Which Solid State relay do I need?

Thread Starter

PepeLapiu

Joined Jul 8, 2019
11
Hey boys and squirrels. First post here. So please let me know if thus us the wrong sub-forum to post my question in.

I'm building an alarm system in my work trailer. It will be powered by a 12V 7Amp lawn mower battery. To the battery is connected the following carpet switch:
https://www.trossenrobotics.com/store/p/3508-Switch-Floor-Mat-14-Inches-x-30-Inches.aspx

The circuit is normally open. When you step on the carpet, the circuit closes, and opens again when you step off the carpet.
On the other side, 3 of these solenoids will be activated:
http://vi.raptor.ebaydesc.com/ws/eBayISAPI.dll?ViewItemDescV4&item=233173662019&category=181878&pm=1&ds=0&t=1553308487000&ver=0&cspheader=1

I would like the solenoids to receive only 2 seconds of power every time you step on the carpet, no matter how long you stay on the carpet. Every time the circuit closes, a relay powers up the solenoids for 2 seconds only.

Can you tell me where I could find such a relay? It would preferably be solid state and panel mount.

Thanx in advance for your help.
 

ericgibbs

Joined Jan 29, 2010
8,838
hi Pepe,
You will require a simple delay circuit between the mat switch out to the SSR control pins.
Are you able to construct a circuit if details are posted.?
E
 

Thread Starter

PepeLapiu

Joined Jul 8, 2019
11
hi Pepe,
You will require a simple delay circuit between the mat switch out to the SSR control pins.
Are you able to construct a circuit if details are posted.?
E
Hi Eric. Try me. If it's not too complicated, I should be able to manage. I was hoping a single relay could do all that
 

Thread Starter

PepeLapiu

Joined Jul 8, 2019
11
Here is my situation.
I already built and entire security system out of various SSRs powered by a 12V battery and activated by a remote. When the motion sensor inside the trailer detects movement, the inside car air horns beep 3 times followed by one very loud beep of the outside train horns.
It worked perfectly except that all the 12V motion sensors I tried are unreliable. They go off when they shouldn't and don't go off when they should.
So in the mean time all my tools got stolen out of my trailer while I was searching for a better motion sensor system.
This is when I decided to beef up my security. Outside the trailer, I installed a light that turns on when it detects motion and two fake cameras which I hope will scare thieves away. And inside the trailer I added 2 deer cams from Cabelas.

Should they decide to break in anyways, I want a floor mat switch in lieu of a motion sensor. Once you step on the mat, you are precisely where I want you. 3 cans of bear mace will spray you and blind you from 3 different sides. But only for 2 seconds. Than the horns go off.
So once you step on the mat, the bear mace triggers are powered up for 2 seconds. Than the train horns are powered up for 30 seconds.
What say you?

Next guy who breaks into my trailer will be made famous on Youtube as I post him
getting bear maced in the face.
 
Last edited:

Thread Starter

PepeLapiu

Joined Jul 8, 2019
11
So basically, once you step on the mat and close the circuit, I want a blinker to provide 2 seconds of power to one thing (the bear mace) followed by 30 seconds of power to the next thing (air horn alarm system).

I built the entire air horn system on my own though I'm not electrical genius. So I should be able to design what you have in mind for me.
 

ericgibbs

Joined Jan 29, 2010
8,838
hi Pepe,
Look at this simple option.
Every time the intruder steps on the Mat, it sends a single 2 sec ON pulse to the SSR.
If he remains standing on the Mat it will not send another pulse, unless he steps Off the Mat and back On, then it outputs another 2 sec pulse to the SSR.

E
 

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Thread Starter

PepeLapiu

Joined Jul 8, 2019
11
hi Pepe,
Look at this simple option.
Every time the intruder steps on the Mat, it sends a single 2 sec ON pulse to the SSR.
If he remains standing on the Mat it will not send another pulse, unless he steps Off the Mat and back On, then it outputs another 2 sec pulse to the SSR.

E
Okay thank you. But unfortunately I don't understand your print. Would you be kind enough to give me a list of all the material needed? Once I buy them all I might be able to figure it out or get an electrician to assemble them for me.
 

Thread Starter

PepeLapiu

Joined Jul 8, 2019
11
Okay. So I don't think I could do that. I just don't understand your drawing.I'll just head to an electrician firm and ask them to build it for me. Unless you know of a place on the net where they can do that for me?
 

marcf

Joined Dec 29, 2014
256
Is there a possibility that someone could disable the alarm system by disconnecting the floor mat switch?

