This repository documents the design, development, and simulation of a synchronous sequential machine to control a motorized wheelchair based on stakeholder requirements. The project emphasizes user-friendly design, safety, compactness, and minimal use of logic gates.
The project was undertaken as part of coursework in Spring 2022. The objective was to design a finite state machine to control the motion of a wheelchair. The design considers inputs from a joystick to determine motor directions while incorporating safety and functional requirements.
- Joystick Control: Implements joystick-based input for intuitive forward, backward, left, and right movement.
- Safety Mechanisms: Includes features such as error indicators for invalid joystick inputs.
- LED Indicators: Displays movement status and error signals.
- Compact Design: Optimized state transitions with minimal logic gates.
- User-Centric Design: Designed with stakeholder feedback to ensure ease of use and practical functionality.
- Identified user needs, including lightweight design, safety straps, and joystick controls.
- Incorporated feedback into the machine's design criteria.
- Designed states for movement (e.g., center, first left, first right, etc.).
- Developed a state definition table:
| State | Binary | Description |
|---|---|---|
| S0 | 000 | Center |
| S1 | 001 | First Left |
| S2 | 010 | Second Left |
| S3 | 011 | Third Left |
| S4 | 100 | First Right |
| S5 | 110 | Second Right |
| S6 | 111 | Third Right |
- Developed multiple designs and evaluated them using criteria such as:
- Minimal gates (15%)
- Safety (30%)
- Compactness (20%)
- User-friendliness (30%)
- Chose the best design based on the weighted evaluation.
- Simulated the winning design using Digital simulation software.
- Verified state transitions, outputs, and functionality through rigorous testing.
The following equations were implemented to achieve the desired state transitions:
- Q2:
Q1Y’ + Q1’X’ + Q0X’ + QZQ0X + Q1’Q0’XY + Q2’QZ’Q0XY - Q1:
Q0’X’Q2 + Q2’Q1’Q0X + Q2’Q1Q0’Y’ + Q2’Q1Q0X’ + Q2Q1Q0Y’ + Q2Q1’Q0’Y - Q0:
Q0X’Y’ + Q0XY + Q0’X’Y + Q0XY’
The circuit was tested under various scenarios to ensure proper functionality. Testing included:
- Validating joystick input handling.
- Checking expected vs. actual outputs.
- Ensuring the error indicator activated for invalid inputs.
A demonstration video of the final design is available:
- Design Documentation: Includes state diagrams, Karnaugh maps, and transition tables.
- Simulation Files: Digital simulation files for the winning design.
- Test Results: Testing plans and results for the circuit.
This project demonstrates the successful implementation of a synchronous sequential machine tailored to stakeholder needs. The design balances technological, societal, and environmental considerations, ensuring practicality and reliability.