VCE Systems Engineering Unit 1 — Electrotechnological systems design

Unit of work Stage 6 18 weeks CC-BY-4.0 · Little Bird Electronics

A full semester of Unit 1: students design, produce and evaluate an electrotechnological system that reduces water or energy use. Seven Plug-Run-Play activities — voltage divider, current limiting, light sensing, temperature logging, threshold control, hysteresis and automatic watering — build the skills first, then students run their own design project through the systems engineering process.

Syllabus outcomes

Code	Outcome	Syllabus
VCE-SE-U1-O1	On completion of this unit the student should be able to explain developments in electrotechnology, discuss influences on electrotechnological design, and investigate, define, generate and design an electrotechnological system that incorporates sustainable design concepts.	VCE Systems Engineering (2026)
VCE-SE-U1-O2	On completion of this unit, the student should be able to use the systems engineering process to discuss and apply basic electrotechnological and control engineering concepts, principles and components to produce a system that addresses a sustainability problem, and evaluate the system and their use of the systems engineering process.	VCE Systems Engineering (2026)

Teacher overview

About this unit

Students design, produce and evaluate an electrotechnological system that reduces resource use. Across a semester they learn how components behave, how to measure rather than guess, how to make a microcontroller decide, and then apply all of it to a problem they choose themselves.

The unit is built so the skills come first and the project comes second. Sequences 1-5 are taught, with seven short practical activities (PRPs) that each end in a working circuit. Sequences 6-10 are the students' own project, using exactly the skills they have just built. By the time a student writes their design brief they already know what a sensor can and cannot do, which stops the most common failure: an ambitious brief that the components cannot deliver.

The two diamonds

The systems engineering process runs as two diamonds. The first opens up a problem and narrows to a design brief; the second opens up design options and narrows to one built, tested system. Evaluating, and planning and managing, run across both. It is not a straight line — students will go back to component selection when a subsystem does not perform, and that backtracking is the process working, not failing.

How the semester runs

Weeks	Sequence	Focus
1-2	1	Systems, inputs and outputs; the design brief is issued
2-4	2	How electrotechnology got here, and what it costs
4-6	3	Components, symbols and circuits (PRP 1-2)
6-8	4	Sensing the world (PRP 3-4)
8-10	5	Control, feedback and code (PRP 5-7)
10-12	6	Investigating and defining your own problem
12-13	7	Generating and designing
13-14	8	Planning and managing
14-17	9	Producing and implementing
17-18	10	Diagnostic testing and evaluation

What to assess

Assessment in this unit is school-based and the task types are your decision. The unit produces natural evidence at three points: the design brief and evaluation criteria (end of sequence 6), the design folio and justified preferred option (end of sequence 7), and the finished system with its test data and evaluation (sequence 10). The record of evidence runs underneath all of it.

A note on the record of evidence

Start it in week 1, not week 10. Students who assemble it retrospectively write a story about what they think they did; students who keep it as they go have photographs of the failed version, the test that made them change the threshold, and the reason they swapped components. The second kind is worth far more and takes less effort. Ten minutes at the end of each practical lesson is enough.

Design brief

Design, produce and evaluate an electrotechnological system that reduces the resources a household, school or community uses — water, energy, or both — by sensing conditions and acting on them automatically.

Your system must sense something real about its environment, decide what to do with that reading, and change an output as a result. It must keep working without someone standing over it.

Constraints

Your system must:

use a microcontroller to make the decisions;
take at least one input from a sensor that measures a real physical quantity;
drive at least one output that does something observable;
change its output based on the input, not on a fixed timer;
run safely on low voltage DC — nothing in this unit connects to mains power;
be built and tested within the time, budget and components available.

Criteria for success

Develop your evaluation criteria from the constraints and considerations in your design brief, and from the parameters of the system itself. A workable set covers both the system and the process:

The system

It is operational — it works, repeatably, without intervention.
It senses a real quantity, and you can show the sensor's readings are trustworthy.
Its output changes in response to the input, at a threshold you can justify.
It addresses the resource problem named in your design brief, and you can quantify the saving.

The process

Your record of evidence shows the decisions you made and why.
Your final system differs from your first design in ways you can explain.

