As soon as I got my first Lego set as a little kid, I realized I loved building things and turning my ideas into something real.  My love for creativity and design problem solving has driven me to take design and engineering related classes, which have provided me the inspiration, the space, and the tools to let my imagination run wild. 

I have learned a lot and had a lot of fun working through the unique challenges that come with developing assistive tech, and I hope I will have more opportunities to work on this in the future.

Contact Information: name@name.com 

Insert Door Stoppers and Glue Parts Together

• Pick one of the 1.5"x6" strips to be the front one 

  • Carve a little plus-sign at both marked points on it with the center of the cross lined up with the points you marked earlier.

• Press the tip of your door stoppers through both cross-shaped slits so that the stoppers are poking all the way through to the base.

• Then, take the other 1.5"x6" strip and line up your markings with the screws poking out the back of the front strip. Press the screws into the back piece of foamcore so that you sandwich the doorstoppers in between them.

  • Apply a generous amount of hot glue evenly in between the two foam board parts and press them together tightly so that the foam board deforms around the shape of the door stopper base.

• Glue the "door stopper sandwich" down to your baseplate and hold it upright perpendicular to your base. Ensure the ground wire cutout is facing downard against the base.

• Glue the angled support against the base and the door stopper assembly to hold it in place. Again, make sure the wire channel on the support lines up with the wire channel of the stopper assembly before you stick it down.

Run Wiring and Prepare for Soldering

• Prepare ground and output wires

  • Strip both ends of three alligator clips 

    • If you want to try this project without soldering, you will need to leave the clips on your output wires to clip onto the screws

  • One wire will run through the wire channel up to the middle to be your ground

  • The other two wires will attach to the screws sticking out the back to close the circuit and create an output

• Fix the ground wire with copper tape

  • Fan out the stripped end of your ground wire that is facing the front of the add-on

  • Lay down a long strip of copper tape from one end to the other underneath the door stoppers, covering the frayed end of your ground wire in the middle

    • To find out where your door stoppers will contact the copper before you place it down, you can drag the ends of the stoppers in an arc across the foam board base to see where they will touch the copper tape after you place it down

Soldering and JST Connector

If you want to use heat shrink or use other wire managment techniques, read Step 5 before you continue

• Solder the other two output wires to the screws poking out the back. Wrap the stripped wire around the screws and put more solder than you need so that this connection is secure

• Prepare your JST connector for soldering

  • Strip all three wires and separate them

  • (Optional) If you are going to use heat shrink, slip that onto the wires before you solder

• Solder JST connector

  • Solder the left and right output wires onto the left and right wires of the JST

  • Solder the middle ground wire to the middle wire of the JST

3D Printing

Put the 3D file into whatever program you use, and print it out!

The add on works best printed in TPU, since it has a slit down the bottom for you to bend it in half and access the cable management tunnels better. 

Clearing the support out from inside would be impossible without being able to bend it, and having a flexible body made it much easier to access the channels to run the cables through them.

Clean Up the 3D Print and Prep for Soldering

• Clear support filler out of the wiring channels

  • A small flathead screwdriver works great for getting into the thinner channels

  • You may want to use a box cutter to slice out parts of the filler that wont come out with just scraping alone

  • This is where TPU really works to your advantage! Bend and flex the part at the middle to give you access to the inside channel.

    • You won't bend it too far and break it! I got pretty aggressive with it and folded it pretty far on itself without any permanent deformation

    • Scraping at it with a screwdriver won't scratch it like it would stiffer filaments. 

• Prep the buttons and wiring

  • Bend two out of the four prongs on the buttons down to the bottom of the housing. You only need two of them

  • Strip both ends of four breadboard wires

    • Two wires will go to each button - one ground and one output for each button. All four wires will come out of the add-on where the ground wires can be soldered together into one, leaving you with two outputs and one ground

    • If you want to use heat shrink, remember to slip it onto the wires beforehand so you don't solder it all and realize you forgot

  • Thread the wires through the channels so that you have two wires poking out where each button will be

Soldering and JST Connector

• Solder the wires to the buttons

  • Make sure that you don't put globs of solder, because you don't want them touching each other and both solder joints have to fit down in the narrow wiring channel 

  • If you're worried about them contacting each other, you can insulate the solder joints from each other with a little tape or hot glue, but I didn't run into any issues with shorting

• Solder all four wires to the 3 pin JST connector

  • If you are using heat shrink, make sure you have four pieces for this step - two small pieces for your outside JST wires, and one slightly larger one for the middle ground wire. The fourth piece should be big enough to go around all three wires and cover over the other three smaller pieces. You need to insulate these solder joints from each other no matter what, so if you don't have heat shrink you have to use electrical tape instead.

