🤖 Arduino Robot Assembly Guide

Visual Step-by-Step Instructions with Diagrams

📦 PHASE 1: Chassis & Motor Assembly (2-3 hours)
1

Prepare Chassis Frame

Start with a clean, flat surface. Inspect your robot chassis for any defects or sharp edges that could damage components.

Components Needed:

  • Robot chassis (170×140mm aluminum frame)
  • Two DC gear motors (200RPM)
  • Metal L-brackets (4x)
  • M3 screws and bolts
  • Small wrench set or screwdriver
✓ Check: Chassis has 4 motor mounting holes and is free from damage.
CHASSIS (170×140mm) Motor Mounting Holes 300mm
2

Mount DC Motors

Attach the left motor to the front-left position and right motor to front-right position using metal L-brackets and M3 screws.

Mounting Details:

  • Use M3 × 10mm screws for bracket attachment
  • Motor shaft must point DOWNWARD (toward the ground)
  • Ensure motors are parallel to each other
  • Motors should be flush with the chassis edge
  • Tighten screws firmly but don't over-torque
⚠️ Critical: If motors are not parallel, robot will curve to one side. Adjust brackets if needed.
MOTOR LEFT Shaft MOTOR RIGHT Shaft Shafts must be PARALLEL ❌ WRONG if motor shafts angle differently
3

Install Wheels on Motors

Slide the wheels onto the motor shafts using the wheel couplings. Ensure wheels are centered and tightened securely.

Installation Process:

  • Insert motor shaft into the wheel coupling center hole
  • Push wheel all the way onto the motor shaft
  • Align the set screw hole with the flat portion of the shaft
  • Tighten set screw (M2.5) until snug (DO NOT over-tighten)
  • Manually rotate wheel to verify smooth, wobble-free motion
💡 Tip: Wheels should spin freely for at least 10 complete rotations without stopping. If sticky, clean the motor shaft.
SIDE VIEW: Motor with Wheel DC Motor COUP WHEEL Assembly Steps: 1. Align wheel coupling with motor shaft 2. Push wheel onto shaft firmly 3. Tighten set screw until snug
🔋 PHASE 2: Power System Installation (1-2 hours)
4

Mount Battery Pack

Install the 7.4V lithium battery pack on the chassis bottom, centered for weight balance.

Installation:

  • Place battery horizontally on chassis bottom
  • Use Velcro strips (NOT glue) for easy removal
  • Center the battery between front and rear wheels
  • Leave 2cm clearance from edges for balance
  • Secure JST connector loosely (don't connect yet)
⚠️ Safety: Do NOT connect battery to circuit until ALL wiring is complete and verified.
CHASSIS - BOTTOM VIEW + - 7.4V Li-ion Battery Pack Balanced weight distribution
5

Install ON/OFF Power Switch

Connect the slide switch in series with the battery positive line for safe power control.

Wiring Connection:

  • Battery + → Slide Switch IN
  • Slide Switch OUT → L298N +12V & Arduino 5V input
  • Battery GND → Arduino GND & L298N GND (common ground)
  • Mount switch on chassis side for easy access
  • Label switch positions: ON (right) / OFF (left)
✓ Verify: Switch is accessible and clearly labeled. No exposed terminals.
Power Switch Circuit + - 7.4V SWITCH ON/OFF L298N +Positive Common Ground
🎛️ PHASE 3: Control Board Installation (1.5 hours)
6

Mount Arduino & Motor Driver

Install control boards on chassis top in organized layout for easy programming access and signal integrity.

Positioning:

  • Arduino Uno: Center-front position (USB accessible)
  • L298N: Center-rear position (near motors)
  • Use Velcro strips for non-permanent mounting
  • Leave 2-3cm spacing between boards for airflow
  • Ensure heat sink on L298N has airflow
💡 Tip: Mount Arduino with USB port facing rear for easy access. L298N should be centered for balanced cable routes.
CHASSIS - TOP VIEW Arduino Uno USB L298N Driver 2-3cm space Signal Wires Velcro mounting on chassis top Ensure USB port is accessible Heat sink faces upward for cooling
📡 PHASE 4: Sensor Installation (1.5-2 hours)
7

Mount Line Sensors Underneath

Install the two IR line sensors on the chassis bottom in precisely controlled positions for accurate line detection.

Critical Parameters:

  • Height: Exactly 1.5-2cm above ground level
  • Spacing: 4-5cm apart (left to right)
  • Alignment: Both sensors parallel to ground
  • Position: Front-bottom of chassis
  • Use adjustable brackets for height fine-tuning
⚠️ Critical: Sensor height is THE most important parameter. Test and adjust before final mounting!
SIDE VIEW: Sensor Height Ground / Test Track CHASSIS Sensor 1 Sensor 2 1.5-2cm 4-5cm spacing
8

Mount Servo & Ultrasonic Sensor

Install the SG90 servo motor with HC-SR04 ultrasonic sensor bracket to create a rotating radar head.

Assembly:

  • Secure servo motor on chassis top-center using servo bracket
  • Attach sensor bracket arm to servo motor output shaft
  • Mount HC-SR04 on bracket with sensor facing forward
  • Ensure servo can rotate 0-180° without obstructions
  • Test servo rotation before final mounting
💡 Tip: Route servo and sensor wires along the arm using hot glue to prevent tangling during rotation.
TOP VIEW: Servo & Ultrasonic Sensor Servo HC-SR04 0° to 180° Rotation 90°

⏱️ Complete Assembly Timeline

Phase 1
2-3h

Chassis & Motors

Phase 2
1-2h

Power System

Phase 3
1.5h

Control Boards

Phase 4
1.5-2h

Sensors

Testing & Calibration
2-3h

Full Integration

TOTAL
20-30h

Project Complete

✅ Pre-Power-On Verification Checklist

Mechanical Assembly:

Electrical Connections:

Safety Checks:

🎉 All checks passed? You're ready to proceed to the Electrical Testing & Programming Phase!