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Overview

This page provides a complete component list for building the autonomous Mecanum wheel robot, including specifications, approximate costs, and sourcing information.
Total Cost: Approximately $600-800 USD depending on component choices and availability.

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Complete Bill of Materials (BOM)

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Core Electronics

ComponentSpecificationQuantityUnit PriceTotalNotes
Raspberry Pi 54GB or 8GB RAM1$60-80$60-808GB recommended for Nav2
ESP32-WROOM-32DevKit V1 or similar1$5-10$5-10Any ESP32 board works
RPLIDAR A1M8360° 2D LiDAR scanner1$99$99Essential for navigation
ICM-20948 IMU9-axis (accel, gyro, mag)1$15-20$15-20Breakout board with I2C
microSD Card64GB UHS-I Class 101$10-15$10-15For Raspberry Pi OS
Subtotal: $189-224

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Motors & Drivers

ComponentSpecificationQuantityUnit PriceTotalNotes
DC Motors12V 333RPM with encoder4$15-20$60-80JGA25-370 or similar
Motor DriversIBT-2 (BTS7960) 43A H-bridge2$5-10$10-20Controls 2 motors each
Mecanum Wheels60mm diameter4$8-12$32-48Aluminum hub preferred
Motor MountsAluminum L-bracket4$2-3$8-123D printed alternative OK
Subtotal: $110-160

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Power System

ComponentSpecificationQuantityUnit PriceTotalNotes
LiPo Battery3S (11.1V) 5000mAh 30C1$35-50$35-50Or 10000mAh for longer runtime
Buck Converter12V → 5V 5A1$5-8$5-8For Raspberry Pi power
Voltage RegulatorLM2596 or similar1$3-5$3-5Additional 5V rail if needed
Power SwitchRocker switch 10A rated1$2-3$2-3Main power on/off
XT60 ConnectorBattery connector2$1-2$2-4Male + female
Emergency StopPush-button NC switch1$5-10$5-10Safety critical
LiPo ChargerBalance charger1$20-40$20-40For 3S LiPo
Subtotal: $72-120

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Mechanical Structure

ComponentSpecificationQuantityUnit PriceTotalNotes
Chassis BaseAcrylic/aluminum 40×30cm1$15-25$15-25Or 3D printed parts
Mounting PlateAcrylic 30×20cm1$8-12$8-12For electronics
StandoffsM3 30mm brass8-12$0.50$4-6Multi-tier mounting
Screws/NutsM3 assortment50+-$5-10Various lengths
Cable TiesVarious sizes20+-$3-5Cable management
Subtotal: $35-58

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Wiring & Connectors

ComponentSpecificationQuantityTotalNotes
Jumper WiresMale-Female, Male-Male40+$5-8Various lengths
JST Connectors2-pin, 3-pin, 4-pin10+$5-10Motor and sensor connections
Heat ShrinkAssorted sizes-$5-8Wire insulation
Wire22 AWG, 18 AWG5m each$10-15Power and signal wires
USB CablesUSB-C, Micro-USB, Type-A3+$10-15Pi power, ESP32, LiDAR
BreadboardFull size or half size1$5-8Prototyping connections
Subtotal: $40-64

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Optional Components

ComponentPurposePricePriority
Raspberry Pi Camera v2/v3Visual feedback, SLAM$25-35Low
Voltage/Current SensorBattery monitoring$5-10Medium
LED IndicatorsStatus lights$5Low
BuzzerAudio feedback$3Low
Cooling FanRaspberry Pi cooling$5-8Medium
HeatsinksESP32, Pi components$5-10Medium
GPS ModuleOutdoor navigation$15-25Low
Optional Subtotal: $68-111

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Total Cost Breakdown

CategoryMinimumRecommendedMaximum
Core Electronics$189$210$224
Motors & Drivers$110$130$160
Power System$72$95$120
Mechanical$35$45$58
Wiring$40$50$64
Core Total$446$530$626
Optional Components$0$40$111
Grand Total$446$570$737
Budget Tip: Start with minimum configuration. Add optional components later as needed. Used or surplus components can reduce costs significantly.

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Component Details

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Raspberry Pi 5 vs. 4

Recommended: Raspberry Pi 5
FeaturePi 4 (4GB)Pi 5 (4GB)Pi 5 (8GB)
CPU1.5GHz quad-core2.4GHz quad-core2.4GHz quad-core
RAM4GB LPDDR44GB LPDDR4X8GB LPDDR4X
USB2× USB 3.0, 2× USB 2.02× USB 3.0, 2× USB 2.02× USB 3.0, 2× USB 2.0
PerformanceBaseline2-3× faster2-3× faster
Nav2 PerformanceOK (may lag)GoodExcellent
Price$55$60$80
Verdict: Pi 5 4GB sufficient for basic nav, 8GB recommended for advanced features (camera, SLAM). Alternative: Raspberry Pi 4 (4GB) works but may be slower with Nav2.

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ESP32 Variants

Any ESP32-WROOM-32 board works:
BoardGPIO PinsFlashRAMPriceNotes
ESP32 DevKit V1304MB520KB$5-8Most common
ESP32-WROOM-32D304MB520KB$6-10Newer version
ESP32-S3368MB512KB$10-15Faster, more memory
Verdict: Standard ESP32 DevKit V1 is sufficient. More expensive variants offer no significant benefit for this project.

