Lesson Plan: Chapter 2

Connecting to CSTA Standards

GradesConceptSubconceptStandard NumberPractice
6-8Computing SystemsDevices2-CS-01Recognizing and Defining Computational Problems: 3.3

Recommend improvements to the design of computing devices, based on an analysis of how users interact with the devices.

The study of human–computer interaction (HCI) can improve the design of devices, including both hardware  and software. Students should make recommendations for existing devices (e.g., a laptop, phone, or tablet) or  design their own components or interface (e.g., create their own controllers). Teachers can guide students to  consider usability through several lenses, including accessibility, ergonomics, and learnability. For example,  assistive devices provide capabilities such as scanning written information and converting it to speech.

Connecting to NGS Standards

GradesStandard NumberConceptPractice
6-8MS-LS2-5Engaging in Argument from EvidenceEvaluate competing design solutions for maintaining biodiversity and ecosystem services...Examples of design solution constraints could include scientific, economic, and social considerations

Learning Outcomes/Goals

In the previous chapter, students built a 'firefly trap' that not only did not take into account the needs of the client (the Guide) but also did not account for particular types of fireflies and their specific requirements. By redesigning the trapper to create a refuge, the student is able to rethink how the design process takes user needs and requirements into account.

Students can discuss how various 'green' technologies have actually harmed the environment that they are trying to help. Wind turbines, for example, offer an interesting analysis in that, while providing renewable energy, they also often pose a threat to birds and bats. Hydroelectric dams offer a good source of renewable energy as well, but come at a cost to native fish and indiginous populations.

Students can debate the pros and cons of these type of installations in a class debate, and try to find a consensus on the best way to use the design process to mitigate harms while reaping benefits.

Differentiated Instruction

Lower level studentsHigher level students
Can complete the project recipe in the emulator and explain how they would enhance itCan try the project on a real device and enhance it with other types of sensors that respond to other types' of user requirements

Transfer Learning

Bring the iterative design process into the real world by asking students to observe how devices have been redesigned based on how they are used. An example is the way the iPod evolvedopen in new window over the years. Steve Jobs explains some of the rationale behind the design changes after the iPod mini evolved to the iPod nano in this videoopen in new window. Consider other design decisions and how they were launched, based on user needs.


  • Conditional: Conditionals in programming are elements of code that tell the computer to start a given process as long as certain conditions are met.
  • Operators: A symbol in a given programming language that indicates a type of mathematical operation to perform on elements of the program, such as + or -.
  • HCI: A field of inquiry that studies how humans interact with computers.
  • Servo: A 'servomechanismopen in new window' is any motorized mechanical device that provides feedback, such as opening or closing.


Building on the work done in the prior chapter around building a firefly shelter, students are encouraged to improve their initial design.

Research the ways that engineers build on their ideas by designing, getting feedback, and then redesigning their projects and programs.Write a summary of the effort to redesign the trap into a refuge. Discuss how the previous design was less inclusive than the subsequent redesign and explain how, going forward, new designs can be improved by better understanding users' needs.

Quiz Answers

A servo is used to

a. Control current

b. Turn a switch on or off

c. Open and close a door or latch

The Boolean data type can have one of two values:

a. true or false

b. this or that

c. if or and

HCI focuses on

a. Help desks

b. Various types of sensors

c. Interfaces between humans and computers

More Resources/Materials

Solution Code:

The full solution codebase can be found in the micro:bit web siteopen in new window and on GitHubopen in new window

Assignment and Rubric: Feed Me!

Your firefly shelter is able to sense light and temperature levels in an environment, but one thing it does not provide is nourishment, which was recommended by the Guide. Have you ever wanted to build a “smart” or “connected” feeder for your pet? Now’s your chance! If you can, build a real device that can open and close a pet feeding device based on a button press or on a motion sensor. If you don’t have access to real devices, sketch a paper prototype of how you would build a pet feeder with a servo arm to open a door and dispense food.

Complete this assignment by either building a real device with a servo to feed a real-life pet and documenting it, a paper prototype of the ideal feeder (with its documentation), or a paper prototype of a specialized feeder for fireflies in various stages, also with a design document. Take into account the device’s accessibility, ergonomics, and learnability, and how easily your feeder can be accessed by its target audience.

ExemplaryAdequateNeeds Improvement
The student creates a pet feeder prototype (either using hardware or paper) that includes a design for hardware, software, and at least one other sensorThe student creates a prototype that lacks creativity, does not work well, or one of the required elementsThe student creates only a basic prototype that lacks sophistication

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