Introduction: Tree of Life (Arduino Capacitive Touch Sensor Driving Servo Motor)

For this project we made a rice-giving tree which comprised of a capacitive touch sensor and a servo motor. Upon touching the mat, the servo motor would be activated and rice (or whatever you want to put in it) will be released.

Here's a short video of how it would work! Enjoy!


Materials Needed:

For the Tree Structure:

  • Corrugated cardboard sheet
  • 4 circular wooden cardboards
  • Plastic sheet or any hollow pole
  • Toilet roll
  • Brown Crepe Paper
  • Masking tape

For the Mat:

  • Cardboard pieces
  • Conductive Fabric (17cm)
  • Additional Fabric
  • 2 Soft styrofoam board

Arduino Set-up:

  • 1 x Arduino UNO
  • 1 x Servo motor
  • 7 x Jumper Wires
  • 1 x Breadboard
  • 1 x 1M Resistor

Cloak Costumes:

  • 2 pieces of Fabric (20 inches each)
  • Sewing machine and thread
  • Pins to secure fabric
  • Fabric Scissors
  • Measuring Tape

Others:

  • Rice grains
  • Food colourings
  • Decorative leaves/flowers

Step 1: Arduino Set-up

Arduino Code

1. First plug in the resistor on the mini breadboard and using jumper wires, connect it to pin 4 and pin 8 of the Arduino.

2. Use jumper wire/alligator clip to connect the conductive fabric (or any other conductive material you wish to act as a touch plate) with pin 8 of the Arduino.

3. Connect the brown (darkest wire) of the servo motor to GND, red wire (power) to 5V and and remaining yellow line to pin 9 on the Arduino.

4. Connect the Arduino to your computer and upload the sketch.

5. Touch the conductive fabric and the servo motor should be activated.

Note: You can alter the sketch based your desired “sensitivity” level for the capacitive touch sensor and also the movement angle of the servo motor.


You can also refer to this simple set-up that's similar to ours:

https://www.instructables.com/id/Arduino-Capacitive-Sensor-in-Less-Than-2-Minutes/

Step 2: Making the Tree Structure

1. Make a hole (radius=5cm) in the 3 circular wooden cardboards.

2. Roll up the plastic sheet into a pole and fit it into the circular cardboard pieces. (Tip: Can use styrofoam pieces to ensure that the plastic sheet fit snugly into the cardboard pieces)

3. Cut out a hole big enough to fit the toilet roll at the bottom of the rolled-up plastic sheet. (Tip: The toilet roll should be able to be tilted at approx 45 degree)

4. Glue this structure to the corrugated cardboard sheet, you can also consider using masking tape to secure the cardboard sheet.

5. Cut a small triangle opening in front for the toilet roll.

6. Paste a brown crepe paper on the cardboard sheet for the trunk look.

7. Cut out some trees using green colored paper or wrap around a leafy vine for decoration.

Step 3: Making the Colored Rice

1. Place some rice grains in a zip-lock bag.

2. Add some drops of food coloring into the bag and shake the bag.

3. Once all the grains are evenly colored, pour it into a place to leave it to dry

4. Repeat for all other food coloring.

Step 4: Prepare the Mat

1. Wrap a layer of fabric over the cardboard base, of a size that is suitable for your project.

2. Get 2 pieces of soft styrofoam for knees to rest comfortably when kneeling to the “Tree of Life”.

3. Wrap soft styrofoam boards with another piece of Fabric, followed by the conductive fabric on the uppermost layer.

Attachments

Step 5: Making of Cloak Costumes

1. Mark measurements of the individual wearing the cloak on the fabric and cut out accordingly for both the body section and hood section. (In our case, we cut a 39 inch by 39 inch size for the body and a 30 inch by 17 inch size for the hood)

2. Secure the position of the fabric to mark precisely the exact areas to be sewn.

3. Sew the fabric accordingly. Attach and sew the hood and the body fabrics together.

Step 6: Our Final Product

In our live demonstration, we told the children participants to wear the Tree Guardian cape before proceeding to kneel before our tree on the kneel pads provided. As mentioned above, the conductive fabric serves as a capacitive touch sensor which activates the servo motor which opens tree funnel to release rice grains. We then gave them some candy to thank them for participating.