States & Transistions
This week your primary focus for the workshop should be on your project and your specific needs and requirements.
The theme for the week is intended as supporting material for the development of your final product. One of the key elements of the lecture was implementing finite state machines.
Finite State Machines
One of the key areas where realtime applications fall down whether it’s a computer game or an automous robot is handling the concurrent states and transitions. It’s vital to identify different states in the system:
- Button ON
- Button OFF
- Character IDLE
- Motor FORWARD
- Motor REVERSE
- Led BLINKING
- Audio PLAYING
- Enemy IN RANGE
There are numerous states in a system and often these are monitored in relatively naive ways. Using an if statement or a switch case nested in an update or a loop. We may still deploy these to detect thresholds but nonetheless we can use more advanced programming techniques to manage and transition effectively avoiding ambiguity, memory leaks and continuous calibration.
Suggested Tasks
- Identify what the states in your system? Pay specific attention to the hardware/embedded software aspect. Have a method to measure when LED’s are on or off, for example
- Develop a state diagram to describe them and the transitions associated with them
- Consider refactoring your code around the state design pattern. The State pattern suggests that you create new classes for all possible states of an object and extract all state-specific behaviors into these classes.
Supporting Materials
Refactoring Guru - State Design Pattern
https://refactoring.guru/design-patterns/state
Arduino State Pattern Example Repo
https://www.tinkercad.com/things/iK5nt1hK1a1-state-machine-v2/editel?sharecode=1rTt9kOGr6jWJCP3FerWqFwGnoi-TieRCMLcAtDSPO0