Shirt Circuit: DIY Wearable Breadboard Circuits

Shirt Circuit is soft wearable breadboard with modular DIY circuit components that can be snapped onto the shirt by the wearer. The motivation behind shirt circuit is to challenge the 'black box' paradigm in which STEM education is often delivered. This is done through making and playing

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Making:

Shirt circuit comprises of DIY components that children can build collaboratively with the help of their parents, teachers or even other peers. We have broken the making process down into small steps, as well as provided templates that can be printed and used as a guide.

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Playing:

Rather than learning abstract syntax and programming concepts on the computer, we propose that children learn computing and electronics by embodying a micro-controller. In our exploration we combine computational thinking with qualities of play. The idea is for the child to get in character of a micro-controller and perform various logical actions, such as a conditional if-then task in a 'Simon says' manner. The wearable breadboard helps support the narrative which the game master builds, where a child can personify a micro-controller and 'execute’' tasks.

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Shirt Circuit is a project by:

Manasvi Lalwani & Clement Zheng

The current version of Shirt Circuit consists of the following components:

1. A soft breadboard made from felt, conductive thread and sew-on snap fits.

2. Four different modules:

a. A point-to-point wire connector

b. A soft push button

c. A coin cell battery pack

d. A snap on LED

You can refer to the short time-lapse video above to get a sense of the making process!

Soft breadboard

1. A t-shirt of the desired size. Example: http://amzn.to/1RsY2zK

2. A felt sheet, letter-size or bigger. Example: http://amzn.to/1TelF52

3. Conductive thread. Example: http://amzn.to/1LYq4kX

4. Regular sewing thread.

5. 64 x Nickel-coated sew-on female snaps, size 1/0 (it has to be conductive!). Example:http://bit.ly/1p4BUFB

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Modules

1. Stiff craft felt, 6" x 6" sheets. Example: http://bit.ly/1QRw3ct

2. 64 x Nickel-coated sew-on male snaps, size 1/0 (it has to be conductive! The female and male snaps should come in a pair, we will use the female side for the soft breadboard and the male side of the modules). Example: http://bit.ly/1p4BUFB

3. Regular sewing thread

4. Super glue (We like the brush-on types better). Example: http://amzn.to/1QRwX8U

5. Copper tape, 1/4" width. Example: http://amzn.to/1nljvm9

6. ~3 volts T-1 3/4 LEDs. Example: http://amzn.to/21bIAwY

7. Electrical wire (use silicone wires for better flexibility). Example: http://amzn.to/1Qqehjq

8. Coin cell battery holder (NOTE: this instructable was written specifically for the battery holder listed as the example). Example: http://amzn.to/1RMEZmx

9. Coin cell batteries CR2032 (3 volts).

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Tools

1. Sewing needles (the eye should be big enough for the conductive thread but small enough to fit through the sew-on snaps).

2. Scissors.

3. Wire stripper.

4. Multi-meter (to check electrical connections).

5. Soldering iron and solder wire.

6. Helping hands (for soldering). Example: http://amzn.to/1p4HtUw

Laser Cutting

We recommend cutting the felt components with a laser cutter if you have access to one. You can find the PDF for laser cutting attached. Due to the wattage variations between different laser cutting machines, we recommend testing the cuts on a scrap piece of felt. The laser cut outlines provided in the PDF come with small tabs to keep the small parts attached to the felt sheet after laser cutting. This is to prevent them from flying into the machine's ventilation system. You can easily remove the parts from the felt sheet with a pair of wire cutters.

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Manual Cutting

If you do not have access to a laser cutter, you can still use the PDF as a template for cutting the parts. Use a scissors to cut the part outlines, and a hole puncher to punch out the bigger holes in the design. Mark out the sewing holes and lines with a thin marker pen.

We will prepare the soft breadboard in the section.

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Sewing on the female snaps:

With conductive thread, sew the female snaps onto the felt sheet. If you had laser cut the felt, make sure you follow the sewing holes marked out for you. If you prepared the felt manually, ensure you follow the spacing detailed in the PDF. The soft breadboard consists of 8 columns of 8 female snaps. They are spaced 1" apart from each other both horizontally and vertically (measured from the snaps' center to center).

