Making Connections + Modularity

Before you start uploading any Arduino sketches to your board, I'd like to introduce the concept of modularity. Modularity is when a system’s components can be disconnected and reconnected, sometimes in different configurations. Ways modularity can help you while building project:

1) When building wearable electronics, you will need to build many prototypes and may wish to remove and disconnect electronic components from fabric and the body.If sewn down with conductive thread, cutting and then sewing them down again can be messy and painstaking. If you make a component removable, it can be reused over and over.

2) If you are using a component that can not be washed, like a speaker, it will need to be removed before the rest of the project can get wet.

3) Modularity can also help when you run into a problem, making parts of your circuit modular makes it so you can break apart your project into smaller sections to test.

Modularity is achieved by adding connectors between components that you want to make removable. There are different sewable connectors you can buy and there are lots of ways to design your own. In this lesson, I will go over some of the most common (and one not so common) kinds of connectors. To illustrate the concept of modularity we are going to make our LilyPad USB removable. Please note that the connections in this lesson can be applied to any component, not just the LilyPad USB.

You will learn:

+ about different kinds of connections

+ how to sew snaps to your microcontroller to make it removable

Step 1: Materials

+ microcontroller

+ 11 x snaps (stud half)

+ conductive thread

+ regular thread

+ fabric marker

+ felt

+ scissors

+ fabric glue

Step 2: Breadboard and Headers

Prototyping a project means that the project will be evolving over time as you learn what works and what does not. Components will be swapped out, some will be taken away and some will be added to the circuit as you go. You will constantly be connecting and reconnecting to pins on the microcontroller.

With most Arduino boards, like the Arduino UNO pictured, this is achieved by using a breadboard along with jumper cables that have male headers.

What is a breadboard? It's a board that helps you connect wires. The holes you plug into are connected inside with metal so you can connect two components by plugging them in next to one another. It's an essential tool when experimenting with circuits.

Breadboard

Jumper cables

Male headers on the end of jumper cables.

Female headers soldered to UNO board

So, how does this apply to you? The UNO (and similarly built boards) is typically used for learning Arduino, so there is no doubt you will come across this stuff when building. But, you aren't using an UNO, you are using a sewable microcontroller. This means that you will primarily use other means to connect to your board. Let's explore those.

Step 3: Clipping

Alligator leads are used to clip components to one another and sensors to the pins of a sewable microcontroller. You can see that one pin gets crowded easily. This can be remedied by using a breadboard along with alligator clips. Or by making extending the metal pad to something larger, which you will do in a later lesson.

The connection you make with an alligator lead is quick, making it perfect for experimenting. However, be careful while putting clipped together circuits on the body for testing. The connection is not the strongest and will shift or pull apart when too much movement is applied.

Step 4: Sewing

Sewing to the LilyPad and other sewable components are what they are designed for. Conductive thread makes for a strong and flexible connection that naturally integrates with fabric. It's also the best when it comes to strain relief.

The only downfall of sewing your components with thread is that if you want to use the them again, you need to use a seam ripper or pair of small scissors to cut it off.

Seam ripper

Scissors

This can damage your project and leaves broken connections you made need to make again.

Step 5: Soldering

The act of soldering consists of heating up two metal parts that you want to join and using solder (a mix of metal alloys) to melt around and between the two parts, bonding them together.

This makes a more permanent and sometimes more stable connection. In this class, a soldering iron is not required, but it is good to know that this is an option for making connections.

Step 6: Snapping

Snaps are a strong connector used for closing shirts, jackets and lots of other things in the fashion world. They also make a good connector for wearable electronics because they are conductive. If you want to make a component removable, snaps are the way to go. Snaps will be used as the chosen connector in this lesson's exercise to make your board removable so you can use after the class is complete.

If you have a soldering iron handy you can even solder the snaps onto the board instead of sewing.

Step 7: Male and Female Headers

When you start working with electronics, female and male headers become a go-to connector. They take a bit of soldering but are great for making your circuit modular.

Soldering female headers to ribbon wire with heat shrink tubing.

Female headers on ribbon wire.

Soldered male headers on a flex sensor on right, female headers on ribbon wire on left.

