**Course Title:** MATLAB Programming: Applications in Engineering, Data Science, and Simulation **Section Title:** Application Development with MATLAB **Topic:** Develop a simple interactive GUI application using MATLAB's App Designer.(Lab topic) In this lab topic, we will explore the basics of MATLAB's App Designer and develop a simple interactive GUI application. By the end of this topic, you will be able to design, create, and deploy a GUI application using App Designer. **What is App Designer?** App Designer is a graphical user interface development tool in MATLAB that allows you to design, create, and deploy GUI applications. It provides a visual interface for creating and arranging GUI components, such as buttons, sliders, and plots, without writing extensive code. **Getting Started with App Designer** To access App Designer, navigate to the MATLAB toolstrip and click on the "Apps" tab. In the "Apps" tab, click on "App Designer". Alternatively, you can type `appdesigner` in the MATLAB command prompt to open App Designer. **Designing the GUI Application** For this lab topic, we will create a simple GUI application that simulates a thermostat. The application will have the following components: 1. A slider to set the desired temperature 2. A button to start the thermostat 3. A plot to display the temperature over time To create this application, follow these steps: 1. Open App Designer and choose a blank app template. 2. Drag and drop a slider component onto the app canvas. Set the slider properties to "Value" and "Tag" to "temperature_slider". 3. Drag and drop a button component onto the app canvas. Set the button properties to "Text" and "Tag" to "start_button". 4. Drag and drop an axes component onto the app canvas. Set the axes properties to "Tag" to "temperature_plot". **Writing Code for the GUI Application** Once we have designed the GUI application, we need to write code to define its behavior. App Designer provides a code view where we can write MATLAB code to interact with the GUI components. In this example, we will write code to: 1. Update the temperature plot when the thermostat is started 2. Start the thermostat when the button is clicked To write code for the GUI application, follow these steps: 1. In the App Designer code view, create a callback function for the start button. 2. In the callback function, use the `get` function to retrieve the temperature value from the slider. 3. Use the retrieved temperature value to update the temperature plot. ```matlab % Start button callback function function startButtonPushed(app, event) % Retrieve temperature value from slider temperature = app.temperature_slider.Value; % Update temperature plot plot(app.temperature_plot, temperature); end ``` **Deploying the GUI Application** Once we have designed and coded the GUI application, we can deploy it as a standalone executable file. To deploy the GUI application, follow these steps: 1. In the App Designer, navigate to the "File" menu and select "Save and share" > "Export" > "Standalone executable". 2. Choose the desired platform and click "OK" to export the app. **External Resources** For more information on MATLAB's App Designer and GUI development, visit: * MATLAB Documentation: [Creating Apps in App Designer](https://www.mathworks.com/help/matlab/creating_guis/app-designer.html) * MATLAB Documentation: [Sharing and Deploying Apps](https://www.mathworks.com/help/matlab/sharing-and-deploying.html) **Conclusion** In this lab topic, we explored the basics of MATLAB's App Designer and developed a simple interactive GUI application. By designing, creating, and deploying a GUI application, you gained hands-on experience with App Designer. If you have any questions or need help with this topic, please feel free to ask in the comments below.