7 replies to this topic

[PRC]

Following a request I have written up a brief outline of a home cooked moisture alarm.

Currently it is posted up on my web site
here

If any other info is desired please drop me a line.

Paul C

[Arnon_Ayal]

Tn'x, very interesting.
I thought to build one by myself but because the audio problem I added I decided to buy one with it.
Can you post more pictures of the circuit in the housing with better point view?

[PRC]

Not of that one sadly !

The D70 housing is all packed up and ready to ship, just waiting payment to clear.

At the time I made two and will install one in my new D200 housing at some point soon.

Asking the piezo audio transducers to work at between 2 and 3v is quite a big ask. I ran out of interest in cooking up a cct to stabilize the oscillator which has a tendency to change frequency based on cell voltage. As the piezo's also are very 'peaky' in audio output vs Freq. it became more hassle than it was worth.

It can be done but these LED's put out so much light it would be hard to miss - more so in an ike type clear housing which acts like a light pipe itself.

Paul C

[okuma]

Paul:
Thanks for the diagram. Unfortunately, not having an EE degree it makes no sense to me.

Could you be convinced to rewrite in a step 1, step 2 ....
for the Dummy Diver Corps?

Thanks,
Allan

[Arnon_Ayal]

The easiest way to build a DIY moisture alarm I found is to use a voltage tester as the detector. I mean the ones with the inner circuit not the simplest ones. Its cost 2-3$ and according to my tests it detect water very well.
I tool all the items outside the plastic cylinder and attached to it simple electrodes and tested it.
I decided to buy something else since I wanted audio alarm.

[n de d]

.......... link ............ Water Activated Alarm

Attached Images

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[PRC]

Should work - you may want to add a resistor from the base to Gnd, as it stands the BC109 has a pretty hi input Z and may take off - oscillation could be an issue.

Paul C

[Panda]

Here's a very very simple one.
12v 23A battery, 12V buzzer, wire and heat shrink tube....that's all.
It works beautifully.