The male headers plug into the female headers to make a connection.

Step 8: Crimp Pins

Crimp pins and sockets are great for making wire-to-thread or thread-to-thread connections. You can use a crimping tool to crimp one on, or smash the Jebus out of it with some pliers. If you use pliers I recommend putting some strong glue on there as well.

Crimp pins with a crimping tool.

One male crimp pin with female crimp socket.

Crimping on a socket with a crimping tool.

Crimping on a pin with a pair of pliers.

The pin plugs into the socket to make an electrical connection.

Step 9: Make Your LilyPad USB Removable

This brings us to the hands-on portion of the class. In the next steps, you will make your LilyPad USB removable by attaching the stud half of a snap to the back of each pin. This takes a little bit of work up front, but it's worth it in the end!

Step 10: Trace

Place the board face-up on some felt and trace around the edge. Cut 1/8" - 1/4" outside of the tracing, creating a circle of felt that is a little bigger than the board in size.

Step 11: Mark

Keep the LilyPad on top of the felt and mark the centers of each hole.

Step 12: Sew on Snaps

Before the snaps are sewn to the board's pins, it's easier to sew the snaps to the piece of felt using regular thread first. Remove the board from the felt and put it aside for now.

Thread a needle with regular thread and knot the end. It can help to lay all the snaps down on the felt to get a feel for spacing before you start sewing. It's important that the snaps are not sewn too close together.

Place the stud half of a snap on top of the first mark and thread the needle through one hole. Stitch down the snap by stitching at least twice through each of the four holes. Continue doing this to the remaining snaps until all are stitched on.

Step 13: Clip Tails

Turn over the felt and snip off all the tails to clean up.

Step 14: Sew to Microcontroller

Once all the snaps are sewn onto the piece of felt, they are ready to be connected to the board. Put the felt with the snaps on the back of the board and line the snaps up with the pins.

Start sewing by pulling the needle through a hole in one snap so the knot of the thread is off to the side and out of the way. This also places the knot so you can put glue on it later to secure without interfering with the board or snap.

Push the needle back through the hole to the front of the board and through the hole of the LilyPad pin you are attaching it to.

Make at least 3 small stitches connecting the snap with the metal pad.

Knot when done, keeping the knot off to the side and away from any of the other snaps. I snipped off my tails as I went but you can leave them, glue the knots and then snip like you did with the sewn circuit. This way you can tighten the knots again before gluing them.

Continue to sew the remaining snaps to their matching pins.

Step 15: Secure

Put a bit of fabric glue over the two knots on each snap to secure. Great job! You are now a snap-sewing wizard! You can now also securely snap your microcontroller to any project. Make sure to share your new snap-sewing skills below.

Step 16: Test Your Knowledge

{
    "id": "quiz-1",
    "question": "What does making something modular mean?",
    "answers": [
        {
            "title": "Parts become reusable",
            "correct": false
        },
        {
            "title": "You can easily disconnect and reconnect parts of a circuit that are not washable",
            "correct": false
        },
 {
            "title": "All of the above",
            "correct": true
        }
    ],
    "correctNotice": "That's correct",
    "incorrectNotice": "That's incorrect"
}

{
    "id": "quiz-2",
    "question": "Alligator leads can be quick connections but...",
    "answers": [
        {
            "title": "they aren’t very flexible",
            "correct": false
        },
        {
            "title": "They can slip and disconnect when moved around",
            "correct": true
        },
  {
            "title": "They are have a high resistance",
            "correct": true
        }
    ],
    "correctNotice": "That's correct",
    "incorrectNotice": "That's incorrect"
}

{
    "id": "quiz-3",
    "question": "Snaps make a good connector for wearable electronics because they are strong and...",
    "answers": [
        {
            "title": "sewable",
            "correct": false
        },
        {
            "title": "conductive",
            "correct": true
        },
  {
            "title": "easy to use",
            "correct": false
        }
    ],
    "correctNotice": "That's correct",
    "incorrectNotice": "That's incorrect"
}

Step 17:

How did you do with those snaps? Share your newly removable LilyPad USB below.