🔰 First Time with Arduino: Start from Zero

This page is for people who have never written code. Follow it once, in about 15 minutes, and you will connect an MBC sensor to an Arduino and see the sensor's numbers on your computer. Every product's examples work the same way after that.

Tip

If a word is new to you, skip it and just follow the steps. After doing it once, it will make sense.

What You Need

Item Notes
Arduino UNO (or Nano) The most common Arduino board. Mega, UNO R4 and ESP32 also work; see the pin table below
USB cable UNO uses a "square" (USB-B) cable; Nano uses Mini USB or Type-C, depending on the board. It must be a data cable: some cheap cables can only charge
Computer Windows or Mac
MBC sensor (Universal I2C edition) Comes with a 4-wire cable

Step 1: Install the Arduino IDE

The Arduino IDE is free software for writing programs and sending them to the Arduino.

  1. Download it from the official site: https://www.arduino.cc/en/software. Choose your computer system (on Windows, choose Windows Win 10 and newer).
  2. The download page asks if you want to donate. Click JUST DOWNLOAD to download right away.
  3. During setup, click Next each time. If it asks to install drivers, click Install every time.
  4. Open the Arduino IDE. The menus are in English. To change the language: File → Preferences → Language, then click OK and restart.

Step 2: Connect the Arduino with the USB Cable

  1. Connect the Arduino to the computer with the USB cable. A light on the board turns on.
  2. In the drop-down menu at the top of the Arduino IDE (Select Board), choose your board, for example Arduino Uno. The port name is shown next to it, such as COM3 (on a Mac: /dev/cu.usb…). You can also use Tools → Board and Tools → Port.

Warning

Can't find your board in the menu? There are two common reasons:

  1. The USB cable can only charge and cannot send data → try a different cable.
  2. Your board is a compatible board (the USB chip on the board says CH340) → install the CH340 driver first (search for "CH340 driver", download and install it). Then unplug the USB cable and plug it in again.

Step 3: Connect the MBC Sensor

MBC Universal I2C sensors use only 4 wires: two for power (VCC, GND) and two for signals (SDA, SCL).

Label on the sensor Arduino UNO / Nano Arduino Mega UNO R4 ESP32
VCC (or 5V) 5V 5V 5V 5V (the pin labeled VIN or 5V)
GND GND GND GND GND
SDA A4 20 A4 GPIO 21
SCL A5 21 A5 GPIO 22

Important

  • Unplug the USB cable before wiring. Connect the wires, check them once, then plug the USB cable back in.
  • On the UNO, near the USB connector, the top two pins without numbers are also labeled SDA, SCL. They are the same as A4 and A5, so you can use either.
  • The connector order is a little different on each product. Always follow the labels printed on the sensor board.

Step 4: Send the Example Program to the Arduino

  1. On the product's examples page, click Copy at the top right of the code box, or download the .ino file.
  2. In the Arduino IDE: File → New Sketch. Delete everything in the new window, then paste the code you copied.
  3. Click the → (Upload) button at the top left. The first time, it asks where to save. Give it any name and save it.
  4. When you see "Done uploading" at the bottom, it worked.

Tip

Upload failed with red text? The most common reason is the wrong board or port. Go back to Step 2 and choose them again.

Step 5: Open the Serial Monitor to See the Numbers

The Arduino has no screen. The examples "print" what the sensor reads to your computer.

  1. Click the magnifying glass icon (Serial Monitor) at the top right of the Arduino IDE. You can also use Tools → Serial Monitor.
  2. In the speed menu on the right side of the bottom window, choose 115200 baud (every MBC example uses this speed).
  3. You should see the example's text and numbers updating again and again.

Warning

Seeing strange symbols? The speed is not 115200. Change it and it will look normal.

Keeps saying the sensor is not found? Check the 4 wires from Step 3: are SDA and SCL swapped? Are VCC and GND firmly plugged in?

What Do the Symbols in the Code Mean?

Every line in the examples has an English note. Knowing these few is enough to start:

What you see Meaning
Words after // A note for people to read. The Arduino does not run it
void setup() { … } Things done only once at power-on (for example: get the sensor ready)
void loop() { … } Things done again and again (for example: keep reading the sensor)
delay(500); Wait a moment. The unit is milliseconds: 500 = 0.5 seconds
Serial.println(…); Print something to the Serial Monitor, then start a new line
if (…) { … } "If" the thing in the round brackets is true, do the things in the curly brackets
Things like int distance = …; Make a "box" (a variable) named distance to store a number, so you can use it later. Box names can only use English letters and numbers

Tip

Numbers marked "👉 You can change this" in the examples are safe to change. Change one, click Upload again, and see what is different.

Arduino Examples for Each Product

Product Examples page
Pathfinder 8-Way Arduino Examples
Pathfinder 16-Way Arduino Examples
Ranger 8-Way Arduino Examples
Ranger 2-Way (new version coming soon) Arduino Examples
Controller 2.4G (PS2, Taiwan only) Arduino Examples
Controller PS4/PS5 Arduino Examples
IMU Gyro Arduino Examples
MBC EXP6 6-Port Motor Expander (for LEGO® SPIKE™) Arduino Examples (this one connects over serial, not like Step 3 above; see its examples page)

Want the communication rules shared by every MBC product (for people who can code)? See the MBC Universal I2C Protocol.

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