- Difficulty
- Beginner
- Build time
- 35-60 min
- Estimated cost
- $0-$8
- Age range
- 10-16
- Workspace
- A clear table about 90 cm wide
The finish line
What you will build
A sealed steel token completes the maze in under 90 seconds without leaving the track or exposing a loose magnet.
Learning goals
- Identify how hand motion of an enclosed magnet below the board produces controlled steel-token motion through the maze.
- Construct and explain a remote hand translation-to-token translation system.
- Measure how board-to-controller gap changes performance.
- Diagnose losses caused by board thickness and surface friction.
Before you build
Materials, tools, and safety
Reuse-material cost: $0-$3 with reused materials. Supervision: Adult help recommended for sharp or heated tools.
Tools
- Ruler
- Pencil
- Scissors
- Masking tape
Low-cost swaps
- Use clean recycled packaging whenever it has similar stiffness.
- Substitute paper clips, binder clips, or twist ties for specialty fasteners.
- Use a magnetic whiteboard eraser as the enclosed controller and a large steel jar lid as the token.
Project-specific safety
- Wear eye protection when stretched elastic, magnets, or spinning parts are present.
- Test at floor or tabletop height and keep the path clear of people.
- Magnets can cause severe injury if swallowed; use only large, fully enclosed magnets under adult control and keep them away from medical devices and electronics.
Orient the build
Place the build so hand motion of an enclosed magnet below the board is on your left and controlled steel-token motion through the maze is on your right. Call the side facing you the front, the far side the back, the tabletop the bottom, and the opposite face the top.
Build it
Step-by-step instructions
Step 1
Plan the route
Draw one continuous 5 cm-wide path with a start, three turns, and finish.
Avoid narrow dead ends.
Step 2
Build the walls
Tape strips along both path edges and test token clearance.
Round inside corners to prevent trapping.
Step 3
Seal the token
Sandwich the steel washer between two card disks and tape every edge.
Make it too large to swallow.
Builder checkpoint: After seal the token, the first subassembly should stay aligned when handled gently.
Step 4
Enclose the controller
Seal the magnet inside a card pouch attached to a broad handle.
Inspect all seams before use.
Watch for: If this stage binds or drifts, inspect wall impacts before adding more parts.
Step 5
Add the top cover
Tape clear plastic over the wall tops with no token-sized gaps.
Leave one adult-access flap secured by tape.
Step 6
Calibrate the gap
Move the controller beneath the start and confirm the token follows.
Add a thin spacer if attraction is too abrupt.
Builder checkpoint: After calibrate the gap, operate the build slowly and confirm that controlled steel-token motion through the maze begins without binding.
Step 7
Run a baseline maze
Time one slow completion without lifting or shaking the board.
Record where control is lost.
Step 8
Tune the challenge
Change one turn radius or add one nonmagnetic obstacle.
Repeat three timed trials.
Builder checkpoint: At the final checkpoint, A sealed steel token completes the maze in under 90 seconds without leaving the track or exposing a loose magnet.
See the engineering
Why it works
- Input
- hand motion of an enclosed magnet below the board
- Output
- controlled steel-token motion through the maze
- Motion
- remote hand translation-to-token translation
- Energy losses
- board thickness, surface friction, magnet offset, wall impacts
Why this works
Magnetic force through materials
A magnet attracts ferromagnetic steel through thin nonmagnetic cardboard. The force becomes weaker as the gap increases, so board thickness and token mass matter.
Look for: Stack paper under the token and find the greatest gap at which the controller still starts it moving.
Where the energy goes
Efficiency and losses
The ideal model leaves out board thickness, surface friction, magnet offset, wall impacts. These effects turn some input energy into heat, sound, vibration, or unwanted motion, so measured performance will be lower than an ideal calculation.
Look for: Run the build slowly and locate the first place where board thickness becomes visible or audible.
Math bite
Measure completion improvement
Formula: percent improvement = (first time - new time) / first time × 100%
- First time = 80 s
- New time = 60 s
Substitute: improvement = (80 - 60) / 80 × 100% = 25%
Result: The new run is 25 percent faster.
Practice and design changes both affect time.
Timing reaction adds small uncertainty.
Make it behave
Test, troubleshoot, and tune
Controlled test
Start here: Confirm the token follows over a straight 20 cm path before using the maze.
Success looks like: The enclosed token reaches the finish in under 90 seconds during three trials.
Measure: Completion time, wall contacts, and control losses.
Change: board-to-controller gap
Keep constant: maze, token, magnet, operator, and start method
- no spacer
- one card spacer
- two card spacers
| Symptom | Likely cause | Confirm it | Fix |
|---|---|---|---|
| The token will not start | Gap is too large or token is not steel | Test attraction with the board open | Use a thinner board or verified steel washer |
| The token jumps over walls | Attraction is too abrupt | Move the controller slowly at a corner | Add a spacer or taller walls |
| It sticks at corners | Wall radius is tight or surface rough | Push the token manually | Round corners and smooth tape |
| The controller detaches | Pouch seam or handle is weak | Inspect before every run | Stop and reseal with a larger pouch |
Choose your tradeoff
The best maze balances reliable attraction with enough friction and distance to require control. Stronger is not always better; a small spacer often makes movement smoother.
Keep experimenting
Try another version
Wide-route maze
Use two turns and 7 cm paths.
Precision course
Add numbered checkpoints and count wall contacts.
Field mapping
Measure the maximum pickup gap at several controller offsets.
Build together
Classroom and access options
Classroom version
Teams can compare board-to-controller gap while keeping maze, token, magnet, operator, and start method. Assign builder, tester, recorder, and explainer roles; have each team predict the result before collecting three trials.
Access adaptations
- Offer pre-cut parts and tactile or high-contrast measurement marks.
- Split roles so one builder can hold, another assemble, and another measure.
- Make paths at least 5 cm wide, add raised tactile wall labels, and attach the controller to a large handle.
Reflect on the design
- How did board-to-controller gap change the measured result?
- Where did board thickness affect the build most strongly?
- What evidence shows that magnetic force through materials explains the motion?
- Which change would improve controlled steel-token motion through the maze without creating a new problem?
Glossary
- Magnetic force through materials
- A magnet attracts ferromagnetic steel through thin nonmagnetic cardboard.
- Input
- The action or energy supplied to a system; here it is hand motion of an enclosed magnet below the board.
- Output
- The useful response produced by a system; here it is controlled steel-token motion through the maze.
- Efficiency
- The fraction of input energy that becomes useful output instead of friction, sound, heat, or unwanted motion.
Build your dreams
One build can start the next.
Share what you learned, change one variable, and help another builder understand what worked.
Explore more guidesSources and build notes
A familiar household engineering activity implemented with original instructions and controlled tests.
- Classroom engineering basis: A common educational challenge implemented with original dimensions, tests, diagrams, and instructions.
Written and edited by BrickLabClips. Published 2026-07-22; updated 2026-07-22.