How do we know when we should stop loading the catapult? How does the brick know that we should stop the motor? For that purpose we'll use an NXT sensor. There's one problem that we are going to face. Now, the next thing will be to develop a program for our motor so to be able to load the catapult. So, we load,Įngage both gears, the clutch is on, then we release the clucthĪnd we fire. When we release the clutch, we fire an element. The clutch is working, so one of the gears engages with the other. Now, let's attach this very interesting construction to our robot. We have, let's say, a verticle axis which transfers power to a horizontal axis.
#Lego catapult how to
How to change the orientation of gears? The name of the video is Active attachment for changing the orientation of gears. One thing you can see about this module with a clutch is that we are changing the orientation of gears and we have three or four videos on this subject so you can check them out. In this way we could, for example, have the gears engaged while we are loading and then we disengage the gears and we fire an element. When we move the lever, when we move it down it engages, when we move it up, it releases. But the purpose of the clutch is to engage this black wheel and the small black wheel. After we attach it, you'll completely understand how it works. The clutch is a very interesting mechanism and the purpose of the clutch is to engage two gear wheels. So, the motor should bring the lever down - like this. We are using a motor only for loading the catapult but for firing we should again use the gravity force. So, we should again use the gravity force for firing.
![lego catapult lego catapult](https://s3.amazonaws.com/fllcasts/content_pictures/pictures/000/001/508/56d94ed0e6bebb8c5bfccb5773d1bf9befde8ea2Lego-Mindstorms-Ev3-Catapult-Robot-With-Sensors-and-Motors-Fllcasts.png)
So, where should we put this NXT motor, so that we can transfer power from the motor to the gear wheel? One requirement that we have for our construction is to be able to fire an element with only a push of a button or a push of a lever. In this video I'm using the NXT version of Mindstorms but in the next video we'll use the EV3 version. Now, the challenge is where we should put this NXT motor. In this way we could load the catapult we turn the lever, we load the catapult, we release the gear wheel and we fire an element. The first thing that we should do is to attach a gear wheel to the axle over here. For that purpose, we would use a motor and a very interesting clutch that I have developed. In this episode I'd like to improve the robot so that we could load and fire different elements completely automatically. And it's quite stable - you can turn the robot and you can fire small Lego parts using the gravity force.
#Lego catapult series
In the previous episodes of the series on how you can construct your own catapult I showed you how you can construct the frame of the catapult, the nest, the base. The current video lesson shows the robot built from LEGO Mindstorms NXT parts while the next one would use LEGO Mindstorms EV3 motors and sensors. How to use the Ultrasonic Sensor with the Catapult built from EV3/NXT (Part 5)Ĭatapult build from LEGO Mindstorms EV3/NXT (Part 4 - EV3 clutch and loading)Ĭatapult build from LEGO Mindstorms EV3/NXT (Part 3 - Automatic loading)Ĭatapult build from LEGO Mindstorms EV3/NXT (Part 2 - Base)Ĭatapult build from LEGO Mindstorms EV3/NXT (Part 1) Robotics Set You could find more explanations about changing gear orientation in the following video lessons:Īctive attachment for changing gears orientationĪctive attachment for changing gears direction - part 2: improving durabilityĪctive attachment for changing gears direction - part 3: moving up&down All episodes from the series: Configuring the motor to use rotations or degrees is a very bad practice and we should try to avoid it. We should have a way to find out if the Catapult is already loaded and when we should stop loading. The touch sensors used in the robot are very important. In this way the orientation of the gears is changed twice and transmitted four times.
![lego catapult lego catapult](https://i.ytimg.com/vi/3OlPrXiKVjs/maxresdefault.jpg)
The power from the motor is transferred to the lever by a system of gears located on different axles. Firing is achieved by using gravity force again while loading is achieved with a motor.
![lego catapult lego catapult](https://cdn.instructables.com/ORIG/F3V/9RWP/HXG6R04O/F3V9RWPHXG6R04O.jpg)
A motor for loading the catapult is added to the construction shown in this and in the following video lessons of the Catapult series.