nfrax - Infrastructure that just works

This guide covers complete hardware setup for robo-infra, from initial Raspberry Pi configuration to connecting servos, motors, and sensors.

Overview

robo-infra supports multiple hardware platforms. This guide focuses on the most common setup:

Raspberry Pi 4/5 as the main controller
PCA9685 16-channel PWM driver for servos
MPU6050 IMU for motion sensing
L298N H-bridge for DC motors

For other platforms, see Platform Support.

Part 1: Raspberry Pi Setup

1.1 Operating System

Install Raspberry Pi OS (64-bit recommended):

bash

# Using Raspberry Pi Imager
# Select: Raspberry Pi OS (64-bit)
# Enable SSH, set hostname, configure WiFi

1.2 Enable Hardware Interfaces

bash

# Open raspi-config
sudo raspi-config

# Enable I2C (for PCA9685, MPU6050, sensors)
# Navigate: Interface Options -> I2C -> Enable

# Enable SPI (for high-speed devices)
# Navigate: Interface Options -> SPI -> Enable

# Enable Serial/UART (for GPS, LiDAR)
# Navigate: Interface Options -> Serial Port -> Enable

# Reboot to apply changes
sudo reboot

1.3 Verify I2C

bash

# Install I2C tools
sudo apt-get update
sudo apt-get install -y i2c-tools python3-smbus

# Scan for devices (should show nothing if no devices connected)
i2cdetect -y 1

# Expected output with PCA9685 (0x40) and MPU6050 (0x68):
#      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
# 00:          -- -- -- -- -- -- -- -- -- -- -- -- --
# 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
# 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
# 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
# 40: 40 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
# 50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
# 60: -- -- -- -- -- -- -- -- 68 -- -- -- -- -- -- --
# 70: -- -- -- -- -- -- -- --

1.4 Install robo-infra

bash

# Install Python 3.11+
sudo apt-get install -y python3-pip python3-venv

# Create virtual environment
python3 -m venv ~/robo-env
source ~/robo-env/bin/activate

# Install robo-infra with hardware support
pip install robo-infra[hardware]

# Or from source for latest features
git clone https://github.com/nfraxlab/robo-infra.git
cd robo-infra
pip install -e ".[hardware]"

Part 2: Hardware Connections

2.1 PCA9685 PWM Driver

The PCA9685 provides 16 channels of 12-bit PWM, perfect for controlling servos.

Wiring:

Raspberry Pi	PCA9685	Description
Pin 1 (3.3V)	VCC	Logic power
Pin 3 (GPIO2/SDA)	SDA	I2C data
Pin 5 (GPIO3/SCL)	SCL	I2C clock
Pin 6 (GND)	GND	Ground
External 5-6V	V+	Servo power

Important Notes:

V+ is separate from VCC - this powers the servos
Use a 5-6V power supply rated for your servo count
Each servo draws ~200-500mA, plan accordingly
Add a large capacitor (1000µF) across V+ and GND for stability

Verify Connection:

bash

# PCA9685 should appear at address 0x40
i2cdetect -y 1

# Test with Python
python3 -c "from robo_infra.platforms import get_i2c; print(get_i2c().scan())"
# Expected: [64] (0x40 = 64 decimal)

2.2 Servo Motors

Connect servos to PCA9685 channels:

Servo Wire	PCA9685 Pin
Signal (Orange/Yellow)	PWM (top row)
Power (Red)	V+ (middle row)
Ground (Brown/Black)	GND (bottom row)

Standard Servo Mapping:

Channel	Common Use	Pulse Range
0	Base rotation	500-2500µs
1	Shoulder	500-2500µs
2	Elbow	500-2500µs
3	Wrist pitch	500-2500µs
4	Wrist roll	500-2500µs
5	Gripper	500-2500µs

Test Servo:

python

from robo_infra.platforms import get_i2c
from robo_infra.drivers import PCA9685Driver
from robo_infra.actuators import Servo

# Initialize
i2c = get_i2c(bus=1)
driver = PCA9685Driver(i2c_bus=i2c, frequency=50)

# Create and test servo
servo = Servo(name="test", driver=driver, channel=0)
await servo.move_to(90)  # Center position

2.3 MPU6050 IMU

The MPU6050 provides 6-axis motion sensing (accelerometer + gyroscope).

