Trailer alarm

[gadgets]

Looking for an alarm for my work trailer, something that goes off when the doors are opened, Problem is that I want it to go off when its not hooked up to the nav too (so no power to trailer). I dont want to use wheel clamps etc cos I know I wont bother putting it on if Im just going to the shops for 10mins.
Hopefully someone with a caravan/camper trailer might have some ideas? Thanks

 

[FatBoy89]

Looking for an alarm for my work trailer, something that goes off when the doors are opened, Problem is that I want it to go off when its not hooked up to the nav too (so no power to trailer). I dont want to use wheel clamps etc cos I know I wont bother putting it on if Im just going to the shops for 10mins.
Hopefully someone with a caravan/camper trailer might have some ideas? Thanks

Mate a little 110 decibel piezo will be plenty. Hook it up to a bonnet alarm switch and bolt it the the door.
Run it off a little 12v 7ah battery you can buy from jaycar for as little as $50.00.
The batteries are tiny.

 

[KraftyPg]

What he said but I'll also add that you could easily add a small charger to keep the battery charged whenever it was plugged into the trailer plug of the ute. Those little 7ah batteries will take a trickle charge forever and the only time they will need more than a trickle is if the piezo screamed for too long but even they are low power and you'll get sick of it screaming before it flattens the battery.

 

[FatBoy89]

What he said but I'll also add that you could easily add a small charger to keep the battery charged whenever it was plugged into the trailer plug of the ute. Those little 7ah batteries will take a trickle charge forever and the only time they will need more than a trickle is if the piezo screamed for too long but even they are low power and you'll get sick of it screaming before it flattens the battery.

You'll also have to Fit yourself I switch to turn it of when you're using it.

 

[KraftyPg]

You could set up an auto switch, when it senses that it's been disconnected from the car the alarm circuit kicks in and turns off when it's plugged in. Would just need a voltage sensor on cable from the trailer plug.

 

[Old.Tony]

Something tells me he wants it active even if it's attached. How would you disarm it? Depends on the alarm unit. I have a noisy alarm for computers that is self-powered (uses a 9V battery) and a mill key switch to deactivate it.

I do prefer the idea of trickle-charging it. You could do that through the trailer plug as suggested.

 

[KraftyPg]

Easy disarm, either by remote or the simplest option is a timer circuit, allow 5 seconds between door open and trigger and the owner turns it off manually. If they forget it will soon remind them.

 

[gadgets]

Thanks for the suggestions, I think I might go with a small battery , a low consumption alarm and some sort of small solar panel on the roof to keep it charged when its disconnected. I guess during winter I could just stick a 240 volt charger on it at the weekends.

I cant believe the amount of money we have to spend to protect our own belongings , alarms, insurance, cameras etc. Crazy.

 

[KraftyPg]

You wouldn't need to charge it often unless it went off.

I have a little 12v 1.3ah battery here which powers an alarm which could be modified to do what you want and while it is providing power to the circuitry at all times when the circuit is armed it's drawing next to nothing. If you treated it kind of like a car battery and charged it for even 20 minutes a day when it was plugged in to your ute the battery would last a week providing the alarm didn't get set off, even longer with one of those 7AH ones FB referred to.

Check out Jaycar or the like for a kit I reckon you could do it for about $40, maybe $60 if you brought the 7ah battery which i think Jaycar charge $34.95 for.

 

[gadgets]

Found this one online today , http://www.gettoolsdirect.com.au/toolguard-tg4000-wireless-tool-box-alarm.html might give it a go, battery's last 2 years, when you close the door or lid it memorizes the angle its at, if the door then gets opened it senses the change in angle and goes off, $100, seems like a good looking unit.

 

[KraftyPg]

Seems expensive for something you could do with about $10 worth of bits but I suppose if it works the way the limited information says it does it will do the job.

Given the constant drain and the limited capacity of 3AA's I'd consider their two year battery life fanciful at best, even a torch that doesn't get turned on drains batteries quicker than that

 

[gadgets]

Ya, does seem a little expensive, especially as I need 2 of them, laziness is getting the better of me.

 

[KraftyPg]

If making one isn't an option go and ask you local SuperCrap. Once upon a time I'd have said go to DSE but lets face it if it doesn't come in a box DSE have no idea but SCA sell all sorts of weird shit and they may have some cheap imported thing that will work for next to nothing.