On Tue, 25 Jun 2002, Tony Nixon wrote:

>Lawrence Lile wrote:
>>
>> The big  problem is, hummingbirds are fast.   His toy car can lower the
>> trapdoor in several seconds, and by then the wary hummingbird is long gone.
>>
>> What he'd like is a radio controlled remote system that releases the
>> trapdoor instantly.
>
>Spring loaded flap with a solenoid latch comes to mind.
>
>I guess, if the the poor little hummingbird is slightly faster than the
>operators reflexes, then it's likely to be squashed like in a mouse
>trap.
>
>Maybe a micro switch attached to the bait, or activated by weight on the
>floor surface to operate the solenoid.

Last time I checked a hummingbird weighed under 5 grams and the bait
should be a drop of fragrant honey or flower nectar essence (aka perfume)
in a small tube simulating a flower ;-). The thing you could trigger on
would be wing flapping. Up to 200Hz. You can't see the wings when they
flap them, just blue blur. Like a fan turned up high ;-).

Up close there should be a lot of signal out of an electret microphone.
This needs to be tried though.

Peter

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