Teaching program

1. Systems, inputs and outputs (Identifying & defining)

Teacher

Open with a system the students already trust and never think about: a fridge, traffic lights, an automatic door, a phone that dims its own screen. Ask what it senses, what it decides, and what it changes.
Teach Input → Processing → Output on those examples, then extend to feedback: the fridge measures its own temperature and that measurement changes what it does next.
Draw the distinction that runs through the whole unit: an open-loop system acts without checking the result (a timer), a closed-loop system measures the result and adjusts (a thermostat). Have students sort a list of ten devices into the two categories and defend the hard ones.
Introduce block diagrams as the way engineers draw this, and have students diagram two systems from the sorted list.
Issue the design brief and read it together. Do not start solutions — the point is that students carry the brief for the rest of the semester and it gets sharper as they learn what components can do.
Set up the record of evidence and explain that it is kept as they go.

Students

Pick a device in your home you have never thought about. Work out what it senses, what it decides, and what it changes.
Sort ten devices into open-loop and closed-loop. Be ready to argue about the ones that are hard to place.
Draw block diagrams for two of them.
Read the design brief and highlight every word that constrains what you can build.
Set up your record of evidence and make your first entry.

Outcomes: VCE-SE-U1-O1

2. How electrotechnology got here, and what it costs (Identifying & defining)

Teacher

Trace one line of development in depth rather than skimming several. The silicon chip works well: valve, transistor, integrated circuit, microcontroller — with the point being that each step made systems smaller, cheaper and more numerous. Telecommunications works equally well if your students prefer it.
Land the consequence: the reason a student can afford to put a microcontroller in a school project at all is a hundred years of that development.
Move to impacts. Take one component the students will actually use and follow it: where the materials come from, how it is made, how it is shipped, what happens when it is thrown away.
Run a lifecycle comparison of two components that do the same job — an incandescent lamp against an LED, or aluminium against copper. Students collect the numbers rather than being given them.
Draw out social, environmental and economic impacts as three separate lenses, and make students say which lens they are using when they make a claim.
Connect it back to the brief: the system they build will itself have impacts, and those belong in their evaluation.

Students

Build a timeline for one line of development, annotated with what each step made possible.
Choose a single component from your kit and follow it from raw material to disposal.
Compare two components that do the same job across cost, energy, lifespan and what happens at end of life. Present the comparison as a table with your sources.
Write a short position on which you would specify and why, naming which impacts you weighted most heavily.

Outcomes: VCE-SE-U1-O1

3. Components, symbols and circuits (Researching & planning)

Teacher

Teach the schematic symbols for the components in the kit, and the habit of reading a circuit as a diagram rather than a picture of wires.
Make the point that the same circuit has several representations — schematic, breadboard layout, PCB artwork, Veroboard — and that being able to move between them is a core engineering skill. Draw one circuit all four ways.
Introduce simulation before the bench, using the Little Bird breadboard editor (or Tinkercad Circuits, or Falstad — any of them will do, but pick one and stay with it so students get fluent). Students draw the divider, predict the voltage, then build it and measure. The gap between prediction and measurement is the lesson.
Make the point that a simulator models an ideal circuit. It will not show you contact resistance, a flat battery or a misread colour band, which is exactly why we still build it.
Teach Ohm's law properly here, with series and parallel resistance, and have students calculate before they measure every single time.
Teach the multimeter as a skill in its own right: selecting the range, measuring voltage across versus current through, and why you almost never put an ammeter in parallel.
Run PRP 1 and PRP 2. Students work in pairs at the bench — one builds while the other checks the calculation, then they swap. Assign the roles rather than letting pairs settle into one builder and one watcher, and make both partners responsible for both records.
Introduce datasheets — where the numbers in these calculations come from, and why the forward voltage of a red LED is not the same as a blue one.

Students

Learn the symbols for every component in your kit.
Draw one circuit as a schematic, a breadboard layout, and a Veroboard layout.
For every circuit from now on: calculate first, build second, measure third, and record all three.
Complete PRP 1 and PRP 2.
Find the forward voltage and maximum current for two different coloured LEDs in their datasheets, and explain why they differ.

Outcomes: VCE-SE-U1-O1, VCE-SE-U1-O2

PRP 1: Voltage divider — calculate, build, measure

The voltage divider is the single most useful circuit in this unit. Every resistive sensor you use is a divider with one leg that changes.

