This is a lively tabletop decoration with animated birds in a simulated pine tree. The drinking birds are a type of heat engine--normally their heads go into a cup of water and the evaporative cooling creates a temperature difference between the body and head. In this project, we warm the body with a resistor to create the temperature difference necessary for operation. The top bird has an LED on his hat--what would a tree be without a lighted topper?
CAUTION: The resistors get very warm, children or pets should not touch them. Actually, no body should touch them. You probably don't want your cat or toddler grabbing the birds either.
Six drinking birds scientificsonline.com
Six 3 watt, 12 ohm resistors P12W-3BK-ND digikey.com
Twelve volt, one amp power supply T1027-P6P-ND digikey.com
16 inch by 28 inch (1/2 inch thick) plywood
Two 1" x 4" x 12" boards
#22 stranded wire, about 10 feet (multiple colors would be nice)
Krylon green paint (3 oz. can will work)
Drill and bit that will fit in an 8 inch space (Craftsman 11576 Drill/Driver)
Cut the plywood according to the template.
Pre drill holes near the bottom outer edges of the tree.
Pre drill holes in the 1" x 4" x 12" boards--matching the holes you just drilled in the tree.
Attach the boards to the tree.
The assembly should look like this.
Find a good spot and (using Krylon paint) paint the tree the color of your choice.
Remove the drinking bird body from the feet.
Drill 1/16 inch holes in the legs, just above the cross support.
Find the front two "bumps" on the bottom of the feet. Mark two dots 1/4 inch behind the "bumps." The reason for choosing 1/4 inch is that by doing so, we will end up fastening screws into the center of the 1/2 inch thick plywood.
Drill holes (I used 1/8 inch to match my #4 screws) through the marks made in the last step. Insert the resistor between the legs.
Place the base in an opening and mark the screw positions.
The marked screw positions should be in the center of the plywood.
As mentioned in the introduction, now you need a drill (and bit) that are less than 8 inches long. Otherwise, you can't drill straight pilot holes into the plywood.
Fasten the base of the bird to the tree.
Insert the bird's body into the base. Repeat these steps until all six birds are mounted.
Bend the resistor (or slide the bird up or down) until the resistor just clears the bird's body in the resting position.
Everybody should be in place and free to move.
Solder a piece of #22 stranded wire between bird #1 and bird #2.
Solder a wire between bird #2 and bird #3.
Cut a small piece of Velcror .
Solder a piece of wire between bird #3 and bird #4. Attach one side of the Velcror to the narrow channel of the tree as shown below.
Secure the wire with the other half of the tape.
The wire should be flat and hidden from the front.
Solder a wire between bird #4 and bird #5.
Solder and secure a wire between bird #5 and bird #6.
Solder a wire from bird #6 to bird #1 (the places where no wire is yet attached). Secure the upper part of the wire in the existing tape.
You may need to add a piece of tape to secure the wire about halfway down the tree.
Secure the wire near bird #1.
Add a wire to the left side of bird #3. This wire will cross the tree and extend about 15 inches behind the tree.
Attach another wire to the right side of bird #1. This wire will extend behind the tree about 15 inches.
Secure the wires (from bird #3 and bird #1) as they exit the tree.
Slide an LED onto a #1216 battery (long LED lead goes to + side of battery).
Cut the excess wire from the LED. With packing tape, secure the LED to the battery (making sure the LED is illuminated).
Tape the LED assembly to the top of bird #6's hat. This must be carefully balanced, or the bird will not return to the upright position after a "bob."
The light should be shining toward the front!
Attach the 12 volt, one amp power supply (DC or AC--doesn't matter) to the two wires which extend beyond the tree.
Schematic is shown below--each 3 watt resistor is subject to about 1.5 watts of energy in this configuration.