Hi All,
 
One may find Wood's Apidictor is an interesting tool to detect early
swarming, queenlessness, etc, but the device is not new, but part of
history. There was an article in the American Bee Journal written by Ing O.
Vancata who designed a device based on Wood's research. The device is small
and built with semiconductors. You can contact him for more information at:
 
Address:
Ing O. Vancata
Vallonvagen 2D
730 50 Skultuna
Sweden
 
 
Reference to his article:
 
Ing O. Vancata (1995) Using acoustic technology to monitor your hives. ABJ.,
Vol. 135, No. 9, pp. 615-618
 
 
There is a US. patent held by Howard T. Kerr, Michael E. Buchanan and
Kenneth H. Valentine (see references) to detect AHB from European honey
bees. It lists publications related to this topic.
 
Some of the bandpass filters (low-pass and high-pass) can be modified to
your needs. The circuit diagram of the device is presented in the paper (no
component values listed). You can use inexpensive operational amplifers and
LED to build your device and display the results of readings. Simple design
of bandpass filters can be found in the book:  Don Lancaster: Active-Filter
Cookbook, Sans, Carmel, ID, USA, 1975, ISBN 0-672-21168-8.
 
You can obtain a copy of the patent for around $15 Can. from a library,
patent office or patent agency.
 
 
The frequency range you may need to detect and display is well researched
and it is not necessary to use sophisticated computer programs or frequency
analyzers to come to the conclusion, but it sounds good. The listed
references and Ing O. Vancata's article will give you the necessary
information.
 
 
In 1992-1993, I designed a similar device to detect queenless hives. I
tested it in Febr.-April, 1993 in an apiary in Calgary. The device was
capable of picking up the sounds of bees from the entrance of hive and based
on the frequency range of the sound  display queenright and queenless hives.
A modified and improved device was planned to be designed for the next
winter period and to test, but my dedication to bee venom collection and its
time requirements never allowed me to proceed.
 
Some of the references listed below can be helpful when you research, design
and build your device. Please note Howard T. Kerr, Michael E. Buchanan and
Kenneth H. Valentine's patent lists 10 more references.
 
 
References:
Claudia Dreller and Wolfgang H. Kirchner (1995): The sense of hearing in
honey bees. Bee World, 76(1): 6-17
 
Howard T. Kerr, Michael E. Buchanan and Kenneth H. Valentine (1989) Method
and device for identifying different species of honeybees. U.S. patent, No.:
4,876,721
 
Hayward G. Spangler (1994) Are the wingbeat frequencies of honey bees an
indicator of populations or behavior? ABJ, Jan, pp. 53-55
 
Adrian M. Wenner (1964) Sound communication in honeybees. Scientific
American, 210: 116-124
 
Adrian M. Wenner (1962) Sound production during waggle dance of the honey
bee. Animal Behaviour, Vol. X, pp. 79-96
 
E. F. Woods (1956) Queen piping. Bee world,  Vol. 37, No. 10, pp. 185-227
 
Honey bee sounds (1989) (in This Week in Science), Science, May, p. 627
 
 
Good Luck.
Sincerely,
Michael Simics
Apitronic Services