In The Christmas Spirit – Lego WeDo Sleigh

Share this!

Christmas is all about tradition. But sometimes, you need a bit of weird and wacky… With life generally disrupted over the last 18 months, we’re all going a bit wacky, so why not take Christmas that way too? Here’s a Lego WeDo Sleigh, complete with bobblehead Santa/monkey (we can’t agree on what this creature actually is)… But he was fun to build, and freaked the puppy out when he went racing across the carpet towards her! We adjusted some of the gearing after that incident, so you won’t have to worry about causing terror for your own pets.

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.

Building the Lego WeDo Sleigh

Building the sleigh involved some pretty intricate design (and a bit of redesign). The first version drove incredibly fast, but the bobblehead barely moved at all! With a few tweaks and adjustments, the end result is fantastic.

• 

• 

Learning to use gears does take some time, but it’s very definitely worth doing. There are a few key gearing concepts that Liam used in the Lego WeDo Sleigh design – here’s some quick tips that will help you too:

• A small gear attached to a large gear will cause the small gear to turn really fast. This is useful when you want to drive something faster than the motor speed.
• Double-bevel gears can interlink either side-by-side to a standard gear, or at 90 degrees with another bevel gear.
• Think of crown gears like ‘single-bevel’ gears. They can only connect at 90 degrees, not in a straight line.
• Worm gears work like a never-ending rack gear. The teeth are steadily moving along, and keep going as long as the axle is spinning.

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.

Coding the Sleigh

For the sleigh, Liam used the Lego WeDo app. It’s a very simple piece of code, and it took him no time at all. You only need one line of code, and a couple of blocks. Just like the reindeer, it helps to think of the code like a sentence.

When the green arrow is pressed, start the motor, and set it to whatever speed the motion sensor detects. Keep checking the motion sensor for changes, and change the speed as needed.

Here’s the code.

Use a motor direction block to start. Either direction is fine – you can change it if the sleigh reverses when you test it. Then, add a motor speed block next to it. Remove the blue number block from the bottom, and replace it with the motion sensor block. Click on the motion sensor block until the arrow points towards the sensor. To make it keep checking for sensor inputs, add a loop around the sequence.

And that’s it. Super easy code, and very quick to put together.

For more Lego WeDo Christmas Projects…

What would you like to see next?

Do you have a great idea for a Christmas-themed Lego WeDo project? If there’s something particular you would like to see, or wish you knew how to build, leave us a comment below, and we’ll get right into it for you.

There are some exciting projects coming out over the next couple of weeks. Make sure to come back and grab your free instructions for those projects too! Before you know it, you’ll have a full Christmas collection!

Share this!