Wiring:

Raspberry Pi	MPU6050	Description
Pin 1 (3.3V)	VCC	Power
Pin 3 (GPIO2/SDA)	SDA	I2C data
Pin 5 (GPIO3/SCL)	SCL	I2C clock
Pin 6 (GND)	GND	Ground
Pin 6 (GND)	AD0	Address select (0x68)

Address Configuration:

AD0 -> GND: Address 0x68 (default)
AD0 -> VCC: Address 0x69

Verify Connection:

bash

# MPU6050 should appear at address 0x68
i2cdetect -y 1

# Test with Python
python3 -c "
from robo_infra.platforms import get_i2c
i2c = get_i2c()
i2c.write_byte(0x68, 0x6B)  # Power management register
print('MPU6050 connected!')
"

2.4 DC Motors with L298N

The L298N H-bridge controls two DC motors with direction and speed.

Wiring:

Raspberry Pi	L298N	Description
GPIO18 (PWM)	ENA	Motor A speed
GPIO23	IN1	Motor A direction
GPIO24	IN2	Motor A direction
GPIO19 (PWM)	ENB	Motor B speed
GPIO25	IN3	Motor B direction
GPIO26	IN4	Motor B direction
Pin 6 (GND)	GND	Common ground

Motor Power:

Connect motor power (6-12V) to 12V and GND terminals
Remove 5V jumper if using >12V external power
Connect motors to OUT1/OUT2 and OUT3/OUT4

Test Motor:

python

from robo_infra.platforms import get_gpio, get_pwm
from robo_infra.core.pin import PinMode

# Setup pins
enable = get_gpio(18, mode=PinMode.PWM, frequency=1000)
in1 = get_gpio(23, mode=PinMode.OUTPUT)
in2 = get_gpio(24, mode=PinMode.OUTPUT)

# Forward at 50% speed
in1.high()
in2.low()
enable.duty_cycle = 50

# Reverse
in1.low()
in2.high()

# Stop
enable.duty_cycle = 0

Part 3: Common Hardware Setups

3.1 Robot Arm (6-DOF)

Complete 6-axis robot arm with gripper:

code

Raspberry Pi 4
    │
    └── I2C Bus 1
          │
          └── PCA9685 (0x40)
                ├── CH0: Base servo (rotation)
                ├── CH1: Shoulder servo
                ├── CH2: Elbow servo
                ├── CH3: Wrist pitch servo
                ├── CH4: Wrist roll servo
                └── CH5: Gripper servo

Code:

python

from robo_infra.platforms import get_i2c
from robo_infra.drivers import PCA9685Driver
from robo_infra.actuators import Servo, ServoGroup
from robo_infra.core.types import Limits

# Initialize hardware
i2c = get_i2c(bus=1)
driver = PCA9685Driver(i2c_bus=i2c, frequency=50)

# Define servos with limits
servos = ServoGroup([
    Servo("base", driver, channel=0, limits=Limits(-90, 90)),
    Servo("shoulder", driver, channel=1, limits=Limits(0, 180)),
    Servo("elbow", driver, channel=2, limits=Limits(0, 135)),
    Servo("wrist_pitch", driver, channel=3, limits=Limits(-90, 90)),
    Servo("wrist_roll", driver, channel=4, limits=Limits(-180, 180)),
    Servo("gripper", driver, channel=5, limits=Limits(0, 45)),
])

# Home position
await servos.home()

# Move to target
await servos.move_to({
    "base": 45,
    "shoulder": 90,
    "elbow": 45,
    "gripper": 30,
})

3.2 Mobile Robot (Differential Drive)

Two-wheel differential drive robot:

code

Raspberry Pi 4
    │
    ├── GPIO (Direct)
    │     ├── GPIO18: Left motor PWM
    │     ├── GPIO23: Left motor IN1
    │     ├── GPIO24: Left motor IN2
    │     ├── GPIO19: Right motor PWM
    │     ├── GPIO25: Right motor IN1
    │     └── GPIO26: Right motor IN2
    │
    └── I2C Bus 1
          └── MPU6050 (0x68) - IMU for orientation

