Merry Christmas and Happy New Year

Christmas Tree

Let's build a blinking ornament and singing Christmas tree.


Parts List

  1. 8.5" x 11" project printout (Colored or Color In)
  2. 8.5" x 11" Cardboard backing
  3. Paper glue
  4. Arduino Uno or Uno Compatible microcontroller
  5. Uno development shield or Mini Breadboard
  6. 9 LEDs of various colors
  7. HC-SR04
  8. Piezoelectric buzzer
  9. Minimum 24 Male/Female Jumper Wires but up to 42 Male/Female Wires
  10. Six (6) Male / Male Cables may be necessary 
  11. Optional - Double-sided Tape
  12. Optional - electrical tape
  13. Optional Markers or Crayons of the same color as your LEDs

Wiring Diagram



  1. Print out one of the project cut outs
  2. Affix the printout to the cardboard with the paper glue.
  3. Cut the tree shape out.
  4. Color the white circles with the same color of the LEDs you plan to use.
  5. Use a large pin or small nail to puncture two holes in the white circle areas that are spaced apart enough to pass the LED leads from front to back. 
  6. Drill or cut holes in the tree large enough for the HC-SR04 to pass through from the back to the front. The base of the tree is an excellent place for it.
  7. Push the LED leads through the holes made in step 5. 
  8. Connect each lead on the LEDs into the female end of the jumper cables. With 9 LEDs the wiring can be a spaghetti plate. Tape the LEDs to the wires with the electrical tape.
  9. Optional - affix the Uno board with the shield to the back of the tree leaving enough room at the bottom of the tree for the distance sensor.
  10. Connect the buzzer to the project using the jumpers. In this project we used a 5v speaker to make better sound, but a standard 5v piezo works well too.
  11. Connect the wires connected to the LEDs using the wiring diagram above. We like using a shield with a micro breadboard for this project and suggest you do as well.
  12. Connect the USB cable and use the Arduino IDE to upload the code to the board.
  13. You can change the timing of the blinking of the LEDs by changing the second number in the random code statements. You can also change the distance of the sensitivity of the HC-SR04.



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