Motion activated sprinkler

[Tyler_Durden]

I foresee many possible uses of this little gadget I stumbled upon...

<a href="http://www2.yardiac.com/long.asp?tgs=296091:16502961&cart_id=86991:740884178876&item_id=886" target="_blank">Motion Activated Sprinkler</a>

</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica">
Scarecrow Motion Activated Sprinkler
The Scarecrow is a motion activated sprinkler that chases animals away.

It is a clean and effective alternative to smelly, poisonous, or visually disruptive repellents. Just hook up to your garden hose, plug in the battery and point it over the area to be protected. It's that easy.


How it works
Scarecrow senses animals the same way security lights detect people; movement and heat. When an animal is seen, a valve opens instantly releasing a three-second pulsating spray of water. The combination of the sudden noise, movement, and water frightens animals away. This startling, yet harmless action is a remarkably effective deterrent.

What it needs
9-volt battery power and a hookup to a garden hose. Scarecrows easily last through an average summer's use.

Installation
It's easy! Just install the battery, hook up the garden hose and plant the stake in the ground.

Coverage
Up to 1000 square feet can be covered by one Scarecrow. A 35 foot deep and 45 foot wide 100 degree sensor detection zone provides plenty of garden protection.


</font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">The $65 price tag bothers me a bit... but I can't think of any way to easily improvise something similar in a manner that saves money.

Modification for the device to spray something other than water would be very easy... just hook up a small section of hose (a few inches or more, depending on how much of the chemical you want to spread you have), insert the liquid you want to disperse (be it tear gas or something more lethal), and somehow create some pressure behind it to ensure the chemical is pushed into the device properly. It requires 30-80 psi.

Could probably be easily modified to fire in one direction only (if your use requires it) as opposed to what I assume is a 360 degree spray it does by default.

[hodehum]

The only thing that could stop it from covering 360 degrees (other than the sensor) would be the fact that it can’t turn, this could be solved with a servo type motor and more than one sensor covering different sectors. Although I would have no idea what electronics would be needed to implement this. A better option (although possibly more expensive) would to just have more than sprinkler.

But why would you need one to face more than 90 degrees anyway? Just place one by each entrance way, activate them each night before you go to bed with a switch rigged up by your front door, deactivate them when you wake up.

For a more lethal type fill the tank with ethanol and adapt a lighting mechanism to light just before it sprays. It would only work reliably once, but it would stop anyone approaching the building in their tracks.

Of course you would have to make the senor less sensitive so as to not fry the neighbourhood pets.

[Tyler_Durden]

Yes, I would consider it more of an indoor thing to prevent wasting your chemicals on pests.

I didn't mean modify it so that the sensor detects all directions, I meant modify the spraying mechanism so that it sprays in only one direction, instead of 360 degrees.

Does anyone have any idea how something like this could be improvised?

[PYRO500]

I wouldn't use ethanol, it's flame propegation speed is too slow and it dosen't burn long and hot enough. I would modify it to make it water tight and have it spray toxin possibly a nerve agent.