This is a mechanical cannon that uses the mechanical strain on the plastic LEGO beams to shoot a ball. Because of that the Ball size is very important. It is made to work with standard balls for a ball pool and even better with 41250 52mm LEGO Ball. The mechanism is powered by an EV3 Large motor.
Building instructions for a steering car. The front wheels steer through a Medium LEGO EV3 motor while the rear wheels are both driven by a single Large LEGO EV3 motor.
Today’s task has two main parts – the part consists of the main tasks and the second one – of the additional ones.
You should first solve the tasks for forward movement of the two motors for 2 seconds. Remind students they should be careful with their fingers.
For the next task you might have to show your students where the Port View on the computer is.
Then students should read a text on the logic of the program. You can give them a summary or leave them read the whole material.
At the end of the main tasks the program will use the Switch block in order to check whether the robot has hit the obstacle. If the program does not always operate properly, you could add some degrees to be sure it would detect the hit.
The additional tasks are meant to be more difficult so you better leave your students struggle a bit. Make sure you explain how the rotation sensor reset block functions. For convenience, this information is given in the materials.
Students should add a loop in the program which repeats it all. To make the program functioning, students should repeat the program from 0 degrees which is why the reset block follows the switch block.
In order to avoid checking whether the robot has hit anything every 2 seconds, the check should be set at 0.3 seconds.
To prevent the robot from stopping suddenly, students should use the Coast setting of the move block instead of Brake. As students have practiced this only once, you should help them with the task.
You can download the programs for the robot from here: https://www.fllcasts.com/programs/u9qxaw-program-for-the-ev3-ram-robot-hrutur
This program is for Lifter - an attachment for SUV Box Robot and Into Orbits M09–Strength Exercise material. In this program you may need to change the values in the Wait - Color Sensor blocks if the program is not working properly. The program ses also Gyro sensor, that mean that you have to check do you have a gyro drift. If you have such, turn of the robot and start it again. After turning it on, do not touch the robot until it is completely loaded and ready to run. In that way you are going to cancel the gyro drift.
We will share the idea behind that challenge and how to conduct the challenge in a classroom.
A chassis built with LEGO Mindstorms EV3 parts designed for World Robotics Olympiad
