Lesson video

Today's lesson is all about bionic animals.

And we're going to be looking at motors and you're going to be designing your own bionic limbs.

So let's look at the equipment that you'll need today.

You will need cardboard, a pen, some scissors and tape.

And if you've got it, a ruler.

Don't worry if you haven't got brand new cardboard, using old packaging is absolutely fine.

You might want to pause the video now and go and find those things.

So let's look at what we're going to do in today's lesson.

Well, you've probably already done the intro quiz.

We are then going to look at what the word bionic means.

We're going to look at motors and sensors.

You're going to design your own bionic limb, and then we're going to see if you're ready to go bionic.

And as always, there will be an exit quiz.

So let's look at the keywords in today's lesson.

Bionic is a technique of replacing body parts with electronically mechanised parts.

Now, they're different to prosthetics.

Prosthetics do not move, whereas bionic body parts have motors and they move.

They have sensors and they're electronic, okay? So bionic, and that's what we're looking at today.

Second word is microswitch.

Now this is a physical switch that reacts to movement and change.

Sometimes you find them on machinery and when you close the lid on the machinery, it clicks a little switch, and that means that the machine will then work.

You have them on washing machines as well.

If the door isn't properly closed and the microswitch isn't close up, then the machine won't work unless that switch has been activated.

So, last word for today is output component.

Now, I know you know about input process and outputs, but we're really going to focus on some of those output components today.

And these are things that create function within a circuit.

So they might be something like a buzzer going off or an led or a display, giving a message, something like that.

So we've got three keywords for today; bionic, microswitch, and output component.

We've got a microswitch.

Now this is a switch that has a long bar that usually is hit by something moving, which will turn a circuit on or off.

Okay, we're going to have a little look at microswitches in a bit more in the moment.

We've got a motor and this takes electrical charge and it spins.

So the axle at the front spins round and round and it can go either way, forwards or backwards.

And then we've got a push to make switch.

Now this push to make switch, only stays on as long as the button's been held down.

If you take your thumb off the button, it will stop.

A bit like, games console or something like that.

Okay, quick question.

This is a picture of a push to make motor.

Is that true or false? What do you think? Let's have a look, yeah, it's false.

What is it then? That's right, it's a microswitch, okay? Can you remember where I said microswitches can be used? Yeah, that's right, they can be used on things like washing machine doors, to make sure that the washing machine doesn't start its cycle without that little click that you hear.

And that's, if you look at the microswitch on the screen, there's a little brown button at the top.

That's depressed, it's pushed in by the lever being attached.

And that's what makes the click sound.

So let's look at our microswitch in a bit more detail.

Here's a diagram.

If I cut that microswitch in half what I would find.

The common at the top is where the power goes in, and then you've got two states, normally closed, which is where the lever will sit and normally open.

If that lever, which is at the bottom, pushes up, it will push the switch into a normally open position, which might start a motor or make sure a buzzer goes off or something like that.

It will sound an output.

Let's look at what it would look like in terms of an electrical symbol.

So this is what it would look like.

So we've got our power coming in, sitting in the normally closed space.

If it's activated, it would go up to the normally open.

And in this example, I've attached a red LED and a yellow LED.

Talking of electrical symbols, let's see if you know any of these.

So here we go.

Here's, we've got a battery at the top.

Do you know what the next thing is? Let's have a little look.

Yeah, we've got a motor.

So a circle with an M is a motor.

Do you know why this arrow's attached to the motor? That's right.

It's a direction in which they're going; clockwise or anticlockwise.

And our microswitch which we just look at.

Great.

So, let's have a look at our microswitch in action.

The microswitch, here are two little microswitches, and you can see how small they are compared to my fingers.

And on the back, we have got this lovely lever.

And if you listen, you can actually hear the click, okay? So normally close, normally open.

And then we've got our three prongs for attaching it.

The two holes in our microswitch are used for screwing it on to whatever devices it's being used for.

So you might have something where a product rotates and then it clicks, lands on it and the circuit stops.

Or you might have it that the circuit's open and then it comes around and clicks, and it let something happen.

And you can actually see as I'm holding this, you have got the common.

So that's where you attach it to the power.

Normally open and normally closed at the back.

They've actually identified on the component to help you out.

