Goal
The position or result the system is trying to reach.
Topic Guide
Feedback
In a feedback loop, a system checks the result of an action before deciding what to do next.
Why this matters
A robot turns, reads the sensor again, and decides whether the correction helped. A game can check position after movement and return a player who has crossed the boundary.
Beyond this topic
A cyclist looks ahead and makes many small steering corrections. A robot patrol uses sensor readings instead of eyesight, but it also has to check what happened after each turn.
Math and logic
Observation
A measurement of the current result.
Difference
The gap between the measurement and the goal.
Correction
An action chosen to reduce the gap.
Small examples
Boundary correction
Return a sprite after its coordinates leave the allowed area.
Line following
Adjust the steering after each surface reading.
Speed control
Compare the measured speed with a target and change the motor command.
Visible game state
Use sound or text to show whether a rule has fired.
Program connections
Where this topic appears.
Active now
Robotics
Students write commands, wire simple circuits, read sensors, and trace physical cause and effect through the Sense–Decide–Act loop.
Active now
Scratch & Game Design
Students author games, animations, simulations, and strange interactive stories while learning how events, rules, and state fit together.
Coming later
AI & Smart Machines
A possible later program for testing patterns, predictions, prompts, mistakes, and the limits of AI tools.
Common mistakes
No second measurement
The system keeps correcting without checking whether the first change helped.
Correction too large
The result overshoots the goal and swings back the other way.
Slow feedback
The new reading arrives too late to guide the next action.
Unclear goal
There is no target value against which to judge the result.
Put the idea to work
Robotics
Computer Lab Project
Robot Patrol Challenge
Design a repeating patrol that notices an obstacle, tries a response, and checks whether the response worked.
See how it works
Robotics
Guided Project
micro:bit Reaction Timer
Build a reaction timer with a random delay, an early-press rule, and results in the correct units.
See how it works
Scratch & Game Design
Guided Project
The Floor Is Definitely Lava
Build a one-room platform game with a controlled jump, safe platforms, lava, and a clean restart.
See how it works