Naked Engineering - Engineering with Lego!
Meera - This week on Naked Engineering, Dave and I have returned to the engineering department here at the University of Cambridge, but it's all a bit different this time, as we're surround by hundreds of first year students. And they all appear to be playing with - well, Lego. I'm sure there's got to be some kind of engineering aspect to this. Dave, what can Lego show us about engineering?
Dave - I was essentially brought up on Lego and the wonderful thing about Lego is that it's very, very quick to take an idea in your head and convert it into a 3D object. The 3D object might not be quite the same as traditional engineering materials. It's a bit wobbly, it's made out of plastic. But even with the old fashion Lego which I grew up with you could build all sorts of wonderful things. And it appears to have moved on somewhat in the intervening years!
Meera - Now, the course organiser who's put this all together - is Andrew Gee from the University of Cambridge. Hello, Andrew.
Andrew - Hello.
Meera - What type of Lego and how much of it are the students actually given?
Andrew - This is completely different Lego to the sort of Lego I grew up with as a kid. So when I think of Lego from 35 years ago, I think of little duplo bricks that you'd stick together, but when I saw this, I couldn't believe how much it's come on. So we've got Lego with motors, sensors, actuators and microprocessors; and technical parts, they can build gearboxes and springs, and levers, and all sorts of complicated mechanisms. It's a fantastic medium for constructing engineering systems, and actually learning a lot about the principles behind engineering. It's very open-ended, we've given the students an opportunity to build whatever sort of machines they want. Some of them have built machines which have taken them into areas of engineering that we don't even cover until the second year, all illustrated on a Lego system.
Meera - Now you have a lot of students here though working at the moment and in this session alone, it's half of the year. So it's 165 students. Has anything stood out in particular, amongst all of the groups here?
Andrew - I think what's really stood about amongst all the groups is they were so keen to build something different and come up with machines I wouldn't have dreamt of building. They've come up with machines that will fire a projectile at a target that you position at an arbitrary position, using the projectile theory that they've learned at school, but they're putting it into practice with the Lego. And they'll also the see the limitations of what they've learned at school and that the sums won't quite work because they don't take into account air resistance, and then they'll have to try and take that into account to learn a bit more. So what's really impressed me most has been their willingness to actually do something original rather than follow instructions.
Meera - I'm quite excited to see what's going on. So Dave and I are just going to go for a wander and see what the groups have been up to.
Dave - It looks absolutely fascinating. To be honest, I'm very, very jealous.
Josie - Hi. I'm Josie Hughes.
Catherine - Hi. I'm Catherine Sams.
Meera - So Josie and Catherine, what have you made here? It looks very interesting.
Catherine - It's meant to be like a Lego photocopier.
Josie - Well it's not really like a conventional photocopier. We have a little car that's got a sensor underneath that can detect the colour of the paper. When the light sensor sees that it's white, it just moves along, but when it sees it's black, it stops and puts the pen that's attached to the car down. When the pen's down, then if the car moves forward again, so the pen's kind of dragging along, drawing a line. And then as soon as it sees white, it stops and moves the pen up. It'll do that all the way along and then it goes back, and it'll move the paper a little bit, and then start all over again. So effectively, it kind of copies it along in lines.
Meera - And how is it working so far?
Josie - It's okay. There are a couple of hitches with the pen, pressing a bit hard on the paper and making holes in the paper, but just things that we're trying to even out so it goes really smoothly.
John - Hi, there. I'm John Hopkins. We've got here a robot device which manoeuvres around the keypad of a phone and will send a text for you.
Dave - So you basically got three axes of movement there?
John - Yeah. We've got forwards, backwards for moving down the numbers and then we go out to a rotate between say, a 2 or 3 or 1.
Dave - I guess another - something which will push down?
John - Yeah, so we've got a motor that turns a small pivoting arm to press the button and the keypad noise once the button's been pressed, in fact releases the motor.
Dave - So you got an audio sensor there that is detecting the sound.
John - Yeah.
Dave - So how is it going?
John - Pretty good, yeah. There's a few difficulties as always. Background noise in fact, it may be, that's giving us a few problems because you get a nice spike with the keypad tone.
Dave - But if someone hits the table or something, you're picking that up...
John - So it just seems to throw it up a little bit.
Dave - So, how quickly will it text? Any competition with a 13-year-old yet?
John - No, not a popular one, but I think if you were working on the computer, you had to send a text, you could write a text out on the computer, press send, leave it running alongside you, not worrying about how fast it's going to send, and then 5 minutes later, you may well have sent your text.
Hugh - Hello. I'm Hugh Carlson and I've made - well, me and my team have made a two-speed automatic transmission car.
Meera - Tell me a bit more about this car. So it's about 30 centimetres in length anyway, but what's it comprised of? What's all going on inside it?
Hugh - We've got one motor controlling the gearbox and that just drives straight into a drive shaft of the gearbox, and then they have an output onto the rear wheels. We have one motor controlling the gear transmission which slides the gears across to change gear whilst it's running, and then we have another motor attached to a steering column at the front which is responsible for choosing where it goes. And then in front of that, we have an ultrasonic sensor for detecting whether the ground in front of it is going up or down, and thus, whether we come across a hill or a trough.
Meera - A big part of it is problem solving. So what problems have you encountered whilst making this and what have you thought about to overcome them?
Hugh - One of the big ones which we had today was, we've discovered the engines which drive this can't do enough force at low speeds, so we have to add an extra set of gears to step down the motor again so that it can run on high revs and still have the force output.
Meera - And how's it functioning? Are we able to see this in action?
Hugh - Yes.
Meera - Okay, so it's starting up. So you've got it moving along a desk now and you've got it going up a slight ramp. So that's how it's detecting the change in elevation.
Hugh - Yes. It's a range detector on the front and it basically - if it suddenly changes quite quickly... Oh, sorry! The gearbox just broke.
Meera - More problem solving there, so that's good.
Hugh - Yes, there's a lot of it.
Meera - And I guess lastly though, have you enjoyed it?
Hugh - Yes, a great deal. It's playing with Lego again. Who doesn't enjoy that?
Meera - Now Andrew, Dave and I have had a good wonder around. We've seen photocopiers, pendulums, steam engines, as well as cars, as we'd hope to see too. What are you hoping they walk away with? So what kinds of skills will they hopefully now use over the rest of their time here?
Andrew - Lots of things really. I mean, from working in teams, they're all working in teams of three, the three was intentional. Three creates a bit of interpersonal conflict which is very real-world and it's a good lesson for them to learn. Simple things like basic engineering vocabulary. They all now know what a pin jointed truss is and what's a bearing is, and what's a gear is. So even if it's just vocabulary they take away. Importantly, they've learned to think in 3 dimensions, they've learned to program in MAT LAB which is a very useful engineering programming language that they'll be seeing a lot of in the next three years.
Meera - So I'll take it then you'll definitely bring this back for next year's first years?
Andrew - Absolutely, definitely. No question about it.