So the common, which is where the power would go in, the normally closed, oops, see, let me get it in the light, sorry.

Normally open in the middle and the normally closed at the end.

There you go, just about see it on there.

So let's look at this in a circuit to help you understand a little bit more.

I'm just going to pull my camera a little bit, there we go, loving this.

So, in this example, I have got some batteries.

I have, they come out of the positive, into the common, so that's your power.

And then into the normally open.

Because we know that in this position it's normally closed then from the positive into the motor and then out back into the battery stack.

So if I look, I've just glued on a tag so you can see which direction this goes in.

If I close my microswitch, my motor turns clockwise.

Off, on.

Off, and that's where I touch.

And all the time it's clipping, clicking, sorry.

Now this is a good down rate as it's going slower than it normally might.

But if I was to use a servo motor, that works on angles, and that would stop for me on set angles all the way round.

And if we were doing our bionic legs for real, when we were at school, those are the motors that I would use.

There we go, so we're going clockwise.

Now, let's have a look at this over here.

Exactly the same setup.

Let's see what happens.

This one is going anticlockwise.

I've still got it attached to the common and the normally open.

So what could the difference be? Let's have a look.

Put those circuits together.

Can you see the difference? Can you see any difference? Have a look.

The different makes of batteries, it makes no difference.

Have a look at that wiring up, what is different? Can you tell me? Fantastic.

This one, the positive and the negative are round the other way, can you see that? So we've got the negative on the left, positive on the right.

Then we've got the positive on the left, negative on the right.

And if I put them together, they're working.

That one's going anticlockwise.

They're working in different directions.

Now, if you wanted to, you potentially could wire these up into one motor.

So you could make one motor, if it was open, going in one direction, if it was closed, going the other direction.

But I just wanted to show you, thought this was a much better way of showing you how microswitches can be used, okay? And obviously we can use different outputs but today, I've chosen to use motors.

Here we come to our favourite bit of the lesson.

We have got a little bit of a bionic challenge for you and the dog sniffing the camera is probably a good clue.

I want you to choose an animal, a pet of your choice, and you're going to design and model a bionic leg for them.

Now, if we were in school, we'd have motors and we'd have microswitches and you could include those in the design and get it working.

But for now, we're just going to do the designing bit including the switches, and I'm going to get you to model in 2D or 3D, some of those ideas out.

Okay, so, let's have a look at the brief.

Using the motors for movement, we're going to design a model, a bionic limb for a pet at home.

Great.

Let's get some more detail on that.

So, I've got the horse here and you can see, that in the skeleton of the horse, I have got the back leg and I've identified three main limbs, and have also looked at how they rotate, how they squash in.

If you think about your knee, you can't move your knee 360 degrees.

You can only really move it, maybe just under 180 degrees, okay? So think about how much movement we want to replicate.

So we're imagining that that limb isn't actually there, okay? So if we're replacing it with a bionic leg, how might that leg look? In my next film, I'm going to demonstrate some ways of sketching out your leg for your per that you'd like to choose.

And after I've done the drawing for the video, I'd like you to come up with a set of different ideas to get you started.

And then, we're going to move on and do some modelling.

I'm going to sketch out for you some of my first sort of rough ideas really.

You might find that modelling first actually helps you rather than sketching first.

But you sort of got to work out which way around you like doing things.

And you can, at school, I would normally say for the students to sketch in pencil, but it can be hard for you to see what I'm actually sketching.

So, I'm going to sketch in Biro, which is quite nice 'cause you can sort of, make bits darker and have some bits lighter and stuff like that.

And when you're sketching, you might find that after maybe two or three ideas, you sort of run out of ideas and some of the ones you're coming up with aren't very good.

But don't worry, because often, that just makes the ones that are really good, look even better.

Okay, so I've popped one in.

Let's do another one with, some bits.

Now, as I'm designing, I'm loosely thinking about designing for an animal.

So I am sort of thinking about a horse, still.

So I might need to bring in some really, some nice chunky bits and pieces.

And also thinking about maybe, what materials these might be made from.

So they could be 3D printed parts.

Maybe they're made from something like titanium.

Parts that are new joints and things like that, that go in the body are made of a titanium alloy.

