First Drive — Starter Code

This folder holds the starter program for Day 1: First Drive.

  • drive_square.py — the starter you’ll edit and calibrate today
  • solution/drive_square.py — instructor reference (a complete, calibrated example)

How to run it

  1. On a Windows laptop or Chromebook, open Chrome, Edge, or Chromium and go to code.pybricks.com. (Web Bluetooth is required — iPads, iPhones, and Firefox will not connect.)
  2. Turn on your hub. Click the Bluetooth / connect button and pick your hub’s name from the list (your hub has a name and a matching label).
  3. Make a new program and paste in drive_square.py (or build the same thing with blocks — see the Block Coding Guide).
  4. Click Run. Watch what the robot actually does.

Before you trust the numbers — calibrate!

The drive_square.py starter contains starting guesses, not correct answers:

robot = DriveBase(left, right, wheel_diameter=56, axle_track=112)

Every robot is a little different. You’ll measure and adjust these today:

  • Run robot.straight(1000) and measure how far it really went → adjust wheel_diameter
  • Run robot.turn(360) and see if it spins exactly once → adjust axle_track

Record your measured values on the worksheet.

Quick troubleshooting

  • Robot drives backward? Flip a motor’s Direction (CLOCKWISE ↔ COUNTERCLOCKWISE). This depends on how the motors are mounted — it’s normal tuning, not a broken robot.
  • Turns the wrong way? turn() is positive = clockwise / right, negative = left. Check the sign of your number.
  • Hub not in the Bluetooth list? Make sure it’s on and not already connected to another laptop (only one connection at a time), then refresh the page.