Boat Alarm suggestions?

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meridian

Member
G'day all,
I am thinking of building an intruder alarm for my boat, as I will be travelling north later this year. (Not being racist, just that you can't trust everyone/anyone these days). My mate has gone the simple route with pressure mat, relay, siren and floodlights.

Being a Picaxer from way back, I naturally want to do something more clever. Current thoughts are either ultrasonic or IR. Jaycar sell an u/s transducer (AU-5550, T/R40-16B)which may work. I guess the main issues are what range is achievable, and how can false alarms be eliminated. I don't want to be woken up at 2am because a towel is flapping in the breeze.

Anyway, I would appreciate thoughts from the collective wisdom that resides in this forum.

paulr
 
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jglenn

Senior Member
If it it outside, many things can interfer. If inside, dual sensing PIR and ultrasonic aid reliability. But be aware of the power drain, make sure you are not going to flatten the boat battery if left unattended for a week.

I actually had good results with a home made microphone/opamp/trigger circuit that tripped an ambulance siren. Stopped a burglar from finishing busting thru my apt door. Skill and a little luck..

PIR don't like sunlite on drapes, etc, or cats. Actually, relying on only one technology, unless it is simple, like a breakwire, will lead to false alarms. Use 2 different things that have to agree.
 
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BrendanP

Senior Member
Crow (google) make a sophisticated PIR for harsh situations. I suggest you use it if you want to go the PIR route.

Your friend has the right idea, a pressure mat is a good soloution or a obect placed over a plunge switch, lift the obect the and the switch opens/closes. Simple but thats all you need, you're not trying to secure NORAD. More complexity = more false triggering.
 
D

Dippy

Moderator
I dunno Brendan, if your 'more complexity' makes a smarter device then it will be better.

We had a similar thing with friend's boats on moorings.

I agree with jglenn's comments about sensors i.e. about performance AND power consumption.

We ended up using break-beam and some home-made vibration (inertial) sensors that could fit under the engine cover.

We had the added complication that the boats were moored on a trot and left, potentially, for months unattended.
So, low power was important.
Domestic pressure mats would have been out of the question for our app. - visible and vulnerable.
If you can fit them under carpetting inside then maybe fine.
I think the carpets in his particular boat were bonded down.

But, I guess, if you're touring, then ultra-low power consumption isn't such a problem.
I would avoid PIR for security stuff as said by JGlenn, I completely agree with his description.
We tried PIRs too and had those problems.
The only one that showed promise was made by Pyronix - quite cheap too.
Maybe, as he says, a dual-technology approach would do it.
PIR+U/S or PIR+Microwave.

I've been playing around with short-range Microwave transmitters for detecting people.
The results were good, so maybe microwave would be an option.
People will grumble that microwave can go through fibreglass.
OK, so turn the volume down. Rocket science isn't it.
(Anyway, these m-wave modules would only helpful if you wanted a DIY solution, I assume you want off-the-shelf sensors?)
 
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Andrew Cowan

Senior Member
PIR won't like cold wind draughts. I have had lots of success with IR beams. For simplicity, you can't beat the old pressure pad. Make sure (somehow) you make people see it is alarmed. I'm sure you would like to deter people from going down into the boat, rather than scaring them off once they are in... Better than nothing, though...

A
 
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manuka

Senior Member
Boat = " a hole in the water, surrounded by fibreglass, into which money is poured".

Some years back I recall a Kiwi boating mate with similar needs- in his case rascals were paddling around marina moorings after dark & eyeing up boats for easily removed valuables. He'd had a lot of mindless problems with hs "rum locker" etc being continually plundered, & had hence pondered diverse approaches - GSM especially. The worry (& call out costs) arising from hi tech false alarms however lead him to a dead simple black box, containing little more than a 12V SLA driving a few (solar powered) flashing LEDs. Total costs, maybe US$20, & AFAIK he's not had any problems since. The rationale of course is that idle thieves will consider such flashing LEDs as indicative of a hi tech security system & paddle away towards the next boat.

In some security setups a touch of humour can also work a treat by the way- rather than saying "Armed alert/guard dogs will attack" etc- which may be considered a "Ooh yeah- right" dare by idle minds, consider signs that'll make them leave you alone - "AIDS Research Vessel" or something topical "Obama Trillion Dollar recipient" etc. The dog sign below I personally find both hilarious & extremely motivating.

