Robots and Physical Computing: VEX

Showing posts with label VEX. Show all posts

Wednesday, 31 May 2023

Monday, 22 February 2021

VR robot in a maze - from Blocks to Python

Recently I produced a post about playing with Vex Robotics VexCode VR blocks and the Maze Playground.

The post finished with me saying I would like to play with Python and do a Python version of it. Well it is actually very easy to do it.

You can do it in two stages from the block code. First click on the <> icon (lighted in the figure above and it gives a further view producing Python code that changes as you change the blocks. The last stage is to convert to a text project (button at the bottom right of the screen.

Example of the code.

myVariable = 0

def when_started1():

    global myVariable

    drivetrain.drive_for(FORWARD, 100, MM)

    while not down_eye.detect(RED):

        drivetrain.drive_for(FORWARD, 5, MM)

        if right_bumper.pressed():

            drivetrain.drive_for(REVERSE, 30, MM)

            drivetrain.turn_for(LEFT, 20, DEGREES)

            drivetrain.drive_for(FORWARD, 20, MM)

        else:

            if left_bumper.pressed():

                drivetrain.drive_for(REVERSE, 30, MM)

                drivetrain.turn_for(LEFT, 120, DEGREES)

                drivetrain.drive_for(FORWARD, 10, MM)

            else:

                drivetrain.turn_for(RIGHT, 10, DEGREES)

                drivetrain.drive_for(FORWARD, 10, MM)

        wait(5, MSEC)

vr_thread(when_started1())

The code in action

This is possibly a nice transition tool going from block-based programming to text-based.

Related posts

https://robotsandphysicalcomputing.blogspot.com/2021/02/escape-maze-with-vr-robot-vex-vr.html

All opinions in this blog are the Author's and should not in any way be seen as reflecting the views of any organisation the Author h any association with. Twitter @scottturneruon

Sunday, 21 February 2021

Escape the Maze with a VR robot - Vex VR

You don't need to buy a robot to get programming a robot, now there are a range of free and relatively simple to start with robot simulators to play with. Three examples are listed below:

- Make code for Lego EV3 https://robotsandphysicalcomputing.blogspot.com/2020/05/programming-robots-virtually-3-lego-ev3.html

- iRobot simulator https://robotsandphysicalcomputing.blogspot.com/2020/04/programming-robots-virtually-2-irobot.html

- Vex robotics Vexcode VR https://robotsandphysicalcomputing.blogspot.com/2020/04/programming-robots-virtually-1-vexcode.html

It is the last one of these (https://www.vexrobotics.com/vexcode-vr) that is the focus of this post and return to hit, after an earlier discussion in https://robotsandphysicalcomputing.blogspot.com/2020/04/programming-robots-virtually-1-vexcode.html .

Two of the nice things about the package, apart from being free, are it uses a Scratch-like programming language and it provides a 3D environment and models - playgrounds for a number of scenarios.

So in this post, I will be discussing playing, or rather starting to play with the robot navigating a 3D maze (see the figure above). A feature I particularly like is you can change the views from an overhead view to an onboard version or one that seems to follow the robot.

So as I starting point I programmed it to essentially bounce along the walls keeping the wall on it's right and stopping when the downward 'eye' detects red on the floor for the end of the maze. The sensors include left and right bumper sensors; along with two sensors for detecting colours one facing forward and one down. The code I use is shown below:

It took 8 minutes to solve the maze - which is slow. I would be interested to see the solutions of others being shared. As a simulated robot programming system this is great fun and challenging, I would recommend having a play iot is free and available at https://www.vexrobotics.com/vexcode-vr. I want to have a go with the Python version to replicate or better the solution above (start it as a text project rather than a blocks project when starting a new project).

All opinions in this blog are the Author's and should not in any way be seen as reflecting the views of any organisation the Author has any association with. Twitter @scottturneruon

Saturday, 25 April 2020

Programming Robots Virtually 1 - VEXcode VR

For a number of years, I have been playing with robots as a means of developing programming/coding skills with students. The problem is when classes get larger or it is used as part of an assessment there is very rarely enough robots to satisfy all the students Turner and Hill (2008). So
therefore, the search has been on for a tool that allows robots to be simulated, programmed, ideally web-based, free and simple to use. Lately, a number of interesting tools have arisen. In this series of posts, I am going to look at experimenting with a few of them. In this post, starting by looking at VEXCode VR - available at https://vr.vex.com/.

VEXcode VR https://vr.vex.com/ from VEX Robotics (https://www.vexrobotics.com/) is a simulator and programming tool for their Scratch-like programming tool VEXCode - at the time of writing is free. If you can do Scratch this is a nice next stage, consisting of the simulator (playground) and the programming environment (see below and the video above.)

Playgrounds
These are the simulated environments you can select from, with a two camera-views; downward camera for overhead view and angled camera to give a 3D view (as shown in the video) via buttons on the bottom right hand side of the playground. Also you can toggle, using the third button on the right hand side, the ability to see the status of the various sensors. There are a number of different playgrounds to play with. In this post I am going to use two of them

Example 1: The Square
Using the Grid Map playground and angled camera. I wanted to start with a stand-by; getting the robot to move in a square. The robot moves forward for 30mm and then turns right 90 degrees; and this is repeated 4 times (see below)

So the commands are very scratch-like. I was impressed, the 3D gave a clear view it in action, the commands were intuitive and (yes repeating myself) very easy to transfer to from Scratch.

Example 2: Playing with Sensors a bit
Now for more fun, getting it to react to the environment a bit; by changing the Playground to Castle Crasher you get an environment that has simulated blocks and red perimeter to interact with. As you would hope, there are sensing blocks including LeftBumper and RightBumper - no guesrss for what they do and DownEye which can detect the red line. The code is simple and shown below, based on detecting the block using the bumpers, move to the side and recheck if (shown below) is if a block is in-front and if not go forward. If it finds the red line reverse back and rotates 180 degrees.

As a side project I wondered what would happen if you didn't put code in to detect the red line, how would it cope with falling off the surface; it simulates it quite well showing it falling off which quite fun. One mistake I made initially is accidentally selecting the wrong form of turning action rotating when it should have been a turn.

Overview so far...
If you can already use movement, sensing and control blocks in Scratch, you can do this. Has potential as a source of online activity's, especially as the time of writing in the UK we are 'social-distancing'. In their paper Turner and Hill (2008) also highlighted that robots are a difficult resource to manage for a large class; this kind of option allows simulation and programming of a robot to be tried out without actually having the robot. Most importantly it is fun.

Reference
Turner S and Hill G(2008) "Robots within the Teaching of Problem-Solving" ITALICS vol. 7 No. 1 June 2008 pp 108-119 ISSN 1473-7507 https://doi.org/10.11120/ital.2008.07010108

All opinions in this blog are the Author's and should not in any way be seen as reflecting the views of any organisation the Author has any association with. Twitter @scottturneruon