Code:

python

from robo_infra.platforms import get_gpio, get_i2c
from robo_infra.actuators import DCMotor
from robo_infra.sensors import MPU6050
from robo_infra.core.pin import PinMode

# Motor setup
left_motor = DCMotor(
    pwm_pin=get_gpio(18, mode=PinMode.PWM, frequency=1000),
    in1_pin=get_gpio(23),
    in2_pin=get_gpio(24),
)

right_motor = DCMotor(
    pwm_pin=get_gpio(19, mode=PinMode.PWM, frequency=1000),
    in1_pin=get_gpio(25),
    in2_pin=get_gpio(26),
)

# IMU for heading
imu = MPU6050(i2c=get_i2c(bus=1))

# Drive forward
left_motor.forward(speed=0.5)
right_motor.forward(speed=0.5)

# Turn right
left_motor.forward(speed=0.5)
right_motor.backward(speed=0.5)

3.3 Sensor Array

Multiple I2C sensors on same bus:

code

Raspberry Pi 4
    │
    └── I2C Bus 1
          ├── MPU6050 (0x68) - IMU
          ├── BMP280 (0x76)  - Barometer
          ├── HMC5883L (0x1E) - Magnetometer
          └── VL53L0X (0x29) - ToF distance sensor

Code:

python

from robo_infra.platforms import get_i2c

# Single I2C bus, multiple devices
i2c = get_i2c(bus=1)

# Scan for devices
devices = i2c.scan()
print(f"Found {len(devices)} I2C devices: {[hex(d) for d in devices]}")

# Read from each sensor
imu_data = i2c.read_block(0x68, 0x3B, 14)  # MPU6050 accel/gyro
baro_data = i2c.read_block(0x76, 0xF7, 6)  # BMP280 pressure/temp

Part 4: Troubleshooting

4.1 I2C Issues

No devices detected:

bash

# Check I2C is enabled
ls /dev/i2c*
# Should show: /dev/i2c-1

# Check wiring with oscilloscope or logic analyzer
# SDA and SCL should have ~3.3V pull-ups

# Try slower I2C speed
sudo nano /boot/config.txt
# Add: dtparam=i2c_baudrate=50000

Intermittent communication:

bash

# Add external pull-up resistors (4.7kΩ to 3.3V)
# Shorten wires (< 30cm recommended)
# Check power supply is adequate

4.2 Servo Issues

Servo jitter:

python

# Increase PWM frequency precision
driver = PCA9685Driver(i2c_bus=i2c, frequency=50)

# Add decoupling capacitors near servos
# Use separate power supply for servos

Servo not moving:

bash

# Check V+ has power (5-6V)
# Verify correct channel number
# Test with known-good servo

4.3 Power Issues

System unstable when motors run:

bash

# Use separate power supply for motors
# Add large capacitors (1000-4700µF) near motor driver
# Don't power motors from Raspberry Pi 5V

Voltage drops:

bash

# Check power supply capacity
# Each servo: ~200-500mA
# DC motors: ~500mA-2A
# Total capacity should be 2x expected draw

4.4 Permission Issues

bash

# Add user to required groups
sudo usermod -aG gpio,i2c,spi $USER

# Reboot or re-login
sudo reboot

# Verify groups
groups
# Should include: gpio i2c spi

Part 5: Quick Reference

Pin Reference (Raspberry Pi 4/5)

Function	GPIO (BCM)	Pin	Description
I2C SDA	2	3	I2C data
I2C SCL	3	5	I2C clock
SPI MOSI	10	19	SPI data out
SPI MISO	9	21	SPI data in
SPI SCLK	11	23	SPI clock
SPI CE0	8	24	SPI chip select 0
SPI CE1	7	26	SPI chip select 1
PWM0	12, 18	32, 12	Hardware PWM
PWM1	13, 19	33, 35	Hardware PWM
UART TX	14	8	Serial transmit
UART RX	15	10	Serial receive

Common I2C Addresses

Device	Address	Alternate
PCA9685	0x40	0x41-0x7F (configurable)
MPU6050	0x68	0x69 (AD0=VCC)
BMP280	0x76	0x77 (SDO=VCC)
HMC5883L	0x1E	-
VL53L0X	0x29	Programmable
OLED SSD1306	0x3C	0x3D