A typical dry Aussie approach that's emerged in tragic bush fire hit regions tends to show humour as a human coping mechanism - DIY signs up on moonscaped ash covered sites saying "low maintainence property", "recently landscaped", " passive solar achitecture", or even " free firewood"...
 

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R

RexLan

Senior Member
Well not to dampen the project X2 ...lol. I made my alarm system for my cabin in Alaska to ward off bears. and it certainly did work. You can do the same for the boat.

I used a 12V alarm/siren horn like they use on the emergency vehicles ~ $15 at most auto stores.

I used an outdoor motion light, with the two bulbs and reworked it a little inside so it works on 12V. Wire it to battery on the boat and use the output relay to directly drive the alarm and just one of the lights. You need to put a 12v bulb in it of, course. When it triggers it will turn on a light and sound the horn/siren which is up around 130dB! I also ended up having to put a catch diode on it to keep it from oscillating when it shut off.

They don't false easily, waterproof, cheap and rugged. Mine has lasted 20 years so far!

Total project cost was ~ $30 (US) and a couple of hours time. Of course it is always more fun to roll your own.
 
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jglenn

Senior Member
Thanks, Dippy, however I an no expert on alarm systems, just kludged a couple together, the one did save the day. Microwave systems are out there and viable, with some power drain. You might investigate proximity detectors, perhaps electrostatic plates. The military has one that involves a coax cable, with holes punched in the shield (log spacing from source), that leaks some kind of rf field. It can be miles long, surrounding a base. ANYTHING that walks over the buried cable will set it off, even a chipmonk. At the base I saw, they were protecting some rather large bombs, a whole lot of them, so it was no problem to have a jeep full of soldiers with M-16's drive out to check out false alarms.

Might be possible to build your own, with a tuned threshold.
 
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jglenn

Senior Member
HEY! That was a true story. 1000 H-bombs under the Manzano mountains, New Mexico. Here's a circuit that might help: :cool:

http://www.electronics-lab.com/projects/sensors/030/index.html

Everything-that-moves ALARM

A crucial failing of proximity detectors is their unreliable and tricky nature. This is where they are used to detect humans, not to speak of smaller living beings. One common approach is to detect eddy currents in a living body, which are induced in the body through a.c. mains wiring. However, such circuits become altogether unusable in the case of mains failure, or in the absence of mains electricity, or even where adjacent mains circuits are switched in and out.



The circuit of Fig.1 takes the guesswork out of proximity detection by inducing eddy currents in a living being, whether animal or human. Five turns of enamelled copper wire (say 30 s.w.g.) are wound around the area within which detection is to take place (4m x 4m in tests), and an audio signal of about ¼ Watt is pulsed through this, the Tx, coil. A smaller Rx coil (say 100 turns of 30 s.w.g. enamelled copper wire wound on a 150mm dia. former) is used as a pick-up coil. The circuit is adjusted by means of tune and fine-tune controls VR1 and VR2, so that it is deactivated when one stands back from the Rx coil.

A simple clock generator (IC1a-IC1b) and power MOSFET (TR1) are used for the transmitter, and a 7555 timer (IC2) is wired as a sine-square convertor for the receiver. IC2's inputs are biased...
 
M

meridian

Member
Boat alarm suggestions

BrendanP said:
Crow (google) make a sophisticated PIR for harsh situations. I suggest you use it if you want to go the PIR route.

Your friend has the right idea, a pressure mat is a good soloution or a obect placed over a plunge switch, lift the obect the and the switch opens/closes. Simple but thats all you need, you're not trying to secure NORAD. More complexity = more false triggering.
Click to expand...
Thanks for that suggestion, I have looked at the Crow site, and the TL-Express looks pretty good for my purpose. I have requested more info from them.

Thanks to all the others who have offered suggestions. As we live aboard, and use around 150Ah/day, current drain is not an issue. Haven't got the room to carry soldiers, and guns are more problem than they are worth. A bright flashing LED (Picaxe driven of course) might be the simplest and cheapest solution of all!

Cheers
paulr
 
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alband

Senior Member
Since it's a boat, and you're worried about intruders going onto the boat, why not use the fact it is a boat to your advantage.

