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For the box, we cut 2 slightly larger pieces (dimensions: X x Y x Z) and 4 slightly smaller pieces (dimensions: X x Y x Z). The larger pieces make up the top and bottom, while the smaller pieces form the sides.
Once the pieces are cut, glue them together to form the box. Make sure the edges are flush and the corners are square.
Attach the bottom of the box using screws or nails for extra stability. Glue alone can work but might not be as durable.
Cut a slit in the lid to allow coins to be inserted into the box. Make sure the slit is wide enough to accommodate different coin sizes. We used a size of X x Y.
TODO: Add Image
Drill a hole into the bottom of any side of the box to make room for a DC jack. We didn't have a panel mount DC jack, so we used a PCB one and simply glued it into the hole. We also soldered a JST connector to the jack so that it can be easily connected to the electronics, while still allowing the other electronics to be removed from the box for maintenance.
Apply a white base layer of paint to the box. This will make the final colors more vibrant. Acrylic paint is recommended.
Sketch a 16x16 pixel grid on the box. This will serve as a guide for your Super Mario-inspired design.
Fill in the grid with bright colors to create the iconic Mario Question Block design.
Drill a hole into each corner of the box and lid. Insert and glue magnets into the holes. This allows the lid to remain in place, while still being easy to open.
For the electronics setup, you'll need the following components:
- Arduino Nano
- PAM8403 Audio Amplifier Board
- KY-033 Line Tracking Sensor
- Speaker (8- or 4-ohm, rated for 3W or higher)
Connect the components as illustrated in the circuit diagram below:
TODO: Add Circuit Diagram
For our project, we soldered the components onto a perfboard:
Tip: We utilized JST connectors for connecting the speaker, sensor, and power supply to the perfboard. This allows for better maintainability.
The project's software can be found in the src/ directory. It performs the following actions:
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Initialization:
- Initializes GPIO's and serial communication.
- Displays a playful ASCII art message in the serial monitor.
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Sensor Monitoring:
- Continuously monitors input from the KY-033 line tracking sensor.
- Detects objects (e.g., coins) passing over the sensor by detecting a transition from LOW to HIGH on the sensor pin.
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Sound Playback: Once a coin is detected:
- Standard: Plays the classic Mario coin sound effect each time a coin is detected.
- Special: On every n-th coin (configurable), it plays either a One-Up or Power-Up sound effect instead of the standard coin sound. Currently, the Power-Up sound is played on every 4th coin and the One-Up sound on every 10th coin.
At the top of the main file, you can adjust the following parameters:
POWER_UP: Determines the number of coins required to play the Power-Up sound effect.ONE_UP: Determines the number of coins required to play the One-Up sound effect.SENSOR_PIN: Specifies the pin connected to the KY-033 sensor.WAIT_AFTER_COIN: Sets the waiting time between consecutive sound playbacks. This prevents spam if the coin is detected for a longer duration.
We utilize Damellis's PCM Library to handle audio playback. To play a sound, we can use the startPlayback() function, which takes an array of raw 8-bit audio values. The Mario audio samples are stored in the sounds.h file as byte arrays, however, due to copyright restrictions, sounds.h is not included in this repository. Makerspace Members can access the file on our file server. For others, refer to this Tutorial for instructions.
To upload the software to your Arduino Nano, follow these steps:
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Install PlatformIO:
- Download and install PlatformIO as an extension for your preferred IDE (e.g., VS Code).
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Open the Project:
- Launch PlatformIO and open this project by navigating to
File > Open Folderand selecting the project's root directory.
- Launch PlatformIO and open this project by navigating to
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Connect Your Arduino:
- Use a USB cable to connect your Arduino Nano to your computer.
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Upload the Firmware:
- In PlatformIO, click the Upload button (usually represented by an arrow icon) to compile and flash the software to your Arduino.
To securely house the electronics and ensure proper protection, we designed and 3D printed a custom enclosure tailored specifically to our components (i.e. our Speaker, Perfboard etc.). Provided that you likely have different components, you will need to come up with your own enclosure design. This section mostly serves as a reference for members of our makerspace to repair or modify our coin box.
The enclosure consists of three main parts. Click on the links below to download the corresponding .3mf files:
- Back Part: Holds the perfboard containing the Arduino Nano and the Audio Amplifier.
- Front Part: Houses the speaker and the sensor.
- Lid: Covers the enclosure once the front and back parts are assembled.
Secure the perfboard onto the Back Part of the enclosure using M2 screws.
Attach the speaker and KY-033 sensor to the Front Part of the enclosure using M3 screws and a nut.
Note: Do not fully tighten the nut for the sensor yet, as you may need to adjust its position later.
Connect the sensor, speaker, and DC barrel jack to the perfboard.
Screw the front and back parts together using M3 screws. Then insert the assembled electronics into the wooden box. This may require some force. Use two wooden screws from the bottom of the wooden box to secure the enclosure in place through the designated holes.
- Before attaching the lid, power up the electronics and calibrate the sensor sensitivity to detect coins.
- Place the box lid on top of the enclosure.
- Test the sensor by inserting small coins. If the sensor misses any coins, adjust its position by loosening the nut, repositioning the sensor, and then tightening the nut once satisfied.
Once the sensor is properly positioned, secure the 3D printed lid onto the enclosure using three M3 screws and one M2 screw.