Voltage Levels

Component	Logic	Power
Raspberry Pi GPIO	3.3V	-
PCA9685	3.3-5V	5-6V (servos)
MPU6050	3.3V	3.3V
L298N	5V	6-12V (motors)
Servos	3.3-5V signal	5-6V
DC Motors	-	6-12V

Next Steps

Hardware Wiring Diagrams - Visual wiring guides
Hardware Testing - Validate your setup
Platform Support - Other platforms
Building a Robot Arm - Complete tutorial

This guide covers complete hardware setup for robo-infra, from initial Raspberry Pi configuration to connecting servos, motors, and sensors.

Overview

robo-infra supports multiple hardware platforms. This guide focuses on the most common setup:

Raspberry Pi 4/5 as the main controller
PCA9685 16-channel PWM driver for servos
MPU6050 IMU for motion sensing
L298N H-bridge for DC motors

For other platforms, see Platform Support.

Part 1: Raspberry Pi Setup

1.1 Operating System

Install Raspberry Pi OS (64-bit recommended):

bash

# Using Raspberry Pi Imager
# Select: Raspberry Pi OS (64-bit)
# Enable SSH, set hostname, configure WiFi

1.2 Enable Hardware Interfaces

bash

# Open raspi-config
sudo raspi-config

# Enable I2C (for PCA9685, MPU6050, sensors)
# Navigate: Interface Options -> I2C -> Enable

# Enable SPI (for high-speed devices)
# Navigate: Interface Options -> SPI -> Enable

# Enable Serial/UART (for GPS, LiDAR)
# Navigate: Interface Options -> Serial Port -> Enable

# Reboot to apply changes
sudo reboot

1.3 Verify I2C

bash

# Install I2C tools
sudo apt-get update
sudo apt-get install -y i2c-tools python3-smbus

# Scan for devices (should show nothing if no devices connected)
i2cdetect -y 1

# Expected output with PCA9685 (0x40) and MPU6050 (0x68):
#      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
# 00:          -- -- -- -- -- -- -- -- -- -- -- -- --
# 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
# 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
# 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
# 40: 40 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
# 50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
# 60: -- -- -- -- -- -- -- -- 68 -- -- -- -- -- -- --
# 70: -- -- -- -- -- -- -- --

1.4 Install robo-infra

bash

# Install Python 3.11+
sudo apt-get install -y python3-pip python3-venv

# Create virtual environment
python3 -m venv ~/robo-env
source ~/robo-env/bin/activate

# Install robo-infra with hardware support
pip install robo-infra[hardware]

# Or from source for latest features
git clone https://github.com/nfraxlab/robo-infra.git
cd robo-infra
pip install -e ".[hardware]"

Part 2: Hardware Connections

2.1 PCA9685 PWM Driver

The PCA9685 provides 16 channels of 12-bit PWM, perfect for controlling servos.

Wiring:

Raspberry Pi	PCA9685	Description
Pin 1 (3.3V)	VCC	Logic power
Pin 3 (GPIO2/SDA)	SDA	I2C data
Pin 5 (GPIO3/SCL)	SCL	I2C clock
Pin 6 (GND)	GND	Ground
External 5-6V	V+	Servo power

Important Notes:

V+ is separate from VCC - this powers the servos
Use a 5-6V power supply rated for your servo count
Each servo draws ~200-500mA, plan accordingly
Add a large capacitor (1000µF) across V+ and GND for stability

Verify Connection:

bash

# PCA9685 should appear at address 0x40
i2cdetect -y 1

# Test with Python
python3 -c "from robo_infra.platforms import get_i2c; print(get_i2c().scan())"
# Expected: [64] (0x40 = 64 decimal)

2.2 Servo Motors

Connect servos to PCA9685 channels:

Servo Wire	PCA9685 Pin
Signal (Orange/Yellow)	PWM (top row)
Power (Red)	V+ (middle row)
Ground (Brown/Black)	GND (bottom row)

Standard Servo Mapping:

