# Lesson video

In progress...

Welcome to lesson five of our selection in physical computing unit.

I'm Andy, and in this lesson, we're going to be designing and building a model to control with our Crumble.

This lesson you'll need a Crumble starter kit and you'll need a pencil and paper.

Later on, you'll also need some building materials, but you'll be able to sort those out at that time.

Other than that, please clear away any distractions, then we can start.

In this lesson, you're going to design a physical project, which will include selection.

You'll identify conditions that start actions.

You'll be able to describe what your project is going to do, and you're going to create detailed drawings of your project.

So far in this unit, you've used more than one output device, you've used count controlled loops, and you've used selection.

You're going to have a look at some programme.

Now there's two different pieces of code next to each other.

And I'd like you to look at them and see whether they meet the criteria on the slide.

So you're asked whether it meets the criteria or doesn't and have a look at each piece of code and see whether it does or it doesn't meet it.

Sometimes it could be one or the other or both.

Okay, so pause the video now, please.

Okay, so let's have a look at those together then.

So we had our two programmes, programme one and programme two, and we had the different criteria.

The first criteria was, did the programme use three output devices? And programme one has motor one, sparkle zero sparkle one SO that's one, two, three, output devices.

Programme two just controlled sparkle zero.

The next one is, did it use a count controlled loop? Programme two use the count control loop.

Here it is.

Do two times.

Did either programme, both programmes use selection, and yes, both of them did.

Both of them had if then statements at the starts of them.

And did either programme use a loop to repeatedly check if a condition had been met? Programme two has this do forever if this happens and there's the forever loop continually checking it.

So how else could selection be used? We're going to think about selection now in the real world.

How could it be used to control something in a house? So think about things in our house and how they might be controlled.

And might there be a condition if something happens then something switches on or off.

So I'll give you a moment to think.

So here's an example.

Forever, if it's dark, turn the lights on.

So there's a simple algorithm, which is makes making the lights automatic.

So we're going to have a think now about using an if then structure to write algorithms that might be used to automate a house.

So you need to think about conditions and actions and how often the condition needs to be checked.

So your task is to write some algorithms, which includes selection, okay.

And it's for that house that we've been looking at or for a house.

So please pause the video now.

Okay, I hope you got something of that.

So here's two examples.

And the first one is, forever if it gets dark, then close the blinds or close the curtains.

Okay, here's another one.

Forever if the temperature is less than 16 degrees, put the heating on.

So the house might have automated heating, which comes on when it gets cold.

So you're going to be doing a design.

You're going to be drawing a design on paper, and it's going to be for a carousel or chair plans, like the picture.

And it's gon, it needs to use at least two output devices.

So just look at the picture and have a think about what parts you could make and how you make them.

And also have a think about the output piece, output devices you're going to use to go with that.

I'll give you a moment to look at the picture to think about it.

Okay, so we have something which spins around.

We might have some kind of light on it somewhere and we need to be able to control it somehow.

Okay, so there's some thoughts.

So what you're going to do is you're going to do a sketch and you need to think about the materials that you need.

You need to decide which output devices you're using.

Is it going to be one sparkle and one motor or a sparkle and another, sparkles, or a sparkle and a motor.

So it's two output devices.

How will your model use selection? Does it need a button or something like that to make it start or stop? Okay, so you need to draw a label diagram of your model and construct a wiring diagram, which shows how your Crumble is going to be wired up to your model.

Okay, so those instructions are in the worksheets.

So if you'd like to pause the video, now you're going to do a sketch of a model and include the wiring diagram.

Pause the video now.

Okay, so here's my design.

I've gone for a kind of cardboard tower in the middle and the cardboard disc on top, with the chairs hanging down on string.

I've got the approximate size is 25 by 25 and some props at the bottom to make sure it stays up.

And I'm using a motor drop here and a wheel.

So this disc on top sits on the wheel and I've got a sparkle down here.

And then over here is my wiring diagram showing the, the batteries and sparkle and motor and push switch that I want.

So that's my design.

So your next task is going to be to actually make your model and connect the components onto your model and put the circuit altogether onto the model.

So you're building your model and putting everything else onto it.

Okay, so here's a photograph of my model.

I went for, here's the tower and the disc at the top with the chairs hanging on string at least to try and make the whole thing stay up.

And I put a slot in, so the motor can be fitted into the top.

And then this shows it with all the bits attached.

So there's the motor and the wheel, and I've used rubber bands to hold on the different components.

So I can move around a little bit.

Just whether the photo is taken, these don't touch it.

It will turn around without touching them.

And there's my push button.

So that's my design, already, so young.

So in this lesson you identified how selection could be used in real life examples.

We looked at that house and you designed and built a model, which you're going to control in the next lesson using a Crumble.

That's it for this time.

If you'd like to share your work with Oak National, perhaps some photographs of the thing you've built, please ask your parents or care to share your work on Instagram, Facebook, or Twitter, and use that tag @OakNational and #LearnwithOak.

So see you next time, when we're coming to make our models move.