A bench of their own, every week

Every robot starts with one bolt.

The idea. The robot does exactly what you say, in exactly that order — nothing more, nothing less.

On the bench. Their first drive bot — chassis, two motors, wheels — assembled and taken apart with their own tools.

• Read a program top to bottom and say what the robot will do before it moves
• Drive a taped course by writing, watching and adjusting the steps
• Find the wrong step and fix it instead of starting over
• Name the parts of the bot and put them back where they go

Badge testDrives a course they have not seen, then explains one mistake they fixed on the way.

Round and round — that is the whole idea.

The idea. Anything you would write twice, you write once and repeat.

On the bench. Gear trains on the drive — swap ratios and feel speed against strength — and a light strip to pattern.

• Replace a pasted-out sequence with a loop that does the same thing
• Drive a square, then a hexagon, by changing one number
• Use a forever loop for a patrol that never stops
• Explain why a bigger gear on the wheel is slower but stronger

Badge testDrives a hexagon with a six-times loop, then turns it into an octagon by changing a single number.

Sense first. Then decide.

The idea. The robot decides for itself — if this, then that — and it must know what to do otherwise.

On the bench. A distance sensor and a colour sensor, mounted, wired and calibrated on their own bot.

• Read a live sensor value and say what it means
• Write obstacle avoidance and a basic line follower
• Explain why “else” matters — what happens when nothing is seen
• Combine two conditions with and, or, not

Badge testThe robot completes an obstacle course it has never seen while the child narrates each decision it makes.

It holds something, and the something changes.

The idea. The robot remembers — a value with a name, changing while the program runs.

On the bench. A display on the bot and encoders so it can count its own wheel turns; a robot game with a goal counter.

• Count things — laps, hits, seconds — in a variable and show them
• Calibrate a sensor and store the threshold under a name, not as a magic number
• Tune a line follower with speed variables instead of rewriting the code
• Trace a variable’s value step by step on paper and get it right

Badge testBuilds a robot game whose score rises and falls on the display and ends at a target — and predicts the final score on paper before running it.

Build it once. Wire it in anywhere.

The idea. Name a chunk of work once and call it by name — with inputs, so one piece does many jobs.

On the bench. Their own circuit module — button, LED, buzzer on a board — plugged into the bot as a physical reusable block; the first servo.

• Split a long program into named functions that read like a story
• Write drive(distance) and turn(degrees) with parameters and use them everywhere
• Explain why fixing a function fixes every place it is used
• Build a working circuit and describe where the current goes

Badge testSolves a new course using only their own function library — then hands the library to a classmate, who uses it unchanged.

Many positions, one name.

The idea. Many values under one name — recorded, replayed, searched.

On the bench. A gripper arm on two or three servos; record-and-replay of arm positions; sensor logging across a run.

• Record a motion as a list of positions and replay it
• Log sensor readings across a run and find the highest and lowest
• Drive a route from a list of waypoints and change the route by editing the list
• Explain counting from zero and the off-by-one mistake

Badge testTeaches the arm a pick-and-place by hand, replays it three times reliably, then moves the drop point by editing the list — no re-recording.

The same brain, in its real language.

The idea. The same ideas, typed. The syntax has to be exact — and the error message is the clue, not the enemy.

On the bench. The same bot, now programmed in Python.

• Rewrite their Circuit-level function library in Python
• Read an error message and go to the line it points at
• Type the common symbols without hunting for them
• Explain one concept two ways — in blocks and in text

Badge testPorts their Arm project to Python so it runs identically, then fixes three planted bugs using only the error messages.

Things that talk to each other.

The idea. A thing with its own state and its own actions — and many of them, alive at once.

On the bench. Two bots talking over radio; each subsystem of the robot written as an object.

• Write a class with attributes and methods, and create two instances that behave differently
• Explain class versus object using something from the lab
• Rebuild their Python project as classes
• Send a message from one robot to another and act on it

Badge testOne class, two robots — follow-the-leader or a relay — and the child explains what the two share and what each keeps to itself.

Where every system meets.

The idea. Design how the parts fit before building — so a bigger machine does not collapse under its own code.

On the bench. A mission robot — drive, arm, sensors, display — at competition scale, built by a team of three with divided modules.

• Draw the class and state diagram before writing code
• Specialise a base robot with inheritance; compose it from parts
• Build a state machine that recovers when things go wrong — lost line, search, resume
• Integrate their module with two teammates’ and explain one design trade-off

Badge testLeads a three-stage team mission: their module integrates with two others’, the robot completes it, and they present the design diagram.

It learns.

The idea. Instead of writing the rule, you show examples — and then you have to prove it really learned.

On the bench. A camera on the bot; a classifier trained on the child’s own labelled data; a capstone invention of their own design.

• Collect and label a training set and explain why variety matters
• Train a classifier and measure its accuracy honestly
• Wire the model’s answer to a robot action
• Fix a wrong prediction with data, not code — and say why

Badge testCapstone Show: an original robot that uses something it learned, demonstrated to the room, with a one-page “how it works” in the child’s own words. Minds mentor at Badge Days.