How to make remote controlled latching door trigger siren.

Thread Starter

Sigma229

Joined Apr 17, 2019
18
Hello,

I am new to the forum and need a bit of help if possible.
I just purchased a 12v 1ch relay that comes with 2 button remote.
Button on latches relay on and button 2 latches relay off.
I also have 2 separate 1ch relays.
All are 12vdc if that matters.
I have one 12 volt siren and 1 n/o door contact as well as 1 n/c door contact.
I also have a 12vdc power supply with 12v4ah battery.

I am trying to wire up my shed so if opened while I use button 1 to latch on relay that if door to shed is opened it will trigger the siren to latch on until i press button 2 of remote.
I did electronics a bit in the past but cant remember how to do that.

So can anyone give me a hand / diagram or drawing so I can set it up.
Can't put in normal alarm system so just want something easy and cheap to do.

Thanks in advance
Sigma
 

AnalogKid

Joined Aug 1, 2013
8,534
You are almost there. You need a total of two latch functions, one to enable the alarm system and one to hold the alarm on when triggered. You have the first one. Use your remote controlled latching relay contacts to power the alarm system.

To make the latching alarm system, you need one more relay with a 12 v coil and SPDT contacts.

Please post photos and links to the relays you have.

A separate part of the project - do you have a battery charger for the backup battery?

ak
 

Thread Starter

Sigma229

Joined Apr 17, 2019
18
Here is a schematic as proposed by ak in post #2.
SG
View attachment 175173
You are almost there. You need a total of two latch functions, one to enable the alarm system and one to hold the alarm on when triggered. You have the first one. Use your remote controlled latching relay contacts to power the alarm system.

To make the latching alarm system, you need one more relay with a 12 v coil and SPDT contacts.

Please post photos and links to the relays you have.

A separate part of the project - do you have a battery charger for the backup battery?

ak
Hello,

Thanks for fast reply to my questions.
The Remote did not work it seems so ordered another remote and relay.

I have all kinds of board relays all 12v with no/c/nc

I see someone posted a schematic for me below your post so am reading it now.
I hope to have new remote and relay in about a week as it was special order.

Thanks
Sigma
 

Thread Starter

Sigma229

Joined Apr 17, 2019
18
Here is a schematic as proposed by ak in post #2.
SG
View attachment 175173
Hello sghioto,

Thank you very much for the schematic I understand it and will get a couple diodes as i do not have any yet.

I did some electronics a long time ago but forgot lots.
As I put in reply to ak had remote and or relay problem for it so ordered a new one.
It should arrive in about a week.

If you dont mind me asking what software did you use to create such a good schematic?

Thanks for your help.
Sigma
 

AnalogKid

Joined Aug 1, 2013
8,534
Here is a schematic as proposed by ak in post #2.
Thanks for drawing it up. I think it can be simplified even more:

Alarm in direct parallel with the relay coil. No steering diode.

Switch contacts in direct parallel with the relay NO contacts.

ak
 

sghioto

Joined Dec 31, 2017
1,313
Alarm in direct parallel with the relay coil. No steering diode.
The purpose is to prevent the alarm current from flowing through the door switch that first instance before the relay energizes. Depending on the current rating of the switch and the alarm current may or may not need.:)
SG
 

Thread Starter

Sigma229

Joined Apr 17, 2019
18
Hello,

Ok so with that circuit no matter if door switch open and closed many times alarm signal stays latched?
Then If I want to unlatch i use remote to unlatch?

If I am reading that correctly.

Thanks in advance
Sigma
 

Yaakov

Joined Jan 27, 2019
1,612
Hello,

Ok so with that circuit no matter if door switch open and closed many times alarm signal stays latched?
Then If I want to unlatch i use remote to unlatch?

If I am reading that correctly.

Thanks in advance
Sigma
It would be worth your time to work out how the circuit works for yourself. This isn’t as hard as it may look. You can get help from people here, but if you figure out how the current flows through the circuit you will not only be able to answer your own question, you will be able to work out improvements you might want and troubleshoot problems.

It’s really worth investing the time, it will make you smarter about electronics in the future.
 

Thread Starter

Sigma229

Joined Apr 17, 2019
18
It would be worth your time to work out how the circuit works for yourself. This isn’t as hard as it may look. You can get help from people here, but if you figure out how the current flows through the circuit you will not only be able to answer your own question, you will be able to work out improvements you might want and troubleshoot problems.

It’s really worth investing the time, it will make you smarter about electronics in the future.

Hello,

Ok I will give it a try.

Thanks
Sigma
 
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