Tactile Electronic Communication Board (Aided AAC)

Introduction

The objective of this project was to create an interactive Augmentative and Alternative Communication (AAC) tactile board that a young man in our community, who is non-verbal, could use to express what he wants/needs by pressing the associated 3D printed tactile symbol that would play a recorded voice associated with the object he wants/needs. The main soundboard would be divided into 8 symbols, and a few of those 8 symbols would have their own static subset. In total, for each set, there will be one main soundboard and 3 sub-sets with only symbols attached.

For example, if our client chose the symbol for food on the main soundboard, it would play a voice recording of "food". Then the subset of different food items he enjoys eating could be brought to him to allow him to choose between additional options.

For Symbols

• 3D Printer
• 1 12oz Filler Primer
• Acrylic paint
• 4 Paint brushes
• 1 12oz Clear Coat

For Resin Molding

• 16oz Resin
• 16oz Hardener
• 5 Wooden sticks
• 2 100ml Cups
• 3.5 cm Resin Molds
• Lighter (Optional)
• Toothpick (Optional)

For Electronics

• 1 Electronic Soundboard
• 9 Breadboard
• 1 On/Off Switch
• 32 Wires
• 8 2-Pin Buttons
• 1 Speaker
• 1 Supplementary Amplifier Chip
• 1 Battery Backpack
• 1 Battery
• 1 Soldering Iron
• Solder

For Woodworking

• Laser Cutter
• 5 Birch plywood (3/4in x 2ft x 4ft)
• Glue
• 2 Wood Clamps
• Sandpaper

Once the objects are loaded into the the 3D Slicer Program of your choice, the max dimension (in X, Y, or Z direction) can be modified to fit your desired button size. For this project, the maximum dimension was 3 inches.

Some of the objects needed to be cut (on X or Y plane) so that a flat surface could be achieved to maximize surface area for adhesion to button top.

Most objects were printed at 0.3mm layer height with 15-20% infill. Rafts were not required, however support material was required only on the shoe object.

Supplementary 3D objects can be found on the open-source website: https://www.thingiverse.com/

Use a 3D printer to print your desired objects.

We used Rust-Oleum’s Filler Primer to coat the surface of the 3D-printed objects as to give the paint a good surface to adhere to. We used two coats of the filler primer to make sure the objects had been completely covered. The first and second layer were roughly applied ten minutes apart since the filler primers dry in ten minutes to touch. The objects were sprayed in a box in a garage so as to be protected from the wind, but still have good air circulation.

We used acrylic paint to give the objects color. Darker colors only need one coat, while lighter colors need several coats of paint.

We used Rust-Oleum’s Matte Clear to coat the surface of the 3D-printed objects so as to protect the paint of the objects. We used two coats of the matte clear to make sure the objects had been completely covered. The first and second layer were applied roughly twenty minutes apart since the matte clear dries in twenty minutes to touch. The objects were sprayed in the same manner as the filler primer.

For hard to print parts, resin curing can be used instead. To resin cure, a silicon mold is needed. We started by mixing a small amount of part A and B of the resin in a 1:1 ratio for 5 minutes. After letting the resin sit for 20 minutes, the air bubbles were removed. A small layer is poured and left to cure for 20 minutes. While the initial layer is curing, another batch of resin is mixed and left to sit for 20 minutes to remove air bubbles. Once the initial layer is gel-like, the part can be pressed into place, and the second batch of resin can be poured over it until the part is fully submerged. Air bubbles can be removed by using a lighter on the surface of the resin or a toothpick. After the resin cures for 25 hours, it can be de-molded and modified.

We soldered pins to the main Adafruit electronic soundboard, including three long pins at Vin, Gnd, and Bus, for the supplementary battery chip. We then plugged it into a breadboard. This served as the central hub for the electronics. Eight other, smaller breadboards are connected to the central one. Each smaller breadboard has one main component: a small 2-pin button. One pin is connected to the electronic soundboard's input pin, and the other is connected to its ground.

Record audio of a person saying the name of each symbol. It is important to match the voice to the relative age/accent/gender of the user.

Plug your soundboard into a computer (using a micro-USB cable that connects to your computer). From here, simply drop your audio files onto it as if it were a thumb drive. The audio files should be named T00 through T10, corresponding to the pin you want them to play from. The files should be .ogg format. We have attached the audio files that we used (which are not properly named here!).

NOTE: When the soundboard is connected to the computer, it will not play audio. It must be connected to a different power source afterward to play the audio files.

Solder the supplementary battery chip on top of the main electronic soundboard (at the aforementioned three long pins). Plug the battery packs into the adapter on the chip. Now, when the electronic soundboard is plugged into a power source, the battery pack charges. When the electronic soundboard is not plugged in, it uses the battery.

On the supplementary battery chip, use a knife or similar object to break the circuit bridge between the two power toggle holes. Then, solder the power button wires into these holes. The toggle buttons now toggle power on and off when using battery.

Place the supplementary amplifier chip onto the central breadboard. From the electronic soundboard, connect either the R or L output pin to the amplifier chip's input pin (A+). Connect the other input pin (A-) to ground. Connect ground (Gnd) to ground. Connect the speaker wires to the chip's output holes and use a screwdriver to secure the connection.

When a button is pressed, the sound should now emit from the speakers.

Using an Epilog Fusion 40 Laser Machine, the birch plywood was cut for precision fit. The cut pieces were assembled together to act as the main soundboard. This step is optional, but we used sandpaper to smooth out the edges.

Here, all the electronic pieces (i.e. the main circuit, buttons, wires, speaker) are assembled and spread apart to visualize how it would look in the soundboard. We did this to make sure the wire lengths and audio file placements were correct.

The laser-cut birch plywood pieces are assembled and held together with glue. The wood clamps are used to help set the glue and the plywood pieces in place. The electronic setup is placed inside the board to help visualize further steps.

The incredibly strong adhesive that was perfect for this job was Gorilla Super glue. It was used to strongly bond the 3D-printed objects onto the appropriate surfaces (the wooden board and the 3D-printed buttons).

We cut cubes of foam out of a larger block; these served as a way for the buttons to be pressed down and come back up. These foam cubes required some trial and error, and each cube acted a little differently. They were generally about 2.5 inches x 2.5 inches x 2.5 inches, although we cut the height of some of them down based on how they performed during testing.

We cut a vertical hole through the cubes (see the images) so that they could be set around the peg on the bottom of the buttons. When the buttons are placed in the woodcut holes, the foam should rest on the breadboards, and the peg should line up directly above the button.

The following pieces are assembled together to give us our final product:

1. The precision cut birch plywood
2. Working electronic circuit with speaker
3. 3D Printed buttons with 3D Printed tactile symbols

Image 1: Core Board (With buttons and speaker)

Image 2, 3 & 4: Area Board (Static Subsets)