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Motor Options

Recommended: JGA25-370 12V 333RPM with encoder
SpecificationValueNotes
Voltage12V DCNominal
RPM333 (no load)With 1:19 gearbox
Torque0.8 - 1.0 Nm (stall)Sufficient for robot
EncoderHall effect, quadrature11 PPR (motor) = 209 PPR (output)
Current0.5-1.0A (loaded)Peak 2-3A
Weight~100gPer motor
Alternatives:
  • Lower RPM (200-250 RPM): More torque, slower robot
  • Higher RPM (500-600 RPM): Less torque, faster robot
Key consideration: Match motor voltage to battery (12V motors with 3S LiPo).

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Mecanum Wheel Specifications

Recommended: 60mm diameter aluminum hub wheels
ParameterValueNotes
Diameter60-80mm60mm most common
MaterialAluminum hub, rubber rollersDurable
Roller Angle45°Standard Mecanum
Shaft4mm or 6mm boreMatch motor shaft
Weight50-80gPer wheel
Left vs. Right wheels:
  • Need 2× left-handed wheels
  • Need 2× right-handed wheels
  • Orientation: Rollers form ‘X’ pattern when viewed from above
Check: Wheel shaft bore matches motor shaft diameter (most JGA25-370 use 4mm or 6mm).

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LiDAR: RPLIDAR A1M8

Specifications:
ParameterValue
Range0.15m - 12m
Angular Resolution1° (360 points/scan)
Scan Rate5.5 Hz
Sample Rate8000 samples/sec
InterfaceUSB (UART internally)
Power5V, ~500mA
Weight160g
Why RPLIDAR A1M8:
  • Affordable (99vs.99 vs. 400+ for alternatives)
  • Well-supported in ROS2 (rplidar_ros package)
  • Reliable and proven
  • Perfect for indoor navigation
Alternatives:
  • RPLIDAR A2M8: Faster scan rate (10 Hz), double price
  • YDLiDAR X4: Cheaper ($70), lower quality
  • Slamtec RPLIDAR A3: Longer range (25m), $300+

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IMU: ICM-20948

Specifications:
SensorRangeResolution
Gyroscope±2000°/s16-bit
Accelerometer±16g16-bit
Magnetometer±4900µT16-bit
InterfaceI2C, SPII2C recommended
Power3.3V, ~5mA
Why ICM-20948:
  • 9-axis (gyro + accel + mag) for full orientation
  • Industry-standard (TDK InvenSense)
  • Arduino/CircuitPython libraries available
  • Small breakout boards available
Alternatives:
  • MPU-9250: Older version, similar capability
  • BNO085: Better sensor fusion, more expensive
  • LSM9DS1: Similar specs, different manufacturer

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Sourcing Recommendations

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Online Retailers

Electronics:
  • AliExpress: Cheapest, long shipping (2-4 weeks)
  • Amazon: Fast shipping, slightly higher cost
  • DigiKey/Mouser: Reliable, fast, higher prices
  • Adafruit/SparkFun: Quality breakout boards, tutorials
Mechanical:
  • McMaster-Carr: Excellent selection, fast shipping (US)
  • Local hardware store: Screws, standoffs, acrylic sheets
  • 3D printing services: Custom brackets and mounts

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Budget Optimization

Ways to reduce cost:
  1. Use existing components:
    • Old laptop as development PC
    • Spare USB cables
    • Recycled enclosure/chassis
  2. Salvage parts:
    • Motors from old toys
    • Wheels from old RC cars
    • Power supplies from electronics
  3. 3D printing:
    • Print wheels (if no Mecanum wheels available)
    • Print motor mounts
    • Print enclosures
  4. Buy in bulk/group orders:
    • Share shipping costs with classmates
    • Bulk discounts on components
  5. Buy used:
    • eBay, Facebook Marketplace
    • University surplus sales
    • Maker spaces

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Safety Components (Critical)

Never skip safety components! Emergency stop and proper fusing prevent fires and injuries.
Required safety items:
  1. Emergency Stop Button:
    • Normally-closed (NC) contact
    • Interrupts motor power
    • Easily accessible
    • Price: $5-10
  2. Fuse:
    • 10A fast-blow for 3S LiPo
    • Protects against short circuits
    • Place near battery positive
    • Price: $2-5 (pack of 10)
  3. LiPo Safety Bag:
    • Fire-resistant storage
    • For charging and storage
    • Essential for safety
    • Price: $10-15
  4. LiPo Alarm/Voltage Monitor:
    • Warns of low voltage
    • Prevents over-discharge (< 3.0V/cell)
    • Extends battery life
    • Price: $3-5

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Tools Required

Basic tools needed:
ToolPurposePrice
Soldering IronSolder connections$15-30
MultimeterVoltage/current measurement$10-20
Screwdriver SetPhillips, flathead$10-15
Wire StripperStrip wire insulation$10-15
Hex Key SetM3 screws$5-10
Hot Glue GunSecure components$5-10
DrillMounting holes$20-50 (or borrow)
Total tool cost: $75-150 (one-time investment)

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Next Steps

ESP32 Details

Complete ESP32 specifications and pinout

Raspberry Pi Details

Raspberry Pi specifications and setup

Motor Specifications

DC motor datasheets and wiring

LiDAR Specifications

RPLIDAR A1M8 complete specs

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References

[1] Raspberry Pi Official: https://www.raspberrypi.com/products/ [2] ESP32 Datasheet: https://www.espressif.com/sites/default/files/documentation/esp32_datasheet_en.pdf [3] RPLIDAR A1 Specs: https://www.slamtec.com/en/Lidar/A1Spec [4] ICM-20948 Datasheet: https://invensense.tdk.com/products/motion-tracking/9-axis/icm-20948/