Measure the supply first. Put the multimeter across 5V and GND. It will not read 5.00V — USB power arrives through a fuse and a cable, and both drop a little. Use the number you measured in every calculation below, not 5.00.
Calculate. Choose two resistors. Work out what the voltage at the junction should be. Write it down before you build anything.
Build it on the breadboard.
Measure it across the lower resistor.
Compare calculated against measured.
Rank the causes of the gap, largest first:
- The supply. If you used 5.00V instead of your measured value, this is most of your error on its own.
- The meter. A cheap multimeter is typically accurate to about ±0.5% of reading plus a digit or two.
- The resistors. These are 1% metal film, so two of them bound the divider ratio error at roughly ±2% worst case, and usually far less.
Now measure resistance directly. Switch the meter to ohms and measure each resistor out of circuit. How close is each to its marked value?
Repeat with three different pairs, including one where the two resistors are very different in value, and describe what that does to the output.
Then try them in parallel. Put two resistors in parallel and calculate the total using 1/Rt = 1/R1 + 1/R2. Predict, measure, compare. Note that the total is always smaller than either resistor — if your answer is bigger, you have used the series formula.

Inputs	Processing	Outputs
The board's 5V rail, fed from USB	Two resistors in series divide the supply in proportion to their values	A lower voltage at the junction, measured with a multimeter

Troubleshooting:

Reading is 0V. The lower resistor is probably not connected to ground, or the divider is built across a breadboard gap. Check the centre channel.
Reading equals the supply. The lower resistor is open or missing.
Reading drifts. A probe is not making contact. Press firmly, or use a jumper into the row.

PRP 2: Current limiting — why the LED needs a resistor

An LED is not a resistor. Connected straight across a supply it draws as much current as it can and destroys itself. The resistor is what makes it a circuit.

Find the numbers. Look up the forward voltage and maximum current for your LED colour in the datasheet.
Calculate the resistor you need to limit current to a safe value.
Build and measure the current, and compare it with your target.
Change the resistor to a much larger value and measure again. Record what happens to both current and brightness.
Compare two colours. A red and a blue LED with the same resistor draw different currents. Explain why using their forward voltages.
Calculate the power. Power is P = V x I. Work out how much power the resistor is dissipating, and how much the LED is. Compare the resistor's figure against its rating — these are quarter-watt parts, so anything approaching 0.25W is a problem.
Then calculate energy. Energy is power x time. If your LED ran continuously for a day, how much energy would it use? Do the same sum for an old 60W incandescent lamp and compare. This is the number behind every efficiency claim you will make later in the unit.

Do not skip step 1. A resistor value copied from the internet works by accident, and this unit is about not working by accident.

Inputs	Processing	Outputs
5V supply	A series resistor limits current to a value the LED can survive	An LED at a safe, chosen brightness

Troubleshooting:

LED does not light. Check polarity — the long leg is the anode. LEDs only conduct one way.
LED is very dim. The resistor is much larger than calculated. Check the colour bands.
Current reads zero. The meter is in parallel rather than in series. It must be in the current path.

4. Sensing the world (Researching & planning)

Teacher

Start from the problem: a microcontroller reads voltage, but the world produces light, heat, moisture and force. A sensor converts one to the other, and the circuit around it decides how well.
Teach the resistive divider as a sensing circuit, which is why sequence 3 came first. An LDR and a fixed resistor is the same divider, with one leg that changes.
Have students discover that the choice of fixed resistor changes the useful range of the sensor. This is the first real design decision most of them make.
Distinguish analogue from digital inputs, and introduce the ADC: a voltage becomes a number between 0 and 1023, and that number is not the physical quantity until it is calibrated.
Run PRP 3 and PRP 4.
Introduce the serial plotter as a diagnostic instrument. A graph of a sensor over time shows noise, drift and range in a way a single reading never does.
Insist on calibration against a reference. A sensor that reads "high" is not a measurement.

Students

Wire an LDR as a divider and record how the reading changes with light.
Try three different fixed resistors and work out which gives the most useful range for the conditions you care about.
Complete PRP 3 and PRP 4.
Plot one sensor over ten minutes. Describe the noise, and decide whether it matters for your project.
Calibrate one sensor against a reference instrument and write down the relationship you found.

