Circuit Bent Bird Song Calendar

UPDATE: After you read about this project, take a look at my latest effort to bend the birds to my will:
The Birdianoforte!

I read a posting on, one of my favorite circuit bending sites, about bending the Bird Songs 2009 Wall Calendar. Creme DeMentia got some amazing sounds out of the birds, so I had to try my hand at bending it. I jumped right on Amazon and bought one for five bucks. I tore it down as soon as it arrived, but it took me a couple of months to get around to bending it.

Check out this video to hear the weird and wonderful sounds that are possible by bending bird songs.

The calendar is by Les Beletsky and is based on his book "Bird Songs: 250 North American Birds in Song." Here are the 2009 and 2010 editions:

It is a regular wall calendar on top that features one bird per month. At the bottom is a strip of buttons that, when pressed, play the sound of each of the birds. Tearing it apart revealed that there is a speaker on the far right, a pressure switch strip in the middle, and a little circuit board on the left. There is also a battery compartment that holds three watch batteries. Everything is held together with tiny screws and comes apart easily when they are removed.

The pressure switches are a plastic film that terminates in a row of contacts which are pressed against a row of contacts on the circuit board. The switch setup is very simple. Connect one of the 12 contacts to a common contact to play the sound. There is a surface mounted timing resistor on the board that controls the speed of playback and, therefore, the pitch of the sounds.

After playing with it, I decided what I would do. I wanted to be able to hook it up to an amp or effects box, select a sound, trigger or re-trigger the sound easily and control the pitch. I also wanted to be able to control it with my Bender Sequencer.

This is the end result:

Bent Bird Calendar Annotated
Click on the picture for a full-sized, non-annotated version.

A The speaker wires run from the bird board to jack H.
B The bird board itself, which is mounted using two of the mounting screws that had held it in the calendar.
C This is where the timing resistor was surface mounted. There are two wires soldered in its place and connected to terminals J and pot K.
D Battery wires, which connect to the battery compartment from the calendar, which is chopped down and glued to the underside of the protoboard.
E The contact points for the 12 bird sound switches. I really wish they were on .1" centers, but they are metric. There is a little wire soldered to each contact and to the copper strips on the protoboard.
F A switch connects the selected contact point to the common. Press this to play a bird sound. A nice thing about the bird board is that if you press the switch while a sound is playing, it restarts. That is really key because some of the bird songs are rather long.
G The contact points are connected to two rows of six headers. The other side of the header is connected to a common copper strip on the protoboard. The current sound is selected using a jumper which you can see in the picture on the fifth point from the right.
H An 1/8" speaker jack. I want to insert a cautionary note here. You have to take care when connecting speaker-level output to a line-level input. Without voltage dividing resistors the sound will be completely distorted at best and damage the connected device at worst. I blew out my tiny battery powered amp which I have had for 25 years. Lesson learned. :(
I External connector for the trigger switch. I put this in so that I could trigger the sounds using my Sequencer.
J External connector for the pitch resistor. This is also here for controlling the bird sounds from my Bender Sequencer. A regular CV (control voltage) sequencer will not work here. That is why I designed the Bender Sequencer. It has an optoisolated resistor output that can be used in place of any pot.
K This is the pitch control potentiometer to bend the bird songs into new and unusual sounds.

Everything is mounted on a RadioShack prototype board. I love those things and have been using them for years.

This project certainly fits the dictionary definition of a circuit bent device. However, I wonder if purists would decry the fact that the original device was not left intact. Then again, a purist circuit bender is sort of an oxymoron.

On Amazon, the 2009 calendar is down to $3.40, and the 2010 edition is only $4.00. Even if you are not interested in bending it, I highly recommend getting one to hang on your wall.