Getting to Know your Robot

1. Getting to Know your Robot Dr. Paige H. Meeker

2. Text: Learning Computing with Robots Deepak Kumar NOTE: This text is free for you – it is available online. Just download it from: http://wiki.roboteducation.org/Introduction_to_Computer_Science_via_Robots

3. Setting up your Robot • You should all have successfully connected to your robot at this point and the class will continue as if you have no problems doing this. • If you have NOT done this – make an appointment with Dr. Meeker outside of class THIS WEEK to get set up. • Labs will begin at the end of the week.

4. Let’s Get Started • Double click on your Python Icon and let’s get started. You should see the IDLE window.

5. Connect to the Robot • Make sure your robot and the computer have their Bluetooth dongles inserted and that your robot is turned on. • To connect to the robot enter the following command into the Python shell: >>> from myro import * • This informs the Python Shell that you will be using the Myro library. The import statement/command is something you will use each time you want to control the robot. • After issuing the import, some useful information is printed about Myro and then the Shell is ready for the next Python command. Now it is time to connect to the robot by issuing the following command: >>> initialize("comX") • Where X is the port number using which your computer is using to communicate with the robot. • When you issue the initialize command, the computer attempts to communicate with the robot. If this is successful, the robot responds with the Hello... line you now see, and reports its name to you. • You can give your robot whatever name you like.

6. Give the Robot a Name • Suppose we wanted to name the robot “Wally”. • Use the following command: >>> setName(“Wally") • Whatever name you decide to give your robot, you can specify it in the command above replacing the words Wally. • From now on, that will be the name of the robot. • Ask it its name: >>> getName()

7. Make the Robot Beep • In the Python Shell, enter the command: >>> beep(1, 880) • The command above directs the robot to make a beeping sound at 880 Hertz for 1 second. Go ahead and try it. Your robot will beep for 1 second at 880 Hz. • Try the following variations to hear different beeps: >>> beep(0.5, 880) >>> beep(0.5, 500)

8. Let’s Review… • Each session with a robot begins by starting the Python software, followed by importing the Myro library and initializing the robot. • Then, you can issue any command to the robot. • The Myro library contains dozens of commands that enable various kinds of robot behaviors. • All commands are being issued in the Python language. Thus, as you learn more about your robot and its behaviors, you will also be learning the Python language. • One characteristic of programming languages (like Python) is that they have a very strict way of typing commands. That is, and you may already have experienced this above, the language is very precise about what you type and how you type it. Every parenthesis, quotation mark, and upper and lower case letter that makes up a command has to be typed exactly as described. While the rules are strict luckily there aren't too many of them. Soon you will get comfortable with this syntax and it will become second nature. • The precision in syntax is required so that the computer can determine exactly one interpretation for the command resulting in desired action. For this reason, computer languages are often distinguished from human languages by describing them as formal languages (as opposed to natural languages that are used by humans).

9. Let’s Drive • One fun command that myro provides is >>> joyStick() • After typing this into the Python window, you should see a dialog box pop up – this will allow you to drive your robot by moving your mouse around on the dialog box. • Give it a try!

10. Let’s Drive with more Control • Myro commands for driving the robot with code: >>> forward (SPEED,TIME) >>> backward (SPEED, TIME) >>> turnLeft (SPEED, TIME) >>> turnRight (SPEED, TIME) >>> translate (SPEED) >>> rotate (SPEED) >>> stop() • Try them out! (TIME is in seconds.) • NOTE: translate and rotate don’t “stop” on their own – the robot moves until you type stop().

11. Look at your Robot – More Movement Commands • Take a look at your Scribbler - there are three wheels. Two of its wheels (the big ones on either side) are powered by motors. • Turn the wheels and you will feel the resistance of the motors. • The third wheel is a free wheel that is there for support only. • All the movements the Scribbler performs are controlled through the two motor-driven wheels. • The command that directly controls the two motors is the motors command: >>> motors(LEFT, RIGHT) • LEFT and RIGHT can be any value in the range [-1.0...1.0] and these values control the left and right motors, respectively. Specifying a negative value moves the motors/wheels backwards and positive values move it forward. >>> motors(1.0, 1.0) • will cause the robot to move forward at full speed, and the command: >>> motors(0.0, 1.0) • will cause the left motor to stop and the right motor to move forward at full speed resulting in the robot turning left. Thus by giving a combination of left and right motor values, you can control the robot's movements.

12. Move and Turn… • There is also the move command: >>> move(TRANSLATE_SPEED, ROTATE_SPEED) • In all of these commands, SPEED can be a value between [-1.0...1.0]. • You can probably tell from the above list that there are a number of redundant commands • You can pick and choose the set of movement commands that appear most convenient to you.

13. Play! • Move your robot around – make a plan in your head and see if you can navigate your robot from place to place. What can you make him do?