Learn how to make a fortune-telling crystal ball that reveals your future when touched!
The project is comprised of three basic parts and can be built in about four hours.
1. Capacitive Touch Sensor:
- 1 - Arduino Uno Microcontroller
- 1 - A to B USB cord (Usually included with the Arduino)
- 1 - Power Supply (I used a cell phone charger cube)
- 1 - 10 Mega Ohm Resistor
- 4 - Male to Male Jumper Wires
- 1 - Breadboard
- Decorative Wire (Note: Must be CONDUCTIVE or it won't work)
- Electrical Tape
2. Audio Player:
- 1 - Serial MP3 Player Module for Arduino
- 1 - Micro SD Card4 - Male to female jumper wires
- 1 - Audio cable
- 1 - Set of speakers (or whatever you want to use to play the audio)
3. The Crystal Ball:
- 1 - Bubble Bowl (I got mine at Michael's -You can also buy "Neckless Acrylic Globes" on Amazon)
- 1 - Crystal Ball Base (I used my cat's food bowl!)
- Hot Glue Gun and Hot Glue Sticks
Step 1: Capacitive Touch Sensor
To make the crystal ball respond when touched, you'll need to build a Capacitive Touch Sensor using some kind of conductive material and an Arduino board.
You'll start building the circuit by connecting the decorative wire to the Arduino. The craft wire I used had a coating on it; so, before I could connect it to the jumper wire, I had to grind off the coating at the end of the craft wire to expose the aluminum underneath. You won't need to do this along the length of the craft wire if you use a large enough resistor (it worked fine with a 10 Mega Ohm resistor!).
Place the two ends of the resistor in separate rows on the breadboard and run jumper wires from each end to the Arduino, one to pin 4 and the other to pin 8. Solder or tape one end of the female to female jumper wire to the exposed end of the craft wire and then insert the other end of the jumper wire into the breadboard along the same row as the end of the resistor that is connected to pin 8 on the Arduino.
At this point, you can move on to step two. However, if you want to test the circuit, place the leads of an LED into two separate rows on the breadboard (noting which row contains the longer pin and which row contains the shorter pin). Run a jumper wire from the short pin to an open GND pin on the Arduino and run another jumper wire from the longer pin to pin 7 on the Arduino. Using the Arduino IDE (which can be downloaded from ), upload the included sketch. If the circuit is functioning properly, the LED should light up when the craft wire is touched!
Step 2: Audio Player
This part is a little bit trickier. You'll need to format a micro SD card with your audio files, add the MP3 Player module to your existing circuit and then modify the code accordingly.
To format the SD card, I used a free application called "SD Card Formatter" that I downloaded from the internet ( https://www.sdcard.org/downloads/formatter_4/index... ). Whatever software you decide to use, the goal is to format the SD card as FAT16 or FAT32. You will then need to create folders on the SD card to put your audio files in (I used five different audio files, so I added five folders named 01, 02, 03, etc.). The audio files need to be in the .mp3 format and they should all have simple names (I named them all A.mp3). For this application, you will only have one audio file per folder as the code accesses the contents of each folder rather than the individual audio files.
To add the module to your circuit, attach jumper wires to the four pins on the MP3 Player module and then connect them to the Arduino.
- RX goes to pin 5 on the Arduino
- TX goes to pin 6 on the Arduino
- VCC goes to the 5V pin on the Arduino
- GND goes to any open GND pin on the Arduino
Insert your formatted SD card into the SD card slot on the module and plug in an audio cable.
Now onto the code....
You can access the original library here: https://github.com/cefaloide/ArduinoSerialMP3Playe...
I've also included the modified code that I used with embedded notes about how to change it depending on your particular application.
Step 3: The Crystal Ball
All that's left is to install the circuit in the crystal ball. I chose to wrap the wire around the outside of the bowl, but you can decorate it however you want (just make sure the wire can be touched).
You can even add fog and blinking lights inside the bowl for some added flare!