How To Build Liam’s Lego WeDo Windmill

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Here’s a fun new Lego WeDo 2.0 project to try – a windmill!

The idea for this came from the LittleBits Flower that Liam built a couple of weeks ago, and works in the same way. The difference here is that it’s all one system. As a result, we’ve been able to put together a full set of instructions for you. Keeping reading to get the link for these.

What is Lego WeDo?

Lego WeDo 2.0 is Lego’s entry-level robotics & coding kit, designed for the education space. The core kit comes with a smarthub, motor, tilt sensor and motion sensor, plus a range of gears, wheels, axles and bricks to create a wide range of projects. As you would expect, it’s compatible with all the standard Lego and Technic components.

Alongside the kit comes the Lego WeDo 2.0 app. The app contains instructions for heaps of WeDo projects, and an image-based coding platform that communicates with the smarthub via bluetooth. For us, a big benefit of having the project instructions within the app is that they’re all in one place, and they can’t get lost or damaged. The app is a very big download, just under 500MB, but once you’ve got it installed, it’s very easy to set up and get started.

How to build Liam’s Lego WeDo Windmill

Now, into the fun part… building! The best thing about this project is that you can design the windmill blades however you like. If you prefer a different colour of brick, or you like to mix-and-match, get into it. Keep in mind that substitutions are ok with any of the pieces. If you have longer bricks and want to make your windmill taller, that’s a great idea! Or maybe change some colours so it’s nice and bright. You could also decorate the front of the smarthub and motor with a cool design.

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Using the Ledo WeDo 2.0 app vs Scratch for coding

The Lego WeDo 2.0 kit comes with an app for pictorial coding, which lets you get your projects up and running quickly. The platform is very simple to use, with blocks aligned side-by-side in the sequence you want your project to execute the instructions. A range of inputs can be used, including from the tilt sensor, motion sensor, noise sensor (from your devices microphone), or from the ‘go’ button. In terms of outputs, the motor can activate, a display can show on your devices screen, or the colour of the light on the smarthub can change.

There is limited complexity that can be achieved within the WeDo app, as it’s designed for simple instructions and getting started. If you want to start coding more complex actions, consider using Scratch instead.

Scratch is a block-based coding platform, which has the ability to integrate with a wide range of hardware options including Lego WeDo, Mindstorms and Boost, BBC microbit, and Makey Makey. Importing the custom blocks for Lego WeDo lets you combine them with standard Scratch blocks to extend what you can do.

How to code the windmill

To code your windmill, you can use the Lego WeDo app or Scratch. It’s pretty straightforward, so Liam used the app. This code is really useful for lots of different projects, so you’ll see us use it all the time. In this project, there are two sequences we want to run. First, we want the windmill to spin. Second, notice that the light on the smarthub is changing colour? That’s a separate piece of code.

To start the sequence, swap the green arrow block for the keypress block. This is a really efficient way of building your code when you want the smarthub to execute more than one instruction. When you press the green arrow block, it only runs the code sequence that it’s directly attached to. If you have multiple lines of code, you have to activate each block separately. It makes far more sense to click once, and run everything. That’s what the keypress block can do. When you place it in front of multiple sequences, it will activate all of them.

Make your windmill spin

To make the windmill spin, you need to set up the motor, so you’ll be starting with green blocks. Add the motor direction block first, followed by the motor speed block. The motor speed block starts with the small block underneath saying “1”. Remove that by dragging it back to the menu at the bottom. Find the orange motion sensor block, and bring that in instead. Click on the block until the arrow points away from the motion sensor. It’s not a problem if you don’t, but the motor speed may behave differently.

You want the motor to keep spinning for the whole time that your code is running. To do this, put a loop around the whole sequence.

Code the windmill’s light to flash

To get the light on the smarthub flashing, drag another keypress block onto the screen. Add the green smarthub block next to it, and remove the small block underneath that says “1”. Replace it with the picture of the dice on a blue background. This block generates a ‘random’ number each time, just like rolling the dice. Each number corresponds to a different colour in the Lego WeDo app, so the light will display in random different colours. To finish off this sequence, wrap it in a forever loop to keep it going.

Test out your complete Lego WeDo windmill

And that’s it, you’re ready to go. Connect your smarthub to the app, and click on one of the keypress blocks to get it all going. If you want your windmill to spin the other way, click the motor direction block to swap it. This is a super quick way to make a change, without removing and replacing the block.

Ready for more Lego WeDo projects?

Liam has been sooo busy recently designing new projects, and he’s building them incredibly fast! Here are some of his other projects that you might like to try. (Click on any project to check it out).

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