Outcomes: VCE-SE-U1-O1, VCE-SE-U1-O2

PRP 3: Light sensing with an LDR

Your first real sensor, and the same divider from PRP 1 with one leg that changes on its own.

Wire the LDR as one leg of a divider with a fixed resistor.
Read it into the board and print the value to the serial monitor.
Record readings in three conditions: covered, room light, and a torch on it. Write the numbers down.
Change the fixed resistor to a different value and repeat all three. The readings will change.
Decide which fixed resistor gives the most useful spread for the conditions you care about, and say why. This is a design decision.
Calibrate. Using a light meter or a phone app as a reference, work out roughly what your numbers correspond to in real units.

Inputs	Processing	Outputs
Ambient light falling on the LDR	The LDR's resistance falls as light rises, changing the divider output; the ADC converts that voltage to a number 0-1023	A stream of readings on the serial monitor

Code: vce_u1_03_read_ldr.ino (https://littlebirdelectronics.com.au/code/CJGzgOatgAs)

Extension:

Characterise the LDR properly: take readings across ten light levels and plot resistance against illuminance. Is the relationship linear? Most students assume it is. It is not, and finding that out is worth more than being told.

Troubleshooting:

Reading pinned at 0 or 1023. The fixed resistor is badly matched to the LDR's range. Try a very different value.
Reading barely moves. The LDR may be shadowed by your own hand, or the fixed resistor is far too small.
Readings jump around. Normal. Average several samples before deciding anything.

PRP 4: Temperature and humidity, plotted over time

This sensor is different: it does its own conversion and hands you real units. That makes it easier to use, and it hides work you should understand is happening.

Wire and read the DHT22. Report temperature and humidity.
Plot both over ten minutes using the serial plotter. Leave it alone while it runs.
Describe what you see. How much does the reading move when nothing is happening? That is your noise floor.
Change something real — breathe on it, move it near a window — and watch the response. How long does it take to settle?
Compare with a reference thermometer and record the difference.
Decide whether this sensor is good enough for your project, and say what "good enough" means for your case.

Inputs	Processing	Outputs
Air temperature and relative humidity at the sensor	The DHT22 digitises both and sends them over a single data line; the board decodes and reports them	Two calibrated values, plotted against time

Code: vce_u1_04_read_dht22.ino (https://littlebirdelectronics.com.au/code/w62RGjjGcZ8)

Extension:

Response time matters more than accuracy for control systems. A sensor that is 2°C off but responds in one second is often more useful than one that is perfect and takes a minute. Time your sensor's response and explain which property matters for your project.

Troubleshooting:

Reads nan, or the value never changes. Almost always the sampling interval. The DHT22 needs at least 2 seconds between reads — ask it faster and it returns a stale value or nothing at all. This is the single most common fault with this sensor. Check your delay before you check anything else.
Still reads nan after that. Check the data pin and that a pull-up is present. Some modules include one; bare sensors do not.
Humidity reads 100%. Condensation on the sensor, or it is genuinely saturated. Dry it and retest.

5. Control, feedback and code (Researching & planning)

Teacher

Bring sequences 1, 3 and 4 together: the system now senses, decides and acts.
Teach the threshold decision — if and else — and immediately complicate it with the problem that makes it real: a sensor sitting near the threshold makes the output chatter on and off. Introduce hysteresis as the fix, and have students find their own chatter before you name it.
Return to open versus closed loop from sequence 1, now with hardware. Students build both and compare behaviour.
Teach driving a load: a microcontroller pin cannot power a pump directly, and the reason why is current, which they can now calculate.
Run PRP 5, PRP 6 and PRP 7.
PRP 7 is the bridge to the project: soil moisture in, pump out, threshold decided by the student and justified with data.
Emphasise that the threshold is a design decision that must be defended, not a number copied from an example.

Students

Make an output respond to a sensor crossing a threshold you choose.
Find the chattering problem, then fix it with hysteresis and show the before and after.
Build the same task open-loop and closed-loop, and describe how they behave differently when conditions change.
Complete PRP 5, PRP 6 and PRP 7.
Write down your threshold value and the evidence you used to choose it.

Outcomes: VCE-SE-U1-O2

PRP 5: Threshold control — making a decision

Now the system decides for itself.