'Cause they have this, and the alloy being a mixed materials, because it's got the strengths of titanium.

But it's also alloyed, so that it's lighter.

And especially if you're putting, new hips and things in elderly patients or very young children, that's really going to help.

Also, some joints and things are ceramic now.

When I had my ACL operation on my knee, I tore my cruciate ligament, they put 3D printed parts in my knee.

I mean, how cool is that? I'm a tech teacher and I've got 3D printed parts in my knee.

So the materials in prosthetics and bionic development and things like that, are developing all the time.

And that means that the actual designs can be more refined, they don't have to be as clunky, they last longer, all these cool things.

Okay.

So I know you're itching to get sketching, and it might be that you're sketching at the same time that I'm sketching.

Don't worry, if you want to copy some of these ideas, rather than coming up with your own to start with, to get you going, that's absolutely fine.

Sometimes people like sketching and listening to the radio or listening to music.

All right, there's my first three.

Have a go, see how you guys get on.

So now we've got our sketches and you've had a go at sketching out your own design ideas.

I now want you to have a go at doing some little 2D models.

And when you're modelling this, I'm going to give you a little demonstration.

And in my demonstration, I'm going to model it very flat.

What I would like you to think about is, the rotations of the knees or the ankle joints that you might have for your pet.

And I've sort of demonstrated it in the diagram on the page.

That grey circle and showing the angle that it potentially is going to move.

'Cause that's where we're going to put our little microswitches in.

So when the leg would move down, it would hit the microswitch and stop the motor.

Okay, I'll explain that a bit more, when we get a little bit further on.

So have a go at 2D modelling.

Okay, so what we're going to do is we're going to have a go at modelling out some of these design ideas that we've sketched.

And it's fine if you want to copy what I've done, to give you some inspiration, that's fine.

Now, I'm using Sellotape to stick mine together 'cause it's actually quite difficult to glue like tiny little pieces.

I've just found a bit of red card that's around.

So I'm going to start and I'm going to have go at modelling this one.

Now, the main thing is that I'm not going to worry too much about doing it exactly, and if I think the design needs to be developed, then I can do that.

It's not very straight, is it? That's better.

Okay, so that's the top bit.

Now, I'm going to do this bit.

Now, to try and cut in and around, I think I'd find that really difficult.

So, I'm going to cut a piece for down through the middle.

Okay, underneath.

And then these bits getting across.

I think I'm just going to cut some bits like that.

And what we're looking for when you're designing is all the time thinking about how you can make things better.

How can you move your design forward? Oops, actually, that looks quite good.

So, what I'm going to do at this point, is I'm just going to stick a bit Sellotape over the top of it.

And that will stop it moving.

If I had, better glue, I would you use it.

Obviously, if you want to you can flip it over, that's up to you, you can have a mess around.

I just want to keep everything still.

Right.

I'm going to trim off that.

And I can have it, I can neaten all of that up in a bit when I'm not demonstrating it.

Okay, so that's the top bit.

Now, this piece here I could draw as one, and then go into this section.

So I'm going to do this section first.

So grab a bit of Scrappy-Doo card, working out how big that is.

This a bit like a fish skeleton, isn't it? Okay, and that bit on there.

Yep, quite like that.

If I want it angled like that.

And the really nice thing is, if I was designing this and I had a bit more equipment, you could take photos of it in different angles and things like that, which might be quite nice.

So I'm going to leave that one on there and.

Also if I was doing, I'm using colour cards so you guys can see the difference but if I was designing this, if I was at school, I'd probably use white card and then go around the outsides, to show it really nicely.

So have it standing out, and not have to fix something on there.

And then I need sort of a square piece going across the top.

And that goes over like that, okay? And this right on to that.

How does that look? Yep, quite like that.

Now, I'm going to draw in some little bits of detail on that.

Like that, how's that looking? Yeah, that's all right.

And then, like I said, I could go round here drawing it a bit.

This is quite dark card.

If I was using lighter card, it would look that.

Okay, and then whoops, it moved.

Then I'm going to get a bit of tape so it doesn't move.

If my hands can start wiggling, scrub a bit of tape.

Let's put that back.

Here we go, absolutely stuck together.

So, it's up to you when you're designing, you might be the sort of person that likes to model first, then sketch off of it.