I'm thinking:

Person goes onto boat, boat rocks a bit (assuming were not trying to booby-trap a ferry) and will sink a bit. Use a float attached to a POT to allow the PICAXE to read the depth. If a code is entered on a keypad then the system wont care for about 1min. If the intruder "rocks the boat" and no code is entered the all hell is let loose (use your imagination for that ;)).

Basically, to sense the person, use some kind of depth measurement.?:)
 
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alband

Senior Member
You'd have some limits that trigger it. e.g:

Code: 
main:    readadc 1,b1
if b1 is more that 20 away from b2 then
let b2 = b1
goto main
I know thats not how to write that middle line, I just knew there is some fancy way of expressing that in 1 line but couldn't remember it. :eek:

Edit: not sure about those chipmunks though, a boat dog perhaps?
 
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jglenn

Senior Member
Is anyone going to try the Electronics Lab proximity loop detector link I posted?

I printed it out, looks simple, may work. If the power drain is not acceptable, the PICAXE could turn it on with a duty cycle, quick enough to detect...

THE CHIPMONK. That was just an example of a small signal generating target.

They can only steal tiny boats that are inland. On Lake Erie here by Ohio, some punks came in by boat to a ritzy marina, a yacht club, and snatched lots of stuff. Even the rich can't protect their property. Need one of those mil Phalanx cannon turrets. Set it for automatic, and get out fast. :cool:
 
M

meridian

Member
alband said:
Since it's a boat, and you're worried about intruders going onto the boat, why not use the fact it is a boat to your advantage.

I'm thinking:

Person goes onto boat, boat rocks a bit (assuming were not trying to booby-trap a ferry) and will sink a bit. Use a float attached to a POT to allow the PICAXE to read the depth. If a code is entered on a keypad then the system wont care for about 1min. If the intruder "rocks the boat" and no code is entered the all hell is let loose (use your imagination for that ;)).

Basically, to sense the person, use some kind of depth measurement.?:)
Click to expand...
Well ... as someone already pointed out, waves rock the boat,particularly where we are now on the Brisbae River with ferries going past every 5 minutes. Also we weigh about 20 tons, so a 80kg person isn't going to change the depth very much.

This does raise the point about *us* getting back on the boat and getting to the alarm switch before it goes off. How about a wireless remote!?!

paulr
 
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BrendanP

Senior Member
I used the Crow PIR in the bush on some video surveilliance gear. I got a bit of false triggering but not much.

That was fully exposed to wind,rain, sun etc. Yet it was sensitive enough that I often got vid of wallabies etc. crossing the field of view of the camera. So I think the Crow PIR will work well in the boat with next to none false triggering.

You can set the PIR via a DIP switch to take multiple hits before it will trigger as well.

Try Mainline Security in Gardenvalle Melb. if you have trouble sourcing the PIR. They distribute Crow.
(Crow is Israeli). Mainline is a trade outlet but will sell to you.
 
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Dippy

Moderator
Obviously it's worth investigating various things if you have the time/budget/patience.

But, IMHO "I got a bit of false triggering but not much" isn't good enough for an alarm.
A couple of false alarms and it will be relegated to the status of car alarms - as in no-one takes any notice ; including the perp.

Having said that, it may still be worth playing with a couple of PIRs (which have a good range of pulse count) as positioning can make a big difference.

If microwave or dual-tech gear in't possible, then I'd be tempted to design my own with a couple of those NAIS (or is it NIAS? Panasonic anyway) and make a 'coincidence' design. That's if time permitted.
Though if practical, I doubt if you could beat a good break-beam design.

Anyway, sounds fun, and I have enjoyed trying to spend your money, so good luck :)
 
M

meridian

Member
BrendanP said:
I used the Crow PIR in the bush on some video surveilliance gear. I got a bit of false triggering but not much.

That was fully exposed to wind,rain, sun etc. Yet it was sensitive enough that I often got vid of wallabies etc. crossing the field of view of the camera. So I think the Crow PIR will work well in the boat with next to none false triggering.

You can set the PIR via a DIP switch to take multiple hits before it will trigger as well.

Try Mainline Security in Gardenvalle Melb. if you have trouble sourcing the PIR. They distribute Crow.
(Crow is Israeli). Mainline is a trade outlet but will sell to you.
Click to expand...
Hi BrendanP,
What model Crow PIR do/did you use? I contacted Mainline Security and Les told me that the TL-Express is obsolete. They now use the Swan for external use. They also have a combined PIR/microwave sensor for about AUD159+GST. As they are not far away in East BNE, I might go and have a look at what they have.