Choose a threshold from your own recorded readings, not from an example.
Write the decision: if the reading is above the threshold do one thing, otherwise do another.
Test it by changing conditions until it switches.
Find the fault. Hold the sensor right at the threshold. The output will flicker on and off rapidly. This is chattering, and every real control system has to deal with it.
Record it happening before you fix it.
Justify your threshold in writing, referring to the readings you took.

Inputs	Processing	Outputs
A sensor reading from PRP 3 or PRP 4	An if/else comparison against a threshold the student chooses	An LED that changes state when the threshold is crossed

Code: vce_u1_05_threshold.ino (https://littlebirdelectronics.com.au/code/IBTbeWhB3DQ)

Troubleshooting:

Output never switches. Your threshold is outside the range the sensor actually produces. Check your recorded readings.
Output switches immediately and stays. The comparison may be the wrong way round.
Chattering. Expected. That is step 4, not a bug.

PRP 6: Hysteresis, and open versus closed loop

Fix the chattering you found in PRP 5, then compare the two ways a system can be controlled.

Add hysteresis. Use two thresholds with a gap between them: switch on below one value, off above a higher one.
Test at the switching point again and show the chattering has gone.
Record before and after — this comparison is strong evidence.
Build the same task open-loop: act on a fixed timer with no sensor at all.
Change the conditions and compare. The open-loop version keeps doing the same thing regardless. The closed-loop version adapts.
Write down which is appropriate for your project and why. Open-loop is not always wrong — it is simpler, cheaper and cannot be fooled by a failed sensor.

Inputs	Processing	Outputs
The same sensor, near the switching point	Two thresholds instead of one: switch on at a lower value, off at a higher value	An output that switches cleanly and stays switched

Code: vce_u1_06_hysteresis.ino (https://littlebirdelectronics.com.au/code/3lNbWXQW6x4)

Extension:

How wide should the hysteresis gap be? Too narrow and chattering returns; too wide and the system responds sluggishly. Find the smallest gap that works reliably for your sensor's noise level, and justify it with your noise-floor measurement from PRP 4.

Troubleshooting:

Still chattering. The gap is smaller than the sensor's noise. Measure the noise and make the gap wider than it.
Output sticks. The two thresholds may be the wrong way round, so the system can never switch back.

PRP 7: Automatic watering — sensing, deciding, acting

The bridge to your project: a complete system that senses a resource, decides, and acts on the physical world.

Calibrate the moisture sensor in dry soil, damp soil and saturated soil. Record all three.
Choose a threshold from those readings and justify it.
Drive the pump through the driver module. A board output pin supplies tens of milliamps; the pump wants hundreds. Wiring it straight to a pin destroys the pin, and often the board.

The driver module sits between them: the board sends a small control signal, and the module switches the pump's own supply. Three things you need to know about why it is built the way it is:

The pump's power does not come from the board. It comes from a separate supply into the module's screw terminals. The board and the pump supply must share a common ground or the control signal has no reference.
A motor is an inductor. When you switch it off, the collapsing magnetic field produces a large reverse voltage spike that will destroy an unprotected switching device. The module has flyback diodes built in to clamp it — which is exactly why you use a module rather than wiring a bare transistor.
Check the pump's current draw against the module's rating before you connect it. This module handles several amps; your pump will want far less.
1. Add hysteresis so it does not cycle at the switching point.
2. Add a maximum run time. If the sensor fails or falls out of the soil, an unlimited pump empties the reservoir onto the bench. This is a safety and reliability decision and it belongs in your record.
3. Run it for a full lesson and record what happened.
4. Measure the saving. How much water does it use compared with a fixed timer over the same period?

Inputs	Processing	Outputs
Soil moisture, measured in a tray of soil	Threshold with hysteresis, plus a maximum run time as a safety limit	A pump that runs only when the soil is genuinely dry

Code: vce_u1_07_watering.ino (https://littlebirdelectronics.com.au/code/dfl7n929dz0)

Extension:

Step 5 is the most important step in this activity and the one students skip. A control system that cannot fail safely is not finished. Ask what else could fail — sensor disconnected, pump jammed, reservoir empty — and what the system should do in each case.

Troubleshooting:

Pump does not run. Check the driver, and check the pump's supply is adequate. The board's 5V rail usually is not.
Board resets when the pump starts. The motor is browning out the supply. Power the pump separately and share only ground.
Sensor readings drift over hours. Corrosion on exposed probes. Real effect, worth recording, and a good argument for capacitive sensing.

