Assistive Tech Button Activated LED Matrix Sign Using Arduino

This instructable demonstrates how to create a button activated LED sign that can display a message across the matrix designed to be mounted to a chair. This sign was made for a specific student to allow her to cheer at sporting events via a button press. It will displays the message "Let's Go BC" when pressed.

Materials

Adafruit Mini Skinny Neopixel Strip 2m

Silicone Wiring

Breadboard

Arduino Nano

Alligator Clips

Buddy Button Switch

Mounting System Plate

USB Data cable (USB A to Micro B)

Shrink Tubing

Screws x3

Nuts X3

Washer x3

Power Source

Battery

Tools

Drill

Laser Cutter

Soldering Machine

Hot Glue Gun

Heat Gun

Scissors

Wire Cutters

Wire Strippers

Electrical Tape

Copper Wire

Multimeter

The first step is determining the size and dimensions of your sign. I used 15.5"x10.5" and laser cut the square in dark blue acrylic with a laser cutter. This could be done with another material and tools but for visibility purposes I thought it would be best to make the base with dark blue acrylic. While laser cutting I also cut two 15.5" x 1" rectangles and two 10.5" x 1" rectangles to be used later. Additionally, I cut another 15.5" and 10.5" square in clear acrylic to be used as the top layer. Then use a drill to make 3 holes in the center of the base blue acrylic layer for the chair attachment.

This build uses 2m of LEDs that have 60 LEDs per meter (120 LEDs total). The first step is removing the plastic covering and cutting the LED strip into smaller rows in order to create the Matrix. I cut the LED strip into 10 smaller strips each with 12 LEDs per strip. Next the strips need to be soldered to each other using the silicone wiring to allow them to be placed in a spiraling pattern. To prep the silicone wire, isolate 3 wires out of 5 and cut them to be 3in each. Then use the wire stripper to expose the wiring on each side. Then solder the LED strips together using the silicone wire and copper wiring being careful to make sure the arrow is properly aligned on each set of strips. Also make sure to test each LED strip after soldering to make sure it has been done properly and the wiring isn't touching. You can use the multimeter to check this as well as testing the light strip. Once you confirm it has been soldered properly, slip a 1" piece of shrink tubing over the soldering and shrink it using a heat gun. You can slide the plastic covering back on to the strip at this point as well.

First attach the Arduino Nano to the breadboard. For the LED Matrix connect the red wire to pin H16, the white wire to pin A25, and the black wire to pin I17. Connect the two wires from the button to B20 and A19. You can use hot glue to secure these connections to the breadboard.

Download the code below on your Arduino Nano through Circuit Python on your Laptop or Desktop with it connected to you computer using the data cable mentioned in components. If you need help installing circuit python and downloading the file visit this Tutorial. Make sure to save you file as code.py to your Arduino Nano. This code was created using a 12x12 Matrix in Excel and mapping the letters and their positions specifically for the message "Let's go BC". To create a new message you will need to modify the code.

Once the LEDs are connected and working use hot glue to attach them in an alternating spiral on your sign as seen in step 2. Positioning may vary depending on the size of your sign, but I positioned the LED strips 1" from the bottom and top, and ~1.5" apart on the sign. Then use hot glue to attach the 15.5"x1" and 10.5"x1" pieces facing upwards. Make sure to feed the wire for the LED underneath the side wall before glueing. The clear acrylic piece will then be glued on top completing the sign. Also attach the Mounting System Plate using the screws, nuts, and washers. Connect to power and your sign is ready for action!