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Sensing a bird

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Jerry In Maine

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I need to "sense" when a bird land on a perch. This will switch on a dc pump which will spray a fine water mist for a few seconds.

I've considered several ways...everything from having the bird break an infrared beam to having the perch tilt and make/break contacts from the birds weight. Also considered winding the perch with a coil which varies inductance when a bird lands on it.

Whatever I decide on needs to be able to stand up to weather and not false trigger excessively when light, humidity or other enviromental conditions vary.

Any suggestions? This is nothing more than a modern day version of a bird bath...just no water pool that will need refilling, get dirty or harbor mosquitos.


thanks!
 

Jerry In Maine

New Member
not going to "hose 'em down"....
this will have a very fine mist - like what comes out of a Windex Pump bottle.

besides...birds play and bath in the spray from my lawn sprinkler. Even the resident hummingbird takes a bath from it now and then.
 

microtexan

New Member
How about a small micro switch under the perch. When a bird lands on the perch it closes the switch which energizes the pump. Bird flutters in the water, bathes awhile and then flies off, pump stops.:)
 
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Jerry In Maine

New Member
microswitch: that's likely the easiest way...

only concren is the salty air here on Maine's coast (guess I should mentioned that initially). I thought that might give problems with switch contacts.

Maybe a variant of that using a hall effect switch with arelay between it and the pump?
 

Jerry In Maine

New Member
Next question is:

Why the did idea of using a reed switch escape me when I was first thinking of this?

my brain just don't work as well as it used to I guess......:(

thanks blue!
 

PatM

Member
I'll stick with the old fashioned "bird bath"
No mosquitoes if the water is changed regularly.
The birds get a chance for a drink and also can splash around in the water, which they seem to like to do.
I think they like being immersed in the water vs just finding a spray.
When I have a sprinkler out on the lawn, the only birds that frequent it are the Robins, and they are only after the worms that come to the surface.
PatM
 
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Jerry In Maine

New Member
Birds here get all excited with the mist from the sprinkler.
We have a lake just a couple hundred yards away they can use for drinking and dunking - but they act like a fine spray mist is a water park set up just them.
 

ericgibbs

Well-Known Member
Most Helpful Member
Birds here get all excited with the mist from the sprinkler.
We have a lake just a couple hundred yards away they can use for drinking and dunking - but they act like a fine spray mist is a water park set up just them.
hi,
For the amount of water required to produce a fine mist why not leave it 'misting' during daylight hours.?

If water loss is a problem, place some water loving potted plants around the base.
Or catch the used water, filter and remist.

Could be solar powered.!:rolleyes:
 

Jerry In Maine

New Member
The bath will be in view of a large bay window but still some distance from the house.

I'd rather not run a water line if I can cobble togerther a reservoir that I can fill maybe once a week with the hose. The battery that runs the pump will be charged by a small solar panel.

All will be housed in a small cedar "pavilion" and will incorporate a feeder.
 

ericgibbs

Well-Known Member
Most Helpful Member
The bath will be in view of a large bay window but still some distance from the house.

I'd rather not run a water line if I can cobble togerther a reservoir that I can fill maybe once a week with the hose. The battery that runs the pump will be charged by a small solar panel.

All will be housed in a small cedar "pavilion" and will incorporate a feeder.
I dont know if you get much rain in Maine, but the 'roof' could catch rain water for a simple header tank.

Just had the sillest thought, "the rain in Maine stays mainly on the plain".;)
 

RCinFLA

Well-Known Member
Another possible way is an oscillator using a metal rod or wire in/on a wood rod.

It is like a metal detector but E-field instead of H-field mode.

The bird causes a stray capacitance change. This causes the oscillator to go lower in frequency which is detected. Try something in 100 kHz range with low value freq setting cap value so small amount of stray capacitance change cause more freq shift. The higher the frequency of the oscillator the easier to get a detectable shift.

There will be a slight freq shift when wet but should be much greater when a bird is on it.

There is a electronic music synthesizer (which I forgot name of) that works like this. In this case the tone changes as the hand comes closer to disk.
 

Mr RB

Well-Known Member
Birds might be able to hear 100KHz (it could scare them), they can definitely hear high into the ultrasonics. There would probably be some harmonics they could hear or sense.

Personally I'd spend $10 on a Sharp GP2 infrared object sensor;
Pololu - Sharp GP2Y0A21YK0F Analog Distance Sensor 10-80cm

This is exactly what they are designed for, like those hand air dryers in the mens room that sense your hands and make the blower work. The datasheet says it might have some issues in direct sunlight.
 
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Hero999

Banned
Birds might be able to hear 100KHz (it could scare them), they can definitely hear high into the ultrasonics.
I think you'll be all right as long as you stay above 29kHz.
In birds as a whole, the known hearing ranges vary from a lower limit of below 100 hertz to over 29000, though not all birds have this range. The common Mallard (Anus platyrhynchus) for instance has a range from 300 hz to 8000 hz.
The Earthlife Web - Hearing and the Bird's Ear
 
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Jerry In Maine

New Member
There is a electronic music synthesizer (which I forgot name of) that works like this. In this case the tone changes as the hand comes closer to disk.

You're thinking of a Thermim. Thought of that...winding a coil of magnet wire about the perch. I was concerned about temp and humidity changes causing false triggering. I suppose a perch of PVC or similar material would be stable enough...This would be good because of no moving parts.

Perhaps I could calibrate for relative mass to allow a fine mist for birds or a high-pressure stream (or perhaps a shotgun blast) for squirrels.

How would you detect the freq shift, taking into consideration some variance from enviromental changes? Perhaps squaring up the freq and the detecting when it dropped below a given threshold?
 

Hero999

Banned
A simple capacitive proximity sensor will do the job; you can buy these that will give a 0-10V or constant current output. It should be trivial to connect one up to a comparator such as the LM311 which can directly switch a small relay.
 
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