The columns are divided by a channel running horizontally down the middle. Follow the diagram above to sew the female snaps onto the felt with conductive thread. Ensure that you sew the snaps on tightly! This will ensure good electrical conductivity. Once you have sewn all the snaps onto the soft breadboard, use a multi-meter to check that each column of four snaps is connected electrically. If a snap is not connected electrically to its column, try tightening the conductive thread by pulling the stitching from the back of the breadboard.

On the backside of the breadboard, we further secure each female snap by dabbing the stitching behind each snap with superglue.

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Sewing the breadboard onto the shirt:

Once you have checked all the connections, and once the superglue has dried, you can start attaching the soft breadboard onto the shirt.

Straighten your shirt on a nice flat surface, and position the breadboard on the shirt. We used sewing pins to secure the breadboard in place. Once the breadboard is secure, you can start stitching the breadboard onto the shirt. We recommend stitching the middle-horizontal channel first, as that further secures the breadboard's position on the shirt.

In this section, we will prepare the modules, namely, the connectors, the push buttons, the LEDs and battery packs. We have provided schematics above for your reference when preparing these parts.

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Connector

Begin by soldering a strip of copper tape to the back of the male snaps.

NOTE: Ensure that the spacing between the two snaps correspond to the holes in the felt base (they should be 1" apart center to center). Also make sure that the sewing holes on the male snap correspond to the sewing holes on the felt top.

Brush super glue onto the felt top and base and sandwich the male snaps and copper tape between them. Once the glue has dried, use regular thread to sew the male snaps to the felt top. Follow the pattern indicated in the diagram above. Since the two ends of the connector does not need to follow any polarity, we will use a "square" profile.

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LED
Bend the legs of the LED following the picture above. Ensure that the tips of the LED legs are about an inch apart. Take note of the polarity of the legs. The leg on the side of the LED bulb with a flattened edge is the negative leg. Solder the legs of the LED to the back of the male snaps.

NOTE: Ensure that the spacing between the two snaps correspond to the holes in the felt base (they should be 1" apart center to center). Also make sure that the sewing holes on the male snap correspond to the sewing holes on the felt top.

Brush super glue onto the felt top and base and sandwich the male snaps and LED between them. Once the glue has dried, use regular thread to sew the male snaps to the felt top. Follow the pattern indicated in the diagram above. Since the two ends of the connector need to follow the LED's polarity, we will use a "plus" profile for the positive end and a "minus" profile for the negative end.

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Push Button

Begin by soldering a strip of copper tape to the back of each male snap. One snap should have the sticky side of the copper tape facing up, while the other snap should have the sticky side of the copper tape facing down.

Superglue the side felt props to the felt top of the button. The next part is slightly tricky; paste the snap soldered to the copper tape with sticky side up to the felt top, and the snap soldered to copper tape with sticky side down to the felt base. Trim off any excess copper tape. Super glue the felt base to the side felt props. Use a multi-meter to ensure that there is no contact between the two snaps when the button is not pressed; and that contact is made when the button is pressed.

Once the glue has dried, use regular thread to sew the male snaps to the felt top. Follow the pattern indicated in the diagram above. Since the two ends of the button does not need to follow any polarity, we will use a "square" profile.

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Battery Pack

Cut two lengths of electrical wire, approximately an inch long each, and strip the ends of each wire. Solder each wire onto the back of a male snap.

Next, solder the other end of each wire to the sides of the battery holder. Take note of the positive and negative sides (The side in contact with the bottom of the coin cell battery is negative). Super glue the back of the battery holder to the felt base, and twist the wires so that the male snaps rest on the other side of the felt from the battery holder. Once you have positioned the male snaps, super glue the felt top to the felt base.

Once the glue has dried, use regular thread to sew the male snaps to the felt top. Follow the pattern indicated in the diagram above. Since the two ends of the connector need to follow the battery holder's polarity, we will use a "plus" profile for the positive end and a "minus" profile for the negative end.

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NOTE: Make sure you are consistent with the poles when assembling the LED and battery modules. e.g. all positive poles are on the left side and all negative poles are on the right side.

At this point you have successfully created your own Shirt Circuit set!

The images above show two example circuits you can build with shirt circuit; a "bar chart" circuit, and a "looping" circuit. We are still in the process of developing a playing curriculum for Shirt Circuit and we certainly hope to have more examples up on Instructables soon!

We would love to hear what your feedback and ideas about this project, especially how you will use in a classroom or at home!

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Have fun making,

Have fun playing,

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The Shirt Circuit team