diy microwave alarm

You would need an array, and if CCTV breaks the budget than PE beams are out of the question.

Reply to
G. Morgan
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You are not going to cobble something together less expensively than you can buy off the shelf. No reverse engineering necessary, it's already

*engineered*.

You seem unwilling to pay for a proper system, prepare to lose some strawberries :-)

Reply to
G. Morgan

oh, my bad, I thought CCTV would just be more expensive than PE. After all, I thought, PE is just an infrared emitting diode on the one, and a receiving photo diode on the other side.

But maybe this is something useful?

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It would only require 6 of those sets to cover al sides...

Totalling about $380, wiring excluded!

Reply to
joe hey

Oh, and solar panels for power, batteries for during the night. And then have it all stolen one night...

Reply to
joe hey

Forget the last remark. All units can be series-fed through one current source that's on a protected location and I'm sure an 'alarm voltage pulse' can be put on the feeding line which will be seen at the source which then would be able to ignite the alarm.

I found this 'DIY' project.

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Double-modulated beam. With a bit of logic it can be made multi-beam, different frequencies, and such that the alarm goes off only when all beams are interrupted.

I wonder if this can be equipped with laser pen-style laserdiodes, so that a high distance can be reached.

Reply to
joe hey

Laser pen diodes are in the visible light spectrum. You'd want something in the infra red range.

But .... I still think you're going to spend a lot more money (and certainl y time) developing this Rube Goldberg device than it would cost to just go out and buy it. I know one thing that you haven't even considered and that is alignment of the beams. You're thinking it's going to be easy ..... (HA !) And don't kid yourself ..... there ARE going to be lots of false alarms regardless ..... and MORE of them if you design it. You've got to guess th at the manufacturers of these devices didn't just think up the idea, put th e device together and it worked the first time. Outdoor sensors take years to develop and refine and even then they are prone to false alarms.

But ...... you sound like you're on a mission to prove something .... so be it. Good luck.

Reply to
Jim

Actually, by that logic you could have had a title of " Battleship for Less Than Price of Dingy and Easier to Assemble."

How about just putting up signs that say, "Toxic Chemical Spill - DO NOT EAT BERRIES."

Reply to
Billy Wains

You really think the Clue by Four approach is going to work?

That's hysterical. It will either keep people out or attract druggies looking to experiment.

Reply to
Bob La Londe
[snip>

Beating the 'you are just too stingy to buy quality' repeatedly is not very helpful. I don't think you understand the economics of the situation.

But hey, thanks anyway chap.

Reply to
joe hey

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Actually I'm not. I'm just trying to explore the options we have. And yes, I did consider alignment of the beams of a laser pen and think it's nearly impossible to do that right. Even if taking some very sturdy concrete posts, put them 4 m deep in the soil for stability, attach strong steel sockets around them holding the mirrors while using fine- threaded screws to adjust them. Keeping them aligned, or even clean after a rain without destroying the adjustment, will certainly be near to impossible.

'Just go out and buy it'? : X6, that's the problem :)

thanks

Reply to
joe hey

I very much do understand the economics, and stingy is not the word I would have used were I to resort to vulgarism.

Now, you could buy the signs, but I suspect you will hand carve them on the ends of stolen produce crates with a nail since you are obviously to cheap to buy a decent knife (or the crates).

Reply to
Billy Wains

And yet you still want to try to design and build one yourself?

Well then ... let's try it this way ...... how much do you think it would c ost you to make a device yourself? How many hours are you prepared to spend experimenting? How long do you think it will take you to produce a viable device? How many strawberry seasons are you willing to sacrifice before the unit works to your satisfaction? What will you have gained if you never (l ikely) get it to work properly? What will you have lost?

Unless you're not telling us all the details .... with the information at h and so far ..... well ... I won't say it again but .... you know what I'm g oing to say .....

And ........ I really think that even with a professionally manufactured de vice, you'd still have an unreliable system. Outdoor sensors are just ..... plain and simple ... unreliable.

How about some good watchdogs with one of those electronic dog fence thingi es and collars? You'd just have to be sure the dogs are meat eaters and not vegetarian.

Reply to
Jim
[snip>

All extremely good points. Thanks.

I guess fencing with high (but safe) voltage on the barb wire with tripping alarm is the most viable solution.

Thanks again.

Reply to
joe hey

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