6. Investigating and defining your own problem (Identifying & defining)

Teacher

Re-read the design brief now that students know what components can do. Most will revise what they thought they wanted to build, which is the point of the ordering.
Teach investigating and defining as an activity with outputs, not a vague research phase: a defined problem, a design brief, research into the factors that influence the system, and evaluation criteria.
Have students identify a specific resource problem with a real user. "Save water" is not a problem. "The school greenhouse is watered on a timer and floods in winter" is.
Teach the factors that influence creation and use and have students work out which ones actually bind on their project. Most projects are constrained by two or three, not all of them.
Teach design thinking strategies explicitly, as three distinct tools with different jobs, and run a short activity on each so students have used all three before they are asked to name them:
- Critical — judging what is there. Take an existing product that addresses this problem and pull it apart: what does it do well, where does it fail, what did its designer prioritise?
- Creative — generating what is not there. Rapid divergent work: twenty ideas in ten minutes, no filtering, quantity over quality.
- Speculative — asking what could be. Push the timeframe out: if water cost ten times what it does now, what would this system need to be?
Then make students name which strategy they used for each idea they keep. A student who cannot say why an idea is creative rather than critical has usually only done one of the three.
Build evaluation criteria from the constraints, considerations and system parameters. Criteria must be measurable: "works well" cannot be assessed, "keeps soil moisture between 30% and 50%" can.
This is the first assessment point.

Students

Identify a specific resource problem with a real user, and say who that user is.
Write your design brief: the problem, its context, the constraints and the considerations.
Research the factors that will influence how your system is created and used, and identify which ones actually bind on your project.
Write measurable evaluation criteria, covering both the system and your use of the process.
File all of it in your record of evidence.

Outcomes: VCE-SE-U1-O1

7. Generating and designing (Researching & planning)

Teacher

Require three genuinely different design options, not one idea drawn three ways. Different sensing approaches, different outputs, different power strategies.
Teach drawing techniques for design ideas, options and a proposed design, and insist on annotation. An unannotated sketch cannot be assessed.
Model before building. Students simulate their circuits and calculate the numbers that matter — divider voltages, LED current, power budget — for each option.
Teach feasibility honestly: an option can be rejected for time, cost, skill or available components, and saying so is good engineering rather than an admission.
Students select and justify a preferred option against their own evaluation criteria, with reference to their modelling. The justification is the assessable part, not the choice.
Second assessment point.

Students

Generate three design options that differ in approach, not just in appearance.
Annotate every drawing with components, connections and the decisions behind them.
Model and calculate each option before you commit — divider voltages, current draw, power budget.
Select your preferred option and justify it against your evaluation criteria, using your modelling as evidence.
Record why you rejected the other two.

Outcomes: VCE-SE-U1-O1, VCE-SE-U1-O2

8. Planning and managing (Researching & planning)

Teacher

Teach a work plan as a real instrument: a sequence of steps, a timeline, measurable milestones, and the materials, components, tools and processes each step needs.
Have students build a Gantt chart and then commit to milestones they can be held to. Milestones that cannot be checked are decoration.
Teach risk assessment using the hierarchy of control, applied to the tools and processes their own project actually needs. A project that is only breadboard has a different risk profile to one that involves a drill.
Teach the three kinds of document an engineer works from, and have students find one of each for their own project:
- a specification, which states what a system must achieve;
- a data sheet, which states what a component actually does — the numbers they used back in PRP 2 and PRP 4;
- a safety data sheet (SDS), which states the hazards of a substance and how to handle it, and which they need for anything they are gluing, soldering or solvent-cleaning with.
Teach project management as an iterative practice, not a plan written once. The work plan is a living document: students should expect to revise it as they learn what does not work, and the record of that revision is evidence of the process working. Adaptability and continuous refinement are what separate a real work plan from a Gantt chart drawn in week 13 and never opened again.
Have students commit to reviewing their plan at the end of each production lesson and recording what changed.
Have students produce a materials list with real prices and lead times. A component that takes three weeks to arrive changes the plan, and finding that out now rather than in week 16 is the lesson.
Make clear the work plan will change, and that recording what actually happened against what was planned is part of the assessment later.

