afternoon.

Today I bought a Motorcycle alarm system with a remote engine ignition function. I find this function obsolete and want to use it as a remote key.

By pressing the button on the remote twice, the main unit sends a 12v signal for about 10ms.

I want to convert that momentary signal to a constant output of 12v to activate 3 NC relays (or 1 with 6 connections). These 3 NC relays will be connected to the 6 wires on my ignition.

I also would like to use that same signal to kill the remote key.

So in short
1. 12v (momentary) -> 12v (activate constant) -> activate 3 relays (NC)
2. 12v (momentary) -> 12v (deactivate constant) -> deactivate 3 relays (NC)

Thanks!

Danton

Replies:

Posted By: danton
Date Posted: August 14, 2014 at 12:13 PM

I ordered five SPDT Relays and a few diodes to test the setups in the diagrams.

But if anyone has a suggestion please tell!

Posted By: danton
Date Posted: August 16, 2014 at 10:05 AM

Will the following work?

It's based upon the available schematics.

posted_image

Posted By: the12volt
Date Posted: August 17, 2014 at 8:01 AM

The coils of the three relays you've added to the 12V+ output from the pulsed on/off setup need to be wired in parallel, not series, to work.

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Posted By: danton
Date Posted: August 18, 2014 at 1:07 AM

Oké thanks!

In a Dutch forum they are complaining that this has too many relays and will not work.

But they don't have any nice diagrams that are tested

Posted By: oldspark
Date Posted: August 21, 2014 at 6:34 AM

Have a look at my "latching relay" circuit (a single relay) and have that drive the other relays you need.
It may be that 10mS is not enough to actuate the latching relay. In this case there are numerous solutions (RC-transistor or MOSFETs etc) but maybe using a 555 timer as a mono-shot that turns on a transistor or MOSFET or relay to drive the other relays is easy.
But there are so many "short pulsed" trigger circuits available (google).
I've always thought it ridiculous to use more than one or 2 relays for logic or state functions, but I'm not adverse to circuitry and I see the advantages for more [electrical types.
(FYI - I have often been extremely impressed buy the relay circuit presented hereon, and let's not forget the early computers that used relays - nor telephone exchanges. But size, power, wiring complexity etc is not for me.)

PS - see eg interlock / switchbreak

Posted By: danton
Date Posted: October 12, 2014 at 11:37 AM

I have the relays and the switch.

Today I managed to get everything to work except for one thing.

The pulse is too long so it immediately switches the circuit back on.

Is there a way to use the following diagram with an extra relay to switch the circuit off?

posted_image

Posted By: danton
Date Posted: October 13, 2014 at 7:03 AM

Tested the diagram above and it's working perfect.

Need to add a switch or relay to brake the connection, but that won't be a problem.