Topic 13 Programming basics
KS3 Computing · A program stores information in variables, works on it with operators, and controls the order with sequence, selection and iteration. Examples are in Python, with Scratch alongside for Year 7.
Topic 11 Algorithms
KS3 Computing · An algorithm is a precise, step-by-step plan to solve a problem. Computational thinking turns a messy problem into one. Every algorithm is built from just three things: sequence, selection and iteration.
Computational Thinking Computer SystemsCambridge Lower Secondary Computing 0860
Say each word, then read what it means. Every one is in the glossary too.
Read it here, or open the study page below to go one step at a time with things to try.
A brief is a short description of a problem and who has it. Good devices start with the user, not the parts.
Brief: a crossing outside the school. Users: pupils on foot, and drivers. It must never let cars go while people are crossing.
Think about every user. A person who cannot see well needs a sound as well as a light.
A sensor is an input part that measures something, like light or temperature.
An actuator is an output part that acts on the world: a light, a buzzer or a motor.
| Part of the system | Crossing example |
|---|---|
| Input | A push button for people who want to cross |
| Process | The program decides when to change the lights |
| Output | Red, amber and green lights for the cars |
| Storage | A count of how many times people crossed |
An embedded system is a computer with one job. Your device is one.
Write the steps in plain words before any code. Add the time for each step.
start: green for cars
forever:
if the button is pressed:
amber for 2 seconds
red for 5 seconds (people cross)
red and amber for 1 second
green for carsYou can draw the same plan as a flowchart. The 'button pressed?' question is a diamond.
Why plan on paper?
Changing a plan takes a minute. Changing wires and code can take a lesson. A plan also shows what to test later.
| Part | How many | Its job |
|---|---|---|
| Arduino Uno R3 | 1 | Runs the program |
| Breadboard Small | 1 | Holds the circuit together |
| LED: red, yellow, green | 3 | The traffic lights (yellow plays amber) |
| Resistor, 220 Ω | 3 | One for each LED, to limit the current |
| Pushbutton | 1 | The crossing button |
| Resistor, 10 kΩ | 1 | Pull-down: keeps the button pin at 0 until it is pressed |
Every LED needs its own resistor. Every button input needs a pull-down resistor.
Brief: a door alarm for a younger brother's bedroom. Plan it before you build.
Open the study page and go one step at a time.
A program stores information in variables, works on it with operators, and controls the order with sequence, selection and iteration. Examples are in Python.
Topic 11 · Year 7An algorithm is a precise, step-by-step plan to solve a problem. Computational thinking turns a messy problem into one.
One question at a time. The reason shows after each answer.