Ev3 Programming 2.5 - How to create my block with input and output

Welcome to Blue Angels Robotics, my name is Emma. In this video, you are going to learn how to create My Block with input and output. Let’s take a look why we need My Blocks. First, My Block makes common code reusable. If your robot needs to repeat an action again and again, it’s time to create My Blocks. Second, it makes code changes quickly in a single place. Third, My Block helps organize your code. When your program grows larger, it becomes difficult to track the logic. However, if you group the code logically into My Block, the code will become easy to understand. Also, My Block makes debug easy, you can run each of the My Block by itself. Last but not least, using My Block saves memory. Now, let’s create a My Block from the sample program that we created in video 2.4: How to convert centimeter to degree for moving distance. This sample program converts centimeter value to degree value. The first constant block has the centimeter value. The value transfers to the next Math block as the input value through data wire. The math block converts the centimeter value to degree value and output it through data wire to the next Moving Steering block. Now, let’s create the centimeter to degree My Block. Highlight all the blocks you need for the My Block. For this sample program, only the Math block is needed. Don’t highlight the constant block. Click “Tools” Menu, and select “My Block Builder”. In the “My Block Builder” dialog, give this My Block a name “cm2Degree”, Put a description, such as “This my block converts centimeter to degree, wheel diameter 4.32 cm”. Then, select a My Block icon. I can pick up an existing icon, or you can create your own icon. I have created the cm2Degree icon, and I select this icon. Now, click the “Parameter Setup” tab to setup the input and output parameters. You can edit existing parameter or add a new parameter. Because we have input and output data wire connected to the highlighted My Block code, the My Block builder automatically created 1 input and 1 output parameter. The first parameter is “Number Input”, give it an appropriate name, such “input_cm”. You can set a default value, such as 0, select a parameter style. You can also click the “Parameter Icons” tab to select an icon for this input parameter, for example, select the cm icon. Now, let’s configure the output parameter. Click the second parameter “Number Output”. Give it a name, such as “output_degree”. The rest of the default values are correct for this output parameter. Go to “Parameter Icons” tab to find an icon for the output parameter, for example, this one. Click “Finish” button to create “cm2Degree” My Block. You will find that the math block will be replaced by the cm2Degree My Block. Click “My Block” palette, there will be a new My Block named “cm2Degree” that shows up. If you want to see the code of My Block, just double click the My Block. You can use this My Block in your code, as the way you use other EV3 blocks. For example, in this new program, drag and drop a cm2Degree Myblock and a Moving Steering block to the programming canvas. Set the Moving Steering block “On for degree”. Now, you can decide how many centimeters to run. For example, I can input 10 in it, and then data wire the output degree value to the Moving Steering block. When I run this program, my robot run 10 centimeters and then stop.