Final project: plan, build, improve
What you’ll do
Over three sessions your team designs and builds a robot that solves a problem you choose. It follows the full engineering design process: ask, imagine, plan, build, test and improve.
| Session | Goal |
|---|---|
| 1. Plan | Choose a problem, write a proposal, assign roles |
| 2. Build | Build a working prototype and test it |
| 3. Improve | Collect data, fix problems, make it reliable |
Choosing a problem
Good final projects are small, real and testable. Some ideas:
- A robot that waters a plant only when the soil is dry
- A desk robot that tidies pens into a pot
- A line-following “delivery” robot for the classroom
- A light-seeking solar-panel tracker
- A recycling sorter that separates two colours of block
- An alarm that detects an open door and beeps
The proposal
Answer each of these in one or two sentences:
- Problem: what’s the problem, and who has it?
- Solution: what will the robot do?
- Requirements: 2–4 things it must do, measurably (“sorts 8 out of 10 blocks correctly”).
- Constraints: size, budget, parts available, time.
- Parts list: sensors, actuators, controller, power.
- Sketch: a labelled drawing.
- Roles: who does build, wiring, code, testing and documentation (everyone helps everywhere).
- Risks: what could go wrong, and plan B.
Building
- Build the simplest version that could work first.
- Test each part alone (each sensor, each motor) before joining them.
- Keep the engineering log going every session.
Improving with evidence
Run the same test several times, record the results, change one thing, and test again. Your final presentation should show this evidence.
Example: a complete proposal
Problem: Our class plants dry out over weekends. Solution: A robot that checks soil moisture every hour and runs a small pump when it’s dry. Requirements: waters when moisture is below our threshold; never runs the pump for more than 5 s at a time; runs a week on its power supply. Constraints: under $25 of parts; fits beside the plant pot; built in 3 sessions. Parts: Arduino, soil moisture sensor, 5 V pump with a transistor and diode, USB power supply, tubing. Roles: Amira (wiring), Ben (code), Chen (testing and log), Dana (structure and documentation). Risks: water near electronics, so the electronics go in a box above the pot; the sensor corrodes, so it’s only powered when reading.
Example: a test table
| Test | Moisture reading | Pump ran? | Correct? |
|---|---|---|---|
| Dry soil | 820 | Yes, 4 s | ✓ |
| Damp soil | 450 | No | ✓ |
| Wet soil | 300 | No | ✓ |
| Sensor unplugged | 1023 | Yes | ✗: add a check for impossible readings |
Write your proposalEasy
Fill in all eight proposal headings for your team’s project. Ask another team to read it and point out one thing that’s unclear.
Make requirements measurableMedium
Rewrite these vaguely-worded requirements so you could test them: “it should be fast”, “it should sort well”, “it should last a long time”. For example: “completes the course in under 30 s”; “sorts at least 9 of 10 blocks correctly”; “runs at least 2 hours on one battery charge”.
Find the failureHard
Design one test that tries to break your robot (an unusual input, a sensor unplugged, a low battery). Run it, record what happens, and add a fix.
Quick check
Finished this lesson?