Control and sequencing

 Control and sequencing is used in all areas of computing including robotics and video games. We build flowcharts and algorithms to form the basis of all software programs.


Control technology

Control technology is used to:

  • operate systems, eg traffic lights
  • control actions, eg a robot’s movement
  • create video games
  • control manufacturing devices, eg laser cutters

Computers follow instructions or sequences programmed into them. A flowchart can be used to help design a sequence. Actions can be ordered, reordered or removed if no longer necessary.

Robot being programmed to move

Advantages of computer control systems

  • Computers do not need breaks.
  • Computers can repeat actions in an identical way indefinitely.
  • Computers can work in environments that are dangerous for people.

Disadvantages of computer control systems

  • A computer is only as good as its programming ,which may contain errors.
  • If a computer is underpowered it might take too long to do something in a time-critical situation.
  • A computer faced with conditions not covered in its programming will not know what to do.

Control systems within the home

There are many items within our homes that use control systems. These include:

  • electric kettles
  • washing machines
  • TV remotes
  • TV recording devices
  • security lights
  • robotic vacuum cleaners

Robotics is a growing and developing field made possible by control. The abilities of robots will improve with the development of better sequences and technology.

One area where robotics plays an important role is in the unmanned exploration of distant planets.

CAD or CAM

Computer aided design (CAD) or computer aided manufacture (CAM) is using computers to design products in either 2D or 3D. They are then manufactured.

3D printers and laser cutters are examples of CAD or CAM in action.


Flowcharts and sequencing

Software can be used to create sequences in a flowchart, to view onscreen simulations. Examples include:

  • Flowol
  • Logicator
  • Crocodile Clips

Symbols linked together form a flowchart. Flowchart programming consists of:

  • sequences of instructions that lead to a real-life simulation
  • decisions that result in two different actions
  • loops that repeat an action until a certain condition is met
  • variables that store data for use in decision making

Basic flowchart symbols

Basic flowchart symbols showing terminator, input/output, process, decision and line tool and their uses

Visual programming, or programming with a flowchart, can be used to focus on the logic of the solution without getting distracted by the complexity of a written programming language.

Control and sequencing flowchart

Video games

Games are based on complex sequencing and programming. Depending on what the player decides, the game changes. The more complex the sequencing and programming, the more choices the player has.

Examples of software that can be used to create games include:

  • Adobe Flash
  • Scratch
  • Alice
  • MissionMaker

Scratch

A typical game in Scratch consists of a script, or a list of commands, that make an object behave in a certain way. It uses its own flowchart programming language to create interactive stories, animations, games, music and art.

MissionMaker

MissionMaker creates 3D worlds and people. It uses sequences that act as rules for gameplay.