
Rick asks:
I race homing pigeons for a hobby. Motivating them to come home quickly is very important. I want to simulate the random chipping (clicking / egg movement) associated with a hatching egg. I already have plastic pigeon eggs that separate in half like a plastic Easter egg to put this device into, but I don’t know where to get the device. Any help would be appreciated.
Now there’s an interesting question! While it’s hard to know exactly how a hatching pigeon egg sounds and moves while it’s hatching without gathering data from an actual hatching egg, there are a couple of ways to go about this. One possibility would be to simply glue a vibrating “pager” motor to the inside of the egg. This way, when powered on, the motor will vibrate the egg. Using a microcontroller like an Arduino or ATtiny you can use PWM (pulse width modulation) to have it move the egg realistically.

Photo by Flickr user Oskay
Another method would be to use a couple of miniature hobby servos to move a small platform that the egg is attached to. This could be used in conjunction with the pager motor to provide more realistic movement and feel for the bird. Again, a microcontroller can be used to control the movement, allowing you to tailor it to your (and the pigeon’s) liking.

Have any more ideas to share with Rick? Please post them in the comments!
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I suspect that any sort of motor would be too powerful for such a purpose. Instead, I’d suggest a small speaker. It could be fed short pulses of DC or low frequency signals, which would be far more subtle and realistic than a pager motor. Everything could be generated by a microcontroller, with a simple transistor acting as an amplifier.
I’d start by attaching a 3 axis accelerometer to a hatching egg and record its actual vibrations through an arduino and a data logger shield. Then I’d play those vibrations back through three tiny hand-wound solenoids oriented along the same 3 axes and installed inside your plastic egg. Subsequent readings of the fake egg could be used to compare the magnitude of its movements to the original in order to fine tune it to match. The comparative readings should also help eliminate any differences in movement attributed to their relatively unequal masses.
How about just sticking a Mexican jumping bean inside the egg?
I’d suggest a cheap piezoelectric speaker element glued rigidly to the inside of the egg (maybe with a small U-bracket and super glue?). Add a battery and and a low power 555 set in astable mode at maybe 2-5 Hz to make the speaker click once every second or two. If you glue the battery to the other side of the speaker, for inertial purposes, it ought to act as though something was pecking at the inside of the egg. I’d expect it to be able to run for at least a couple weeks.
If you want to be able to turn it on and off easily, put a reed switch in series with the battery and put a magnet in the bottom of the nest. That way it will only draw power, and work, when you need it to.
—————–
- Possible speaker: http://www.radioshack.com/product/index.jsp?productId=2062402 but without the case.
- A 555 source: http://www.radioshack.com/product/index.jsp?productId=2062595 (data sheet http://www.ti.com/lit/ds/slfs043f/slfs043f.pdf)
- An astable 555 Circuit: http://www.kpsec.freeuk.com/555timer.htm#astable
- And since I’m on a Radio Shack roll… here’s a possible reed switch. I’d probably take off the houseing and glue it to the inside of the egg. http://www.radioshack.com/product/index.jsp?productId=12706328
So you make them think there’s a hatching egg they need to tend to, then drag them far away so they can frantically race home to keep the hatchling from freezing and starving. For “sport.” Hmm.
Here’s an alternative idea: get a cheap AVR microcontroller ($5) and a piezo element with a frequency response wide enough to faithfully reproduce the desperate cries of a vulnerable infant. Make a suitable recording and place it by your baby monitor, set to go off at 3 a.m. Then sit back, crack open a brewski at the appropriate wee hour, and see how fast your wife flies out of bed!
Were it me, I’d be concerned that any form of electromechanical device would generate a strong enough magnetic field so as to interfere with my birds’ senses.
A diaphragm actuator simulates button clicks in mobile devices (haptic feedback). Maybe this could be used for your purpose?
http://www.artificialmuscle.com/products/bayfol-reflex.php
Photo credit? (CC-BY, should have a little attribution…)
http://www.flickr.com/photos/oskay/2121739429/
Photo credit added. Sorry for missing that.
I made a piece once that was supposed to represent a coffee bean that had been colonized by a Mexican Jumping bean moth larva. I hollowed out a coffee bean, and glued a tiny rare-earth magnet inside. A flat coil in the base of the sculpture was driven via a microcontroller and H-bridge to flip the bean around in a vial.
http://www.flickr.com/photos/84221353@N00/3388039977/
A small magnet inside the pigeon egg would probably sound a lot like pecking. I wonder about what blubrick says though, re. the magnetic field. it would be an interesting experiment.
Time to go pneumatic, a plastic beak driven against the plastic shell, controlled by air pressure. Avoids EMF issues, and may actually be more reliable, unless they move the egg around a lot and wonder what the tubing is.
This just goes to show there’s more than one way to do something – thanks for the great suggestions everyone!
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