Hands-on Activity Night-Light Pennant

Learning Objectives

After this activity, students should be able to:

• Explain what microcontrollers do.
• Describe the importance of microcontrollers in engineering and artistic applications.
• Assemble a system based on the LilyPad LilyMini microcontroller unit.

Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

NGSS: Next Generation Science Standards - Science

International Technology and Engineering Educators Association - Technology

State Standards

Materials List

Each student/group needs:

• LilyPad LilyMini ProtoSnap (includes microcontroller, light sensor, mode button, battery, CR2032 battery holder, RGB LEDs), such as DEV-14063 for $15 from SparkFun at https://www.sparkfun.com/products/14063
• sewing needle, such as from a set of five needles for $2 from SparkFun at https://www.sparkfun.com/products/10405
• Pennant Template
• craft felt, one 9 x12-inch sheet makes one pennant
• wooden dowel rod, on which to hang the pennant from felt loops

To share with the entire class:

• conductive thread, 2+ feet per student; such as 30-ft stainless steel thread bobbin for $3 from SparkFun at https://www.sparkfun.com/products/10867
• pens, markers or chalk to trace design on felt
• scissors
• embroidery or sewing thread
• hot glue gun(s) and hot glue sticks
• (optional) assorted additional craft supplies for decorating, such as feathers, sequins and buttons
• (optional) string and push pins, to hang the pennants on a wall

Worksheets and Attachments

Pre-Req Knowledge

Basic understanding of circuits. Ability to hand sew using needle and thread.

Introduction/Motivation

How do we control systems? Most of the time, systems rely on user input to work; like pushing a button or flipping a switch. We can also control systems using a computer, which enables us to give a wide variety of instructions to our systems. Today, we will be using LilyMini microcontrollers to control small lights called LEDs. A microcontroller is a small computer that stores information and commands, so our LEDs can have more advanced behavior than simply turning on and off.

Besides LEDs, what do you think engineers use microcontrollers for? (Discuss ideas as a class.) Microcontrollers are present in everything from household appliances to automobiles! Engineers pre-program the controllers with programming code, so that users can easily control more-complex systems.

Microcontrollers and electronics are being used more often in textiles, fashion and toys. Can you think of any items that contain electronics? (Possible answers: Light-up shoes, shirts and keychains, stuffed animals that move and sing.) Today, you will act as if you are electrical engineers and create hanging pennants that have LED components. The LilyMini microcontroller you will use is specifically for textiles, and you will sew it onto your pennants using conductive thread. Let’s get started!

Procedure

Background

If unfamiliar with e-textiles, take a look at the following SparkFun tutorials,

• LilyPad Basics: E-Sewing
• LilyMini ProtoSnap Hookup Guide
• Sewing with Conductive Thread

Before the Activity

• Make copies of the Pennant Template, one per student.
• Cut the conductive thread into 2-foot (0.6-m) strands, one per student.
• Gather the remaining materials.
• Heat up the glue guns.

With the Students

1. Present to the class the Introduction/Motivation section. Incorporate the pre-activity assessment—a discussion of everyday uses of microcontrollers.
2. Distribute the batteries and LilyMini ProtoSnap boards. Direct students not to break the boards apart (yet).
3. Tell the students: The LilyMini Protosnap has all its components wired together so you can test out the circuit’s functions before you sew. Install the battery and press the “on/off” button located between sew tabs 3 and 4 (as necessary, show Figure 1).

4. Direct students to explore the different modes of the LilyMini by pressing the button and covering the light sensor. Expect them to discover the colors and behaviors for the following three modes:

Mode 1 = white lights; all LEDs on

Mode 2 = magenta lights; LEDs fade in and out in a breathing pattern; when the light sensor is covered, the LEDs fade faster

Mode 3 = cyan (blue) lights; LEDs off; when the light sensor is covered, the LEDs twinkle

5. Review the definitions of outputs and inputs. Ask students to identify the outputs and inputs of their circuits. (Outputs = the LEDs; inputs = light sensor and button.)
6. Hand out the remaining supplies.
7. Have students trace the Pennant Template onto their felt pieces and cut them out.
8. Direct students to break apart the LilyMinis and discard the non-sewable pieces and scraps (see Figure 2). Then remove the battery and set it aside somewhere out of the way.

