Personal Alarm Beacon Mods

[AKPilot]

I've got a couple of the personal alarm beacons and want to modify them for rocket locators. They're about egg-size now, but would like to modify them, somehow, so they're in a smaller package.

Any ideas?

 

[KDRaven]

The first Idea that came to me was Disasemble. After that it depends on what size the ckt board and componets are.
Just my .02 worth which is not much.

 

[Peartree]

Yup. Take 'em apart. They've got a nice outer shell so they'll fit nice in your pocket without snagging your keys or poking you in unpleasant places. Ditch the shell and the electronics are likely quite a bit smaller.

There may be more to do, but it's a good place to start.

 

[mjennings]

Hey Troy post some pics. I got 2 that are palm sized that I need to knock down. I tryed some window alarms that I got at Home Depot, and I couldn't get enough weight out of them.

 

[powderburner]

Yup, remove the cover.

It only reduces the weight slightly but it adds a lot of installation flexibility.

A few notes--when I took mine apart, I kept the round plastic housing that held the audio device. The housing (or at least the cover) seems to be part of how that little thing chirps so loudly. Reason I know this is because I took one apart completely...and it sounded entirely different.

Also, be careful to keep the little battery compartment thingy in one piece so it will still work. It's a handy little battery clip, you might as well use it.

Once you have the entire thing de-shelled you should make an effort to minimize handling abuse that you place on the whole thing. My experience was that those teeny lead wires break off from the board pretty easily.

 

[mattvd]

Does anyone know where you can simply buy a really loud piezo buzzer? I also used one of the egg-sized personal alarms for a launch this past weekend. I have to say I was less than impressed. What sounded ear-splitting at home was barely audible from more than about 20 feet in the field.

It was a bit windy, blowing away from me, and my old ears ain't what they used to be. So, I am looking for something REALLY LOUD!

Any ideas?

 

[powderburner]

Those personal alarm thingies in the store are probably about as loud as you are going to find without ordering some "industrial"-sized monster that won't fit into your rocket.

In this wonderful modern world of ours, if some manufacturer put a device on the market that generated ear-splitting levels of alarm noise, you can bet it would only be a few days before some scheming miscreant used it to sue for hearing damages. Most manufacturers are smart enough not to put such things on the market (at least, to the general public). Anyway, the alarms are only intended to get your attention from a few feet away, and they do work for that.

Try using fresh batteries for each use; that should improve performance a little.

If you get a larger alarm that puts out more power, you are going to need more/bigger batteries onboard, and the whole thing starts getting bigger and bigger. And you probably still won't hear it from a 100 feet away.

 

[mattvd]

Probably right . . . thanks.

 

[MikeCr]

I've built quite a few different size and shape locators over the years. If you shop around you can definitely find piezo buzzers that are louder than others. I don't remember off hand where I bought the last few but they were definitely louder than the ones I found at RS. Probably the easiest way to go though is by modding a personal alarm.




Mike

 

[Len_Lekx]

I actually keep the plastic cases on mine. Drill a couple of holes, run a kevlar thread through them, and it makes a sturdy attachment point. Also - depending on the way the pull-pin is set up, the case might be necessary.

Of course... mine are set up to activate on deployment - rather than constantly.

 

[powderburner]

I was changing batteries last night on the smoke alarms in our house, and when you plug in the new battery they give out a little two-second "test" alarm. The alarm is pretty loud...and makes me wonder (I don't have the specs anymore for the smoke alarms I bought) if they are any louder than the little "personal" alarms.

Of course, for use in a rocket, you would have the problem of removing this sort of alarm from the rest of an old smoke alarm, and figuring out how to wire it into a new circuit-

 

[Rocketlady]

I actually keep the plastic cases on mine. Drill a couple of holes, run a kevlar thread through them, and it makes a sturdy attachment point. Also - depending on the way the pull-pin is set up, the case might be necessary.

Of course... mine are set up to activate on deployment - rather than constantly.

There's a how-to article here: https://www.napas.net/newsletters.html in the Summer 2008 issue on page 4.

The smallest beepers I've found are the micro ones sold by Pratt hobbies. Basically a piezo beeper with an LED on a battery clip.