  • Pick one wire from each button to be the output wires. These ones are easy - just solder one output to the left JST wire and another output to the right one

  • Take the remaining two wires and mesh their frayed ends together - these will combine to be your ground wire

    • You will solder these two to your middle JST wire. Go crazy with the solder if you want. Make sure that all three wires are in contact with each other and that it's all held together securely with solder. You can cover your soldering with heat shrink anyway!

Making Custom Button Caps

This is where you get the opportunity to let your creativity out! You can create any cap for the buttons that you want, and make it specifically to accommodate the abilities of the user. As long as you use a material that can be hot glued to the plastic button, you can put almost anything you want. Below I have the instructions to make the caps that I used.

Dixie Cup Button Caps

Materials:

2x Dixie Cup

Box Cutter/X-Acto Knife

Hot Glue

Q-tips

Foam board scraps

Instructions:

• I cut around the bottom of the dixie cup to use the bottom disc of it as the main part of my button

• Next, I cut down Q-tips so that I could arrange four short segments of the firm paper tubes in a square on the underside of the cup base. These serve to make the dixie cup disc more stable and not bend as easily when pressure is applied off center

• I hot glued these in place, leaving enough room in between them for square plastic button cap to still fit in the middle

• Finally, I cut a small dime-sized circle out of foam board and sliced it in half vertically, creating two 2mm thick discs. I glued them onto the middle which improved the durability and stability of the button caps. 

• The caps ended up looking like googly eyes which is what inspired me to add a little smiley mouth to give the add-on some personality

Finishing Touches

Once you have made some button caps, your add-on is done! Now, you can spend time on the finer details if you'd like. Strategic use of heat shrink will make the cable much easier to handle without breaking it, and improve the overall usability of the device. You can always make more button caps as needed - If you have extra plastic button tops, you can of course make new caps to glue onto them, but you can also reuse the ones you have already used before. The hot glue connection is secure, but if you slip a box cutter in between the plastic cap and the homemade one, you can easily scrape off all the glue and stick something else on there for a different experience.

Prep for Soldering

• Strip the ends of two JST connectors opposite to those you used for your add-ons. 

• Strip the ends of six breadboard cables all on one end. Make sure that they all have one stripped end and one end with a male pin connector. These male pins will go into your Arduino to provide inputs once everything is soldered.

• If you are using it, prepare your heatshrink beforehand and slip sleeve over each wire before you solder.

• Also, as seen in the image, I added little non-slip feet just using drops of hot-glue.

Soldering

• Solder the stripped ends of your breadboard pins to the stripped ends of your JST connectors.

• Make sure none of the soldered connections are touching each other. If you aren't using heat shrink, make sure they are insulated from one another using electrical tape. 

Secure the JST Connectors to the Hub

• Take small scraps of foam board and cut them to the same size as the small outlet holes on the hub.

  • These little rectangles should be just slightly bigger so they press fit into the 3d printed holes

  • Cut a small divot along the bottom middle to allow the JST cable to pass through.

• Hold the foamcore around the JST connector and glue it in place with hot glue

  • Make sure your little cable-divot is snug around the JST cable so everything will lay flat when you push it into the hub.

• Glue the foamcore-mounted JST connector into a hole in the hub

  • By gluing the JST connector to a small bit of foamcore, and gluing the foam board to the hub, we create a secure way to attach a JST connector, while still leaving you the option to switch to a different connection type in the future if you want to use a different add-on that supports other types of wiring.

Wiring!

• I reccomend securing your Arduino in place just using two small bits of foamcore glued down to wedge it in. This is an easy way to keep it in place without damaging or gluing it directly, meaning you can use it later.

• Now you have two JST connectors sticking out of your hub, with a mess of wires all inside. Here is how I wired it:

  • The outside wires of my JST connectors, which have been wired to my outputs on my add-ons, I plugged into the digital pins of the Arduino.

  • The middle wires, which have been the ground wires on my add-ons were plugged into the ground pins on the Arduino.

  • You can plug the output wires into whatever digital pins you want, and then map those pins to whatever keys you would like using the remapping functionality.