9. Direct students to arrange their circuits’ components on their felt pennants according to the template’s diagram instructions. Have students trace the circuit to sew, keeping track of positive and negative terminal orientation. Once everything is laid out and the orientations are double-checked, direct students to use drops of hot glue to secure each component in place.
10. Then have students use conductive thread to sew the circuit components to the felt piece.
11. Make sure students loop the thread through each component at least three times to ensure electrical connections. Figure 3 shows an example of sewing tab 1 of the LilyMini to tab S of the light sensor.

12. Direct students to continue sewing the components together according to the template. Have students use one long piece of conductive thread to connect multiple components, such as the negative terminals of the LEDs.
13. Tell the students: After all the stitching is complete, turn over the project and trim any loose thread tails before testing.
14. Have students insert the battery and check all the circuit modes. If any problems are encountered, see the Troubleshooting Tips section.
15. Have students customize and decorate their pennants using whatever craft supplies are available, including cutting and gluing shapes and letters cut from excess felt (trade colors with other students).

   Tips:

• The light sensor must remain uncovered to work!
• Incorporate into your designs the light-up LED locations.
• Covering the LEDs will dull the light, so keep that in mind while decorating.

16. Conclude by having students individually present their pennants to the class, as described in the Assessment section. 

Vocabulary/Definitions

conductive thread: Thread spun of stainless steel (or silver-coated nylon) that carries current like wires so that it can be used to create circuits that are flexible and require no soldering and thus are suitable for textile-based projects that use embedded electronics. Conductive thread tends to be more “twisty,” and so more difficult to sew with than non-conductive (regular) thread.

e-textiles: Clothing or accessories that includes electrical components such as LEDs. Sometimes called electronic textiles, smart fabrics, smart textiles, smart clothing or smart garments.

input/output: The communication between an information processing system (such as a computer) and the outside world. Input is the circuit component that gathers information from the world and relays it to the microcontroller. Output is a circuit component that receives information from a microcontroller and sends it out into the world.

LED: Abbreviation for light-emitting diode, which is a type of semiconductor called a diode that converts electrical energy into light.

microcontroller: A small computer that stores information and commands to control different sensors and boards it is connected to.

Assessment

Pre-Activity Assessment

Think-Pair-Share: Extend the Introduction/Motivation discussion of microcontrollers. Have students think of and then share within small groups their ideas of engineering applications in which microcontrollers might be useful. Discuss as a class.

Activity Embedded Assessment

Monitoring: Walk around the classroom while students sew together the LilyMini components. Help with any troubleshooting needs that arise.

Post-Activity Assessment

Class Presentations: Give students time to show off their completed and decorated pennants and compare their designs. What are some advantages and disadvantages to the way the pennants are designed?

Beyond Pennants: In a class discussion format, ask students: For what other applications engineers might use the LilyMini ProtoSnap?

Safety Issues

• Hot glue may cause minor burns so make sure students handle glue guns with care.
• Sharp sewing needles can cause injury if used carelessly. Advise students to use them with intention and be especially careful around their faces and eyes.
• Breaking apart the LilyMini sometimes results in pieces with sharp edges so alert students to be careful when performing these steps.

Troubleshooting Tips

If a circuit does not light up, try a new battery or check that it is switched on. Then check the sewing for any loose threads or ends that may be touching other parts of the circuit and causing a short circuit.

Activity Extensions

Have students create new pennants without the provided template. Student-made templates reveal their comprehension of circuits and open up the project for more creativity.

Activity Scaling

• For lower grades, pre-cut the felt templates and have students instruct adult helpers on where to place dots of hot glue. Also have adults break apart the LilyMini ProtoSnaps for the students. Spend less time exploring the functions of the LilyMini pre-assembly and provide more time for pennant customization.
• For higher grades, eliminate the provided template and have students design their own circuit designs. Direct students to clearly label the components and require them to get approval of their circuits before they begin assembly.

References

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Contributors

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