Students

Write a work plan: steps, timeline, milestones, materials, components, tools and processes.
Draw it as a Gantt chart with milestones someone else could check.
Complete a risk assessment for the tools and processes your project needs, using the hierarchy of control.
Price your materials list and find out the lead time on anything you do not already have.
Keep the original plan. You will compare it to what actually happened.

Outcomes: VCE-SE-U1-O2

9. Producing and implementing (Producing & implementing)

Teacher

Production runs for three weeks. Expect the plan to survive about one of them.
Insist on subsystem testing before integration. Students who wire everything and then power it up cannot find the fault. Sensor working, then output working, then the decision between them.
Teach troubleshooting as a method, not as luck: what did you expect, what did you measure, where do they diverge, what is the smallest thing you can change to test one hypothesis.
Enforce OHS compliance for the tools each student is using, against the risk assessment they wrote in sequence 8.
Require progressive documentation: photographs of the version that did not work, the measurement that prompted a change, the modification and why. Ten minutes at the end of each lesson, alongside the work plan review.
Run a weekly design review in small groups: each student explains their current problem to three others and takes suggestions. It costs fifteen minutes and it is the most reliable way to unstick a student who has been quietly failing at the same thing for a fortnight. Students record whose suggestion they took, which is both good practice and useful evidence.
Watch for the students who quietly abandon their design and copy a PRP. Redirect early — a smaller original project is worth more than a copied larger one.

Students

Follow your work plan, and record where you depart from it and why.
Test each subsystem on its own before you connect them together.
When something does not work: state what you expected, measure what is actually happening, and change one thing at a time.
Photograph the failures as well as the successes.
Record every modification and repair, with the reason.

Outcomes: VCE-SE-U1-O2

10. Diagnostic testing and evaluation (Testing & evaluating)

Teacher

Separate does it work from how well does it work. The second needs data.
Teach diagnostic testing as designed procedure: state the purpose, the expected result and why, the method and equipment, then the actual result and the discrepancy. A test without an expected result is just fiddling.
Have students design tests that produce numbers over a range, not a single pass or fail. Sensor response across conditions, output behaviour either side of the threshold, current draw under load.
Require comparison against the datasheet or against theory, and an explanation of any discrepancy. Discrepancies are findings, not failures.
Evaluate the system against the evaluation criteria written in sequence 6, and the process separately: where the work plan held, where it did not, what they would do differently.
Require proposed improvements with reasons, which is where the strongest students separate themselves.
Third assessment point.

Students

Design tests that produce data across a range, not a single yes or no.
For each test: purpose, expected result and why, method and equipment, actual result, and any discrepancy.
Compare your results to the datasheet or to theory and explain the differences.
Evaluate your system against the criteria you wrote, using your test data as evidence.
Evaluate your use of the process: what worked, what did not, what you would do differently.
Propose improvements to the system and to how you worked, with reasons.