If I want to roll my own, I will still need some device to read the sensor, interpret the data and act accordingly; that could be a picaxe.

paulr
 
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BrendanP

Senior Member
As stated in my post I used the crow unit in the bush fully exposed to the elements and got a bit of false triggering, it wasnt' an issue because the unit was hooked to video recording gear.

I never stated false triggering would be acceptable in this app.

THIS application is INSIDE the cabin of a boat. I believe you will get zero false triggering in this case.

pdf here.
http://www.thecrowgroup.com/files/outdoor_detection.pdf

I used the Double and Dual model.

If mainline dont have get it from amazon etc. out of the US.

Use a picaxe to monitor the NO or NC PIR output. The picaxe will trigger a strobe/siren unit for say 3 minutes when triggered. It will also pulse a LED until reset by you so you know the unit has triggered in your absence. Mainline sell combined 12V siren /strobe units cheap.

Look at oately electronics and buy a reciever/key fob kit with rolling code and hook that to the piacxe too. That way you will be able to remotely arm/disarm the system from the wharf/shore. Make the siren chirp on arm/disarm.

If you need any more advice on the PIR call me on 0429 336 867. I'm near Morwell.
 
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Dippy

Moderator
Ah, are all Crow products dual technology? It didn't get mentiond earlier and I didn't search.

They look good (or should I say "cool" or "awesome"?) :)

They look well worth a playaround.
You could even add a layer of AFA pulse-counting in your own code I guess.
Nice one.
 
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BrendanP

Senior Member
Maybe a LDR hooked to the picaxe so the picaxe 'knows' if its day or night and so pulse counts 'hits' less at night than during the day prior to triggering the strobe/siren.

More chance of a burg at night.

The crow unit has a internal dip switch in it set it to pulse count as well.

Depending how in depth you want to go you could add a simple GSM function to the alarm by gutting a cheap mobile phone, you use the picaxe to high/low the one touch dialling button on the phone that will call you, you see the alarms number come up on your phone and you know its bene triggered.

You pull the key pad off the phone which will expose the metallised surface, you carefully solder onto the surface.
 
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M

meridian

Member
BrendanP said:
Maybe a LDR hooked to the picaxe so the picaxe 'knows' if its day or night and so pulse counts 'hits' less at night than during the day prior to triggering the strobe/siren.

More chance of a burg at night.

The crow unit has a internal dip switch in it set it to pulse count as well.

Depending how in depth you want to go you could add a simple GSM function to the alarm by gutting a cheap mobile phone, you use the picaxe to high/low the one touch dialling button on the phone that will call you, you see the alarms number come up on your phone and you know its bene triggered.

You pull the key pad off the phone which will expose the metallised surface, you carefully solder onto the surface.
Click to expand...
Could you please expand on the pulse counting business? Can you tell it to count x pulses before triggering?

I like the idea of an LDR to tell the difference between day and night, but soldering inside a phone seems a bit more advanced than I am prepared to go. Nice idea though.

Thanks for the info,
paulr
 
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Dippy

Moderator
Can't speak for the Crow unit, but most of the PIRs I've looked inside have a DIP switch so you can select 1,2 and more pulses before a trigger output.

Remember the standard PIR has that fresnel lens. So as a target moves across the field of view the fresnel lens (lots of little lenses) focusses in zones. If you watched the Pyro sensor output on a 'scope you'd see the wave go up and down. Shove that past a threshold filter and you'd see it as on/off pulses. Count the pulses. When it reaches a certain number-of-pulses in a certain time window then Plop!
 
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BrendanP

Senior Member
Dippys has said it all, you would use the count command.


main:
count 1, 5000, b1 ‘ count pulses in 5 seconds
if b1> 3 then goto alarm
goto main ‘ else loop back to start


So in this example the PIR would be hooked to input 1. The picaxe counts how many times in 5 seconds the input from to PIR go high.

Hmmmm, the manual says the command counts the number of low to high transitions. You really want to count hight to low because you should wire the PIR normally closed so it opens the circuit when triggered.

You could just use the 'inc' to increment the value of b1 each time the PIR triggers and then have a line if b1> 3 then goto alarm.
 
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