Voice Playback Box

The art of "making" presents a degree of creative control not present in other pursuits. Colors, design, space, and aesthetics are all something a "maker" must consider. Thus, when designing Assistive Technologies, colorful, complicated, and expensive technologies come to mind. However, the most effective Assistive Tech doesn't necessarily need to be flashy or exciting - it improves and expands upon existing technology. No project better illustrates this than the Voice Playback Box. Cheaper to assemble than market-price playback machines, and with more capabilities, the Voice Playback Box illustrates both the fiscal and societal good that can come from making.

• Plastic/Wood Box with Detachable Sides (Laser Cut/3D Printed)
• Arduino Nano RP2040
• Adafruit MPR121 Capacitive Touch Sensor
• Adafruit STEMMA Speaker
• Breadboard (the smaller, the better)
• STEMMA QT Pins
• STEMMA Pins
• Pin Wires
• Wire (for extending capacitive touch)
• Super-glue
• Battery pack (optional, for mobile use)

Before placing all of the computer hardware in the box, assemble it outside first to ensure that all components are working properly. Start with placing the RP2040 into the breadbox, and attach the MPR121 to the breadboard via the STEMMA QT port on the MPR121 and a STEMMA QT connection on the breadboard by the RP2040. In a similar fashion, attach the STEMMA speaker to the RP2040 using a "STEMMA to pin" cable. Finally, saucer your conductive wires to the desired hole in the MPR121, to carry the capacitive touch ability to the exterior of the box. Once the RP2040 is attached to a computer, or hooked up to power, the computer components should be ready for physical assembly.

In terms of code, the Voice Playback Box is relatively easy to initialize. First, the following modules must be imported: board, time, adafruit_mpr121, digitalio, MP3Decoder (from audiomp3), and PWMAudioOUT (from audiopwmio as AudioOut). Following this, one simply needs to define an i2c connection with the MPR121, and then define the capacitive touch pad as the MPR121 at the i2c address. To enable a sound output, the audio must be defined at its location in the board, D3 in this case. From here, one must create a function to play MP3 files, using the imported modules and decoder. Finally, in the "while-true" loop, a the MP3 function ("play_MP3") is called upon to play a specified sound, depending on what touch pad was interacted with.

Place your assembled computer components inside the 3D printed/laser cut box, and carefully drill a hole in the side (corresponding to the location of the RP2040's ports and/or the box's battery). Drill four more holes in the lid of the box, and string the soldered capacitive touch wires to the exterior of the box. Glue the top of the box down (if necessary). Optionally, you can attach the exterior end of the wire to capacitive touch tape/paint.

As the Voice Playback Box uses MP3 files for audio playback, use an online MP3 recorder tool to record audio as an MP3 file. The Online Voice Recorder website (https://online-voice-recorder.com) provides a fast, free, and easy-to-use platform for this exact purpose. Connect the RP2040 to a computer, and save the desired MP3 file in the "sounds" folder. It is important to do this, as this is the folder in which different voices and recordings will be saved.

Once again, sometimes the most useful forms of Assistive Technology are those which improve upon pre-existing technology. The Voice Playback Box is equipped to handle several upgrades, including...

• Rechargeable power source
• Motion detection
• Higher-quality speaker

... and due to Moore's Law (2 years, costs halved), prices should continue to decrease!