Ch4 - Launcher
The possibility that alien civilisation exists somewhere in space is a thrilling one. It has been inspiring people throughout the ages. A Roman satirist, Lucian of Samosata, wrote a satire in 2 AD about a man travelling to the moon and meeting unhuman creatures there.
In the Japanese Tale of the Bamboo Cutter, an old couple find a baby in the woods. The baby turns out to be a princess from outer space.
The subject of "aliens" found its place in our culture as well, ever since the mass media such as television and radio gained popularity.
The aliens are shown in different ways, but mostly they are invaders wishing to either conquer or destroy the planet Earth and its inhabitants. The fictional "aliens" behave towards humans just like people did when brutally colonizing new lands.
One of the most important books about aliens is the "War of the Worlds" from 1898. The radio dramatization of the book, broadcasted in 1938, caused an outburst of panic among the listeners, who believed that a war of the worlds was actually taking place.
An alien invasion is not always treated as a serious topic. In the movie "Mars Attacks!" from 1996, aliens are caricatural, colourful monsters impervious to human weapons. They could only be hurt with a soundtrack from an American operetta.
Most of the movies, however, treat the idea seriously, for example “Pacific Rim” or “Independence Day”.
Sometimes, human military forces are not enough to stop the alien invaders. In the movie series "Godzilla", the monster often helped people to fight giant aliens, in the process destroying the city it tried to protect in the first place (usually Tokyo).
Computer games often follow the same path as movies. Usually, the player has to defend humanity from an alien attack.
A classic game in this genre is "Space Invaders". One of the first computer games, it was published in 1978 and quickly gained popularity. Personal computer Atari 2600 owes its success to this game, as it was mainly bought by people who wanted to play "Space Invaders" at home.
The game does not have a happy ending. The player’s task is to defend as long as possible, but the invaders always win in the end.
Is it even possible to shoot in outer space? Conditions in space are so different from the Earth, that almost every aspect of shooting needs to be reconsidered.
Firstly, the weightlessness in space means a problem with the kick. On Earth, a launcher is firmly set to the ground when shooting, so the kick is neutralised. In outer space, every shot will throw the shooter back from the direction of shooting and the bullet will go slower.
The only space test of a conventional weapon was carried out in 1975 on a soviet space station, Salut 3.
An automatic cannon used at the station was actually borrowed from a soviet airplane. The cannon was firmly set to the station, so to aim, the whole station had to be turned.
At the end of the mission, the crew was ordered to fire test shots. The target was destroyed. The cannon had a strong kick, but it was used to turn the station as desired.
Another problem are explosions in outer space. Ballistic rockets are devastating, because of the wave generated during the explosion. This wave is a quickly moving mass of air.
There's no air in outer space, so the explosions would be fairly harmless.
Build
To build this construction, you will need LEGO Education WeDo
Explore
This robot is a remote controlled launcher.
The construction contains electronic elements, a worm gear transmission and a piston.
The launcher fires a small brick. It is achieved by the piston pushing the brick out the beam slot.
1. The hub allows you to connect the Launcher to the computer, it powers the motor and receives the information from the sensor.
2. The motion sensor is used in the control program.
3. The launcher fires upon activating the motor, which propels the transmission.
1. The Launcher is equipped with sights, to facilitate aiming.
2. Rotating the robot freely is possible thanks to these handles.
1. The transmission propels the piston, which pushes the brick out of the slot. A piston is a device changing rotary motion into linear motion.
The rotating crank is attached loosely.
2. The piston can push the brick out only after accumulating a sufficient amount of power, which is why the Launcher fires further, when the brick is tightly pressed into the slot.
1. Here is how you can load the projectile into the Launcher.
The worm gear transmission is made out of a worm and a worm gear (gray cogwheel). This type of transmission can generate a lot of force.
1. The axle with the worm is propelled by the motor.
2. The axle with the worm gear rotates 24 times slower than the motor.
Program
Program for the launcher will be composed of several scripts. The first one will activate the motor, the second one will stop it and the third will use the motion sensor to program the sights.
Let's begin with the starting block. This time, you will need the Start On Key Press block.
