In The Christmas Spirit – Build Liam’s Lego Wedo Reindeer

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Last week, Liam built a Lego WeDo Christmas tree that spins and lights up. This week, continuing the Christmas theme, he’s designed a Lego WeDo Reindeer to add to the collection. We’ve put together a full set of downloadable instructions, so you can build it too. You can find the instructions further down this post.

The reindeer is made with 100% Lego WeDo, so you can build this even if you have no other Lego pieces whatsoever! Some creations need a few extra bits and bobs to get them looking really special, but this one is a perfect all-in-one package.

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 Reindeer

The reindeer uses no Lego pieces other than what’s in the standard Lego WeDo 2.0 core kit. As long as you’ve got the kit, you’re ready to get started right now. He uses the motor for his movement, with gears driving his front axle, and the Lego WeDo smarthub sits on his back. The motion sensor is hidden on the back of his head, and we’re going to use some clever coding to get the reindeer doing a few sneaky tricks later in this post!

In terms of the structure, the reindeer is based on a fairly simple design. An A-frame gives him the body, and axles fit through the holes in the Technic beams to carry the wheels. There’s no gearing on the back wheels – he’s a two-wheel-drive reindeer! The back wheels simply follow along. His head is secured just above the smarthub on the back, and is designed to swivel.

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 Liam’s Reindeer

The reindeer uses a very straightforward piece of code, so you can put it together very quickly. If you want to follow along with video instructions, have a look at the second half of the video at the top of this post. We walk you through the code step-by-step in the Lego WeDo app. It’s also detailed below, so keep reading if you would like to know a bit more about how it works.

Let’s get started!

Essentially, this is a one-line code, which is awesome!

Start with the green arrow block. There’s only the one line of code for this, so the arrow works perfectly. Now, let’s have a look at what we want the reindeer to do. It really helps to think through the instructions like a sentence before you start. The instructions for the reindeer go something like this:

Wait until something comes close, then move forward. Keep moving forward until that something moves away again, then stop. Keep doing that until we turn you off.

This gives us a pretty good idea of how to structure the blocks.

Wait

Start with a ‘wait’ command. Remove the blue number block from the bottom, and replace it with the small orange motion sensor block. Click on the block to change the direction of the arrow, until the arrow points towards the sensor. This is the part that says ‘wait until something comes close’.

Move Forward

Now, let’s do the part that says ‘then move forward’. Add a motor direction block, followed by a motor speed block. Don’t worry about which direction the motor is set to at the moment – you’ll test that later. Liam used speed 8 for his motor, so start with that. If you want a speedy reindeer, crank it up to 9 or 10.

Keep Going

You’re doing an awesome job, so let’s keep going with the next piece. This is: ‘keep moving forward until that something moves away again’. Pick up the green motor block with a timer icon, and add it to the code. Remove the blue number block from the bottom again, and replace it with the motion sensor block. This time, set it so the arrow points away from the sensor.

Stop

The next block to add is for the part that says ‘then stop’. Can you guess which block you might use? It’s the motor with an ‘x’ on it. Add it to your code, and you’ve finished the second sentence.

There’s just one instruction left that you need to give to the reindeer. That’s the piece that says ‘keep doing that until we turn you off’. Grab a yellow loop, and drop it around the whole sequence you’ve built. That will keep the sequence going forever (or until you turn it off).

Awesome work coding your Lego WeDo Reindeer! Now connect him to your Lego WeDo app, give him lots of room to run, and press the green arrow. Move your hand close to the back of the reindeer’s head, and he’ll start moving forwards. Move your hand away, and he’ll slow down.

For more Lego WeDo Christmas Spirit…

Have a look at Liam’s Christmas tree. It’s such a cool project, and you can decorate the tree however you like!

And to try some more Lego WeDo projects…

Have a look at these fantastic projects that Liam has put together, and give them a go. Let us know in the comments if there’s a particular animal, machine, or Christmas essential that you would love to see!

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