Outcomes: VCE-SE-U1-O2

Glossary

Actuator	A component that turns an electrical signal into a physical action — a motor, a pump, a solenoid.
Analogue to digital converter (ADC)	The part of a microcontroller that turns a voltage into a number. On these boards, 0-5V becomes 0-1023.
Block diagram	A drawing of a system as labelled boxes and arrows, showing what flows where without showing how any box works inside.
Calibration	Working out what a sensor's raw readings correspond to in real units, by comparing against a trusted reference.
Capacitance	A component's ability to store charge, measured in farads. Capacitors in parallel add (Ct = C1 + C2); in series they combine like parallel resistors (1/Ct = 1/C1 + 1/C2).
Closed-loop control	Control that measures the result of its own action and adjusts. A thermostat.
Current	The rate of flow of charge, measured in amps. Measured by putting the meter in series, in the path the current takes.
Design brief	A statement of the problem, its context, constraints and considerations. It defines what must be achieved without specifying the solution.
Energy	Power multiplied by time. The number behind any claim that a system saves resources, because a saving is only meaningful over a period.
Evaluation criteria	Measurable statements, written before building, used to judge whether the finished system does what the brief required.
Feedback	Information about a system's output being fed back to influence its input. What makes closed-loop control possible.
Forward voltage	The voltage dropped across an LED when it conducts. Different for each colour, and the reason a resistor calculation needs the datasheet.
Hierarchy of control	The ordered set of ways to manage a risk, most effective first. Four steps: 1) eliminate the hazard; 2) reduce the risk, by substituting something less hazardous, isolating people from it, or making an engineering change; 3) administrative controls such as procedures and training; 4) personal protective equipment. PPE is last because it protects one person and only while worn.
Hysteresis	Using two thresholds instead of one, with a gap between them, so an output switches cleanly instead of chattering.
Input	Anything a system senses or receives from its environment.
Milestone	A checkable point in a work plan. If nobody else could confirm it has been reached, it is not a milestone.
Ohm's law	Voltage equals current times resistance (V = I x R). Rearranged, it gives any one of the three from the other two, and it underlies every calculation in this unit.
Open-loop control	Control that acts without measuring the result. A timer.
Output	Anything a system does to its environment as a result of processing.
Parallel circuit	Components connected across the same two points, so each sees the same voltage. Resistors in parallel combine as 1/Rt = 1/R1 + 1/R2, and the total is always less than the smallest one.
Parameter	A measurable property of a system that can be set or optimised — a threshold, a flow rate, a response time.
Power	The rate at which energy is used, measured in watts. P = V x I. A quarter-watt resistor asked to dissipate more than 0.25W will overheat.
Record of evidence	The progressive, multi-modal record of the design process: sketches, photographs, test data, decisions and the reasons for them.
Resistance	Opposition to current flow, measured in ohms. Measure it with the component out of circuit — in circuit, the rest of the board reads in parallel with it and the answer is wrong.
Risk assessment	Identifying what could cause harm in a process, and deciding what to do about it before starting.
Schematic	A circuit drawn with standard symbols, showing electrical connections rather than physical layout.
Sensor	A component that converts a physical quantity into an electrical signal.
Series circuit	Components connected end to end, so the same current flows through each. Resistors in series add: Rt = R1 + R2.
Systems engineering process	The process used throughout this study: investigating and defining, generating and designing, producing and implementing, evaluating, and planning and managing.
Tolerance	How far a component's real value may differ from its marked value. The 1% metal film resistors in this kit, marked 1000Ω, will measure between 990Ω and 1010Ω. Tolerance is usually a smaller source of error than the supply voltage you assumed.
Voltage divider	Two resistances in series across a supply, producing a lower voltage at their junction. The basis of most resistive sensing.
Work plan	The sequence of steps, timeline, milestones, materials, components, tools and processes needed to produce a system.

Bill of materials

Role	Product	SKU	Qty / student	Qty / class of 30	Price
Core	Uno R3 - Little Bird	LB-00300	1	30	$19.55
Core	Breadboard - Full-Size (Bare)	SF-PRT-12615	1	30	$15.65
Core	3 Colour Male to Male Jumper Wire 20cm x 30	LB-PT-JUMPER-KIT	1	30	$5.85
Core	Resistor Kit in Plastic Case	LB-LR0679	1	30	$15.45
Consumable	5mm LED Mixed Pack (50 pcs)	LB-50LED	1	30	$5.80
Core	LDR Photoresistor	LB-LR0282	2	60	$1.25
Core	DHT22 module with cable	LB-LR0102	1	30	$10.25
Core	Soil Moisture Sensor	LB-LR0040	1	30	$3.50
Shared classroom	Jumper Wires Premium 6 M/F Pack of 100	SF-PRT-09139	0	1	$55.65
Shared classroom	LCD Digital Multimeter	LB-00206	0	8	$52.75
Shared classroom	L298N Dual H-Bridge Motor Driver Board	LB-OWL-HBRIDGE	0	8	$15.45
Shared classroom	DC Diaphragm Pumps for Arduino Automatic Smart Plant Watering Kit	LB-PMMA19004A001	0	8	$9.75
Shared classroom	Digital Vernier Callipers - 150mm, Four-Way Measurement	LB-HR0309-27	0	4	$14.20
Extension	Thermoelectric Generator (TEG) Module - SP1848-27145, 40 x 40mm	LB-HR0214-42A	0	1	$11.42
Extension	Flex Sensor - 2.2 inch	LB-HS7762	0	1	$25.30

Add the core kit to your cart at https://littlebirdelectronics.com.au/curriculum/vce-systems-engineering-unit-1