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Module 1 · Learning to Drive

Lesson 1 · Meet the XRP — Knowledge ChecksAnswer key

Correct answers are marked and the explanation follows each question.

  1. Why does the XRP have two motors instead of just one?

    1. A.So it can carry heavier loads
    2. B.So each side can move at a different speed, which lets the robot steer✓
    3. C.So there is a spare motor in case one fails
    4. D.One motor drives, the other only brakes

    Two independently driven wheels are what let a differential-drive robot turn — speed up one side to curve toward the other.

  2. Which part is the 'brain' that runs your program and tells the motors what to do?

    1. A.The battery
    2. B.The reflectance sensor
    3. C.The controller board✓
    4. D.The caster wheel

    The controller board receives your uploaded program and drives everything else.

  3. Your robot is brand new. Why can't you just connect to it over Bluetooth right away?

    1. A.Bluetooth only works with Python, not Blockly
    2. B.It has to be connected by USB once first, so XRP Code can set up the software on the robot✓
    3. C.Bluetooth is slower, so uploads would fail
    4. D.You can — Bluetooth always works out of the box

    The first USB connection is what lets XRP Code install and update the robot's MicroPython software. After that, the same robot can connect wirelessly.

  4. A classmate built a program in XRP Code on Safari, but when they click CONNECT their robot never appears in the list. What is the most likely reason?

    1. A.The robot is broken
    2. B.Safari cannot connect to the robot — XRP Code needs Chrome or Edge for that✓
    3. C.The program has too many blocks
    4. D.They need to create an account first

    Building a program works in any browser; connecting to the robot does not. The serial and Bluetooth features XRP Code uses exist only in Chrome and Edge, so the robot never shows up in the list.

  5. You place two Straight blocks one above the other. When you run the program, what happens?

    1. A.Both blocks run at the same time
    2. B.The blocks run in order — the first finishes, then the second starts✓
    3. C.Only the top block runs
    4. D.The robot picks one block at random

    Blocks execute in sequence, top to bottom — one command finishes before the next begins.

  6. True or false: you can run a program on the robot without uploading it.

    1. A.True
    2. B.False — the program must be uploaded over USB before the robot can run it✓

    Blockly is just the editor. Uploading is what puts runnable code on the robot.

  7. True or false: the reflectance sensors detect color.

    1. A.True
    2. B.False — they detect light vs. dark (like a white floor vs. a black line), not color✓

    Reflectance sensors measure how much light bounces back, so they read light/dark — not specific colors.