You might be the sort of person that likes sketching first and then modelling.

But all the time, it's about your ideas developing.

You don't always have to create, the most perfect design idea, and then it always stays like that.

So if I was moving on forward now, I might do a little arrow onto here to show that I'm going here next.

And then I might decide that I'm going to play with this, so that little bit sketch there.

Show a little arrow of it moving.

It might be that you then want to show it flexing the other way.

Oops, other way.

And that will give you movement here, wouldn't it? Okay, so your challenge now is to go ahead and get modelling, in 2D.

I would like you to pause this video now and make yourself some 2D models.

And when you're finished, I'm going to show you an extension that you could do today, to make your 2D into 3D models.

So pause the video now and have a go at making those 2D models of your initial sketches.

Okay, so modelling is all about trying new things and testing out.

So once you've got your little 2D models, breaking mine now.

Once you've got your little 2D models, I want you to move on and have a go at doing 3D.

And I'm going to show you how easy it is.

Little bit of corrugated cardboard, okay? We've all got bits of, you know, packaging from stuff.

Split it in half.

You can make some pieces for in between.

Take them down like this.

Okay, so you make almost like you're making an H.

Okay, some little bits in between.

Take this together, and then here's a little H I've made and I've squeezed it in together to make for my legs.

Now, it can be that I, you know, if I want this shape, maybe I make some long shapes to go on the outside or something to get some of this lovely detail and definition.

But I just want to show you, I don't have split pins at home, but I did find some little screws.

So don't take them out of something important for goodness sake but they're really good, 'cause you can screw them through.

There we go, there.

Moving knee joint, whoop, whoop.

Okay, so I'm going to attach here the side.

Now, what I wanted to sort of show you, in your sketching pages that you are doing, now if I was doing this at school, I might get my students to take photos.

But in my sketching page, I've got my sketches.

I've got my lovely little 2D models.

And now we're going to develop this onto my 3D model.

And my leg, I've now got my knee moving.

Now I want to get the movement from there to there.

And I want to stop.

I want the movement to stop.

So what I'm going to do is I'm going to bring in, our lovely motors.

So, now this really is a bit of trial and error and it might go, hopefully, it will be absolutely fine.

I'm going to take out one of these little screws, and I'm going to attach the back of this motor.

Now I know you haven't got this at home and that's absolutely fine.

The reason I'm doing this is to show you how we could progress this further.

And also for your designing, what you could add.

So, I've just popped in a little bit of magic glue.

I'm going to glue the shaft of the motor on the back.

I don't want it to glue onto that.

That's glued onto that, so hopefully, that will move.

That's still free, amazing.

So the idea would be if it was closed, like that, I put the microswitch on, make sure you're seeing the back of that, and it moves.

Let's just rewind that.

Press the marker switch again, our lovely bionic leg.

I'm going to do that one more time, 'cause I can't believe how well, it's actually worked.

Let's close it back up again, press one little microswitch, and out it goes.

So when you're doing, your designing, think about how you could start to bring some electronics.

Oh, look, it's not working now.

There we go, it slipped.

How you could bring some electronics into your legs.

So your final task today, is starts to take your ideas, your lovely sketches, and your lovely 2D models you've done, and start to develop then into a more 3D way.

And it would be really nice if you start to think about how you could introduce some little servo motors, that just move in one little angle, and how you could attach those onto the back.

Okay, give it a go.

Let's have a go at answering some of these really super quick questions.

A microswitch will rest in a normally closed position, is that true or false? What do you think? A normally closed position.

Let's have a look.

Yeah, it's true, well done, excellent.

You probably remember those diagrams we've looked at today.

Let's look at this.

Okay, so we have got a circuit drawn out here.

At the top, we've got the battery, it goes round to the switch and then you've got two motors wired up either side of those points on the microswitch.

So, in this position, the motor will be turning clockwise.

Is that true or false? Have a look at the arrows, what do you think? Yeah, it's true, well done.

Fantastic, great knowledge.

I hope you've had a great time today.

Sketching and doing 2D and 3D models and thinking about how we can create movement on our bionic limbs.

As always, share your work with your teacher.

I'm sure there'll be really excited to see what you've done, and we'll see you very soon.