You may want to consider using a NC contact, and a SCR to activate the system. The voltage between the gate and the cathode would be held at 0v (SCR Not Conducting) and would, with proper limiting resistance to the gate allow the SCR to latch into conduction when the protection loop is opened. Introducing a delay in the gate activation could be accomplished with a capacitor.

If the contact between the floor mat and the alarm is broken, either by an attempt to disconnect initiating device (the floor mat switch), or by its activation, the 'indicating appliances' (horn, etc) would activate.

In order to silence the alarm, you would have to manually reset it by removing the connection with a NC PB Switch in series with SCR and the 'indicating appliance' (Horn, mace release, ect)
 

Thread Starter

PepeLapiu

Joined Jul 8, 2019
11
Okay so let me explain the long story.

I built an alarm system for my work trailer. This system is powered by a 12V lawn mower battery and my air compressor.

I used SSRs because I'm not an electronic wizard and those simple SSRs are something I could understand.

The way that this system works is that I lock up the trailer and I activate the system with a wireless key fob. When the system is armed, a beep-beep-beep can be heard. I was hoping that this beeping alone might act as a deterrent.

Two things can trigger the alarm: if the 120VAC to the trailer is cut off, or if the motion sensor placed inside the trailer is activated.

Once the alarm is set off, a trucker's horn inside and a train horn outside are triggered and they are both extremely loud. So much so that every time I tested the alarm, someone would come over to figure out what is going on.

However there are two problems with my alarm system. Firstly, my trailer is often located in remote areas with no one near it to be bothered by the alarm. So thieves would likely not even bother with the alarm.

And the second problem is that I have tried countless 12V motion sensors and they all turned out to be unreliable. They go off when they shouldn't and don't go off when they should.

So the system building was on hold until I could find a solution to the sensor problem. In the mean time the trailer got broken into and all my tools stolen.

So now I decided that I would replace the motion sensor with a floor mat that gets triggered with a 60 lbs pressure.

I'm confident I can hide the floor mat wiring so that nobody will suspect it until it's too late.

Outside the trailer I already installed a fake CCTV camera with a flashing red LED on it. And a light that turns on when you get too close to the trailer.

Inside the trailer, I already have an alarm system that works if I get an appropriate trigger for it, a way to switch it on.

Problem is, if I plug a floor mat to the alarm system, it will only work while you are on the floor mat. As soon as you step off the mat, the alarm system becomes silent again. All the motion sensors I used had a timer that worked around this issue. The floor mat doesn't have this feature. It's just a simple switch.

So what I need is a system that activates as soon as you step on the floor mat. You step on it, and a sequence is started: a relay received power for a full 30 seconds regardless of you remaining on the mat or not.

Forget all the instructions I have explained earlier in this thread. I just need a way that stepping on the floor mat activates power to a relay for 30 seconds. All the better if I can adjust this between 15 and 60 seconds.

One thing for sure: I'm not going to be victim of an other theft of my tools. Never again. I'll sleep in my trailer with a shotgun before I let that happen again.

So essencially, what I need is a way that when you step on the mat, you initiate a switch that activates for 30 seconds. (Or adjustable time). Regardless of you remaining on the mat, or not. Everything else, I can figure out with more SSRs.
 

Thread Starter

PepeLapiu

Joined Jul 8, 2019
11
You could use the single shot timer or the Off delay, a few options.
Max.
Okay Thanx Max.
Just one question to make sure I know what I am looking at.
I was looking at the TRUE OFF DELAY.
Here is the description they give:
Upon application of input voltage, the output is energized. When the input voltage is removed, the time delay (t) begins. At the end of the time delay (t), the output is de-energized. Input voltage must be applied for a minimum of 0.5 seconds to assure proper operation. Any application of the input voltage during the time delay (t) will reset the time delay. No external trigger is required.

So let me rephrase to make sure I understand this relay. When you step on the mat for longer than 0.5 seconds, the output side of the relay is closed. And once you step off the mat, the timer starts. So if you remain on the mat for 5 seconds and the time is set at 10 seconds, the output side is energized for 15 seconds total. Is this correct?
 

MaxHeadRoom

Joined Jul 18, 2013
19,145
Yes.
TRUE OFF DELAY. As the chart shows, the output comes on right away when triggered, the time delay will start at the point of the input voltage is removed.
Max.
 
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