Design a distance warning: an ultrasonic sensor and a buzzer or LED that warns sooner and harder as something gets closer, tested at each band edge.
Reversing cars beep faster as they get closer to a wall. Can you build one, and prove it warns at the right distances?
Client: a family whose car has no reversing sensor. Context: a model on the bench (a ruler and a box stand in for the car and the wall).
Brief: an ultrasonic distance sensor measures in centimetres. Off when the distance is over 100 cm, beeping (blinking) from 30 to 100 cm, steady under 30 cm. Kit parts only (HC-SR04 sensor, piezo buzzer or LED); USB power.
Inquire: Read the brief: who it is for, what it must do (criteria) and the limits (constraints).
Develop: Plan before you build: parts, circuit, code and the tests you will run.
Create: Build it, first in the simulator, then for real if you have the kit. Expect a few tries; that is normal.
Test: Run your tests and record what happened, including what failed.
Evaluate: Judge it against each criterion, and say what you would change.
Make your prediction first. Help opens once you've locked it in.
InquireRead the brief: who it is for, what it must do (criteria) and the limits (constraints).
Inquire: the brief
Sort each line of the brief: a criterion (what it must do, which you can test) or a constraint (a limit you must work within)?
Off over 100 cm
Blinks or beeps from 30 to 100 cm
Steady under 30 cm
HC-SR04 sensor and a buzzer or LED from the kit
USB power
DevelopPlan before you build: parts, circuit, code and the tests you will run.
Develop: plan before you build
On the real sensor, pulseIn measures the echo time; distance in cm ≈ time (µs) ÷ 58. Tinkercad's ultrasonic sensor lets you drag the object to set the distance.
Try it yourselfYour edits are saved in this browser.
Here the knob reading stands in for the distance in cm. Write the bands so all six tests pass.
Use the board. This ticks when you get there.
CreateBuild it, first in the simulator, then for real if you have the kit. Expect a few tries; that is normal.
Create: build it
TestRun your tests and record what happened, including what failed.
Test: run your table
EvaluateJudge it against each criterion, and say what you would change.
Evaluate: against the brief
For teachers
A Years 8–9 design project: a parking assistant with an ultrasonic sensor and three warning bands, planned with band-edge tests, prototyped on the board, built in Tinkercad and optionally on hardware, tested with a ruler and evaluated. About 180 minutes.
I can plan tests for every edge of a set of bands.
I can read a distance sensor and act on it.
I can evaluate my design against each criterion with evidence.
Before class
The sensor code (pulseIn and ÷ 58) is new: give it as a recipe card. HC-SR04 sensors are unreliable on soft or angled surfaces and under about 2 cm; good evaluations mention it. Builds on Arduino › A small system.
If you assess with MYP Design, the steps line up with the criteria:
A Inquiring and analysing: the brief, its criteria and constraints, and research into parts (Inquire).
B Developing ideas: a design specification, the circuit and code plan, and the test table written before building (Develop).
C Creating the solution: building it (in the simulator, then for real), following the plan and justifying changes (Create).
D Evaluating: testing against the specification, recording failures, improvements and impact (Test, Evaluate).
Otherwise, use the same four headings as a simple rubric: each step's reflect checks are the evidence list.
Running the lesson
Develop: ask how many edges three bands have.
Test: rulers out; record the real distance and what the device did.
The hard part (on purpose)
Real ultrasonic readings jump around; students blame their code. Print the readings first.
When students get stuck
The readings jump around. Ask: What does the sensor read when nothing moves? Fix: Average three readings, or aim at a flat, hard surface.
Stretch and support
Stretch: Beep faster as it gets closer, with the delay worked out from the distance (map).
Support: A recipe card for reading the HC-SR04, and the band table half filled.
Where it leads
Other Years 8–9 projects: Smart plant monitor, Reaction game.
Inquire: the brief: Separating what the design must do (criteria) from the limits it works within (constraints) is the first move of any design brief.
Develop: plan before you build: Three bands mean four edges to test; prototyping the bands on the board, with the knob as the distance in cm, gets the logic right before the sensor code.
Create: build it: Building in the simulator first catches wiring and code slips cheaply; the real build then tests the design against the world.
Test: run your table: Running the test table written in Develop, and recording every result including failures, is the evidence for the evaluation.
Evaluate: against the brief: Judging the design criterion by criterion, with evidence from the tests, is what separates an evaluation from a description.
Now you can
Plan tests for every edge of a set of bands.
Read a distance sensor and act on it.
Evaluate my design against each criterion with evidence.