TAMPER ALARM

[bobhenry]

TAMPER ALARM ....
On another thread an alarm system was brought up. I know we can buy car alarms and adapt them but I was trying to go simpler. My question is how to make the alarm continue to sound for 2 - 3 minutes then shutting off after it was tripped by the mercury switch.

Most of us have a battery on-board so a mercury switch could switch on the current when the trailer elevation is changed such as lifting the tongue to hook up the trailer. Once tripped how do you keep the alarm on for a period of time hopefully drawing attention to the activity.

[starleen2]

if you're good with electronics here is a simple circut that i have used a time or two. radio Shack has all that you need (Model: TLC555/TLC555CP
Catalog #: 276-1718 @ $1.69)

This is a simple but effective alarm circuit which can reset its self after a time that you select. it has normally open and normally closed triggers which make this circuit very practical. This alarm has normally open and normally closed triggers. It's on a 555 timer so the alarm will reset it's self after a certain amount of time. The time is adjustable with the variable resistor in the circuit. The alarm has a reset switch which you can replace with a key switch to make it more secure, and you can change the triggers to other types of door or window switched too. The alarm uses a relay which is connected to a siren but you can replace the siren with whatever you want. The circuit is running off 9VOLTS but can range from 4V - 16V.



http://www.electronic-circuits-diagrams.com/alarmsimages/alarmsckt20.shtml

[wannabefree]

If you're bad at electronics you can use a kit. What you want is a timer module. Velleman makes several that would suit your purpose (MK111, only $5 is one), and if you want more they have a basic alarm kit (#K3504). Google "Velleman" for dealers. The timer modules are generally not resettable, so if you trip it you and your neighbors have to listen to it the full 2 or 3 minutes.

I think 20 seconds in a campground would be enough to alienate all your neighbors. javascript:emoticon(':x')
I had a car alarm for a while and ripped it out for that reason.

BTW - these kits go together like tinker toys. A soldring iron and wire snips are all you need... and the ability to follow instructions.