Build Instructions

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• 1

  PlanetX Sensors

  Before we start building anything, let’s talk about the sensors — because honestly, this is what makes this kit special. The ELECFREAKS Nezha Pro AI Mechanical Power Kit comes with 8 PlanetX sensors, all designed to be plug-and-play using RJ11 connectors. No soldering, no complex wiring — just connect them to the correct port, and you’re ready to go.

  🤚 Gesture Sensor

  This sensor can recognize 9 different hand gestures — up, down, left, right, forward, backward, clockwise, counterclockwise, and wave. It works using infrared light. The sensor continuously emits IR signals, and as your hand moves in front of it, the reflected light pattern changes. An onboard processor analyzes these changes and converts them into gesture data. For best results, keep your hand about 5–15 cm away. Too close can overwhelm the sensor, and too far reduces accuracy.

  🎙️ Speech Recognition Sensor

  This is one of the most impressive modules in the kit. It performs offline voice recognition, meaning everything runs directly on the sensor — no internet required. It comes preloaded with 21 English commands such as “full speed ahead,” “turn left,” and “avoid object.” The sensor analyzes your voice, converts it into frequency patterns, and matches it with stored templates.

  For best performance:

  1. Speak clearly
  2. Stay within ~50 cm
  3. Avoid noisy environments

  📡 Ultrasonic Sensor

  This sensor measures distance using sound waves, similar to how bats navigate. It emits a 40 kHz ultrasonic pulse and measures how long it takes for the echo to return. From this, it calculates distance using:

  Distance = (Echo Time × Speed of Sound) ÷ 2

  It can detect objects from about 2 cm to 4 meters, making it perfect for obstacle avoidance.

  ⬛ Line Tracking Sensor

  This sensor uses infrared light to detect surface contrast.

  1. White surfaces reflect more IR → high signal
  2. Black surfaces absorb IR → low signal

  By comparing left and right readings, the robot can detect its position relative to a line and continuously adjust its movement. This process happens rapidly, allowing smooth and accurate line following.

  💥 Crash Sensor

  A simple but practical sensor — essentially a mechanical switch. When the robot physically bumps into something, the sensor is triggered and sends a signal. It works well as a backup safety system or as a trigger for specific actions.

  🌈 LED Rainbow

  An RGB LED ring that can display multiple colors and animations.

  You can use it to:

  1. Indicate sensor states
  2. Create visual effects
  3. Build interactive lighting systems

  🖥️ OLED Display

  A small screen used to display real-time data such as:

  1. Sensor readings
  2. Commands
  3. Debug information

  While not used in the default builds, it’s extremely useful for understanding and debugging your system.

  💨 Motor Fan

  A simple actuator used to demonstrate output control. It responds to commands (like voice input) and is a great example of how sensors can control real-world devices — similar to smart home systems.

  Now that you understand how each sensor works, we’re ready to move on to the fun part — building. We’ll start with a simple gesture-controlled robot, then move into voice control, and finally combine multiple sensors into a fully interactive system.

• 2

  The Nezha Pro Board

  Now that you understand the sensors, there’s one more important piece before we start building — the board that connects everything together. Meet the Nezha Pro Expansion Board. Think of it like this that the micro:bit is the brain — it runs your code and makes decisions & the Nezha Pro board is the control center — it powers motors, connects sensors, and manages everything safely

  The micro:bit alone can’t drive motors or handle multiple sensors efficiently. This board sits in between and makes the entire system work smoothly. Every build in this project depends on it — so understanding it now will save you a lot of confusion later. At first glance, the board might look confusing — lots of ports, lots of labels. But once you break it down, it’s actually very simple.

  Motor Ports (M1, M2, M3, M4)

  These ports are used to connect motors. Whenever your code says something like “run motor M1 at 50% speed”, this is where that command is sent. The connectors are RJ11 type, so they snap in easily and can’t be inserted incorrectly.

  IIC Port (I2C Communication)

  This is used for smart sensors like: Gesture sensor, Voice recognition modul, etc. IIC allows multiple devices to share the same communication line, so you don’t need separate ports for each advanced sensor. In this project, whenever you see “connect to IIC” — this is the port.

  J1 & J2 Ports

  These are for simpler sensors that use basic signals.

  1. J1 → Line tracking sensor
  2. J2 → Ultrasonic sensor

  A simple way to remember:

  1. Smart sensors → IIC
  2. Basic sensors → J1 / J2

  Type-C Port

  Used for charging the onboard battery. The LED indicators show battery level while charging or in use.

  1. Full charge: ~50 minutes
  2. Runtime: ~4 hour

  Color-Coded System (Super Helpful for Beginners)

  One feature I really like is the color-matching system. Each port on the board has a specific color, and every cable matches that color. So instead of guessing, you just match colors and plug in. It might seem like a small detail — but when you’re building with multiple wires, it makes a huge difference.

• 3

  Setting Up MakeCode

  Now that the hardware is ready, it’s time to make everything work — and that’s where coding comes in. Don’t worry if you’ve never programmed before. We’ll be using MakeCode, which is super beginner-friendly. It’s all drag-and-drop blocks, so you don’t have to write complicated code. MakeCode is a free online platform made for the micro:bit. You just open it in your browser, drag blocks together, and your program is ready. It even has a simulator on the screen, so you can test your code before uploading it.

  Getting Started

  1. Go to makecode.microbit.org
  2. Click New Project
  3. Give it a name like GestureCar or VoiceTruck
  4. Click Create

  Add Extensions

  To use this kit, we need to add two extensions.

  1. Click Extensions (bottom of blocks list)
  2. Search Nezha Pro → install it
  3. Go back and search PlanetX → install it

  Now you’ll see new blocks for motors and sensors. Without this step, you won’t find the right controls.

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