Channel	Common Use	Pulse Range
0	Base rotation	500-2500µs
1	Shoulder	500-2500µs
2	Elbow	500-2500µs
3	Wrist pitch	500-2500µs
4	Wrist roll	500-2500µs
5	Gripper	500-2500µs

Test Servo:

python

from robo_infra.platforms import get_i2c
from robo_infra.drivers import PCA9685Driver
from robo_infra.actuators import Servo

# Initialize
i2c = get_i2c(bus=1)
driver = PCA9685Driver(i2c_bus=i2c, frequency=50)

# Create and test servo
servo = Servo(name="test", driver=driver, channel=0)
await servo.move_to(90)  # Center position

2.3 MPU6050 IMU

The MPU6050 provides 6-axis motion sensing (accelerometer + gyroscope).

Wiring:

Raspberry Pi	MPU6050	Description
Pin 1 (3.3V)	VCC	Power
Pin 3 (GPIO2/SDA)	SDA	I2C data
Pin 5 (GPIO3/SCL)	SCL	I2C clock
Pin 6 (GND)	GND	Ground
Pin 6 (GND)	AD0	Address select (0x68)

Address Configuration:

AD0 -> GND: Address 0x68 (default)
AD0 -> VCC: Address 0x69

Verify Connection:

bash

# MPU6050 should appear at address 0x68
i2cdetect -y 1

# Test with Python
python3 -c "
from robo_infra.platforms import get_i2c
i2c = get_i2c()
i2c.write_byte(0x68, 0x6B)  # Power management register
print('MPU6050 connected!')
"

2.4 DC Motors with L298N

The L298N H-bridge controls two DC motors with direction and speed.

Wiring:

Raspberry Pi	L298N	Description
GPIO18 (PWM)	ENA	Motor A speed
GPIO23	IN1	Motor A direction
GPIO24	IN2	Motor A direction
GPIO19 (PWM)	ENB	Motor B speed
GPIO25	IN3	Motor B direction
GPIO26	IN4	Motor B direction
Pin 6 (GND)	GND	Common ground

Motor Power:

Connect motor power (6-12V) to 12V and GND terminals
Remove 5V jumper if using >12V external power
Connect motors to OUT1/OUT2 and OUT3/OUT4

Test Motor:

python

from robo_infra.platforms import get_gpio, get_pwm
from robo_infra.core.pin import PinMode

# Setup pins
enable = get_gpio(18, mode=PinMode.PWM, frequency=1000)
in1 = get_gpio(23, mode=PinMode.OUTPUT)
in2 = get_gpio(24, mode=PinMode.OUTPUT)

# Forward at 50% speed
in1.high()
in2.low()
enable.duty_cycle = 50

# Reverse
in1.low()
in2.high()

# Stop
enable.duty_cycle = 0

Part 3: Common Hardware Setups

3.1 Robot Arm (6-DOF)

Complete 6-axis robot arm with gripper:

code

Raspberry Pi 4
    │
    └── I2C Bus 1
          │
          └── PCA9685 (0x40)
                ├── CH0: Base servo (rotation)
                ├── CH1: Shoulder servo
                ├── CH2: Elbow servo
                ├── CH3: Wrist pitch servo
                ├── CH4: Wrist roll servo
                └── CH5: Gripper servo

Code:

python

from robo_infra.platforms import get_i2c
from robo_infra.drivers import PCA9685Driver
from robo_infra.actuators import Servo, ServoGroup
from robo_infra.core.types import Limits

# Initialize hardware
i2c = get_i2c(bus=1)
driver = PCA9685Driver(i2c_bus=i2c, frequency=50)

# Define servos with limits
servos = ServoGroup([
    Servo("base", driver, channel=0, limits=Limits(-90, 90)),
    Servo("shoulder", driver, channel=1, limits=Limits(0, 180)),
    Servo("elbow", driver, channel=2, limits=Limits(0, 135)),
    Servo("wrist_pitch", driver, channel=3, limits=Limits(-90, 90)),
    Servo("wrist_roll", driver, channel=4, limits=Limits(-180, 180)),
    Servo("gripper", driver, channel=5, limits=Limits(0, 45)),
])

# Home position
await servos.home()

# Move to target
await servos.move_to({
    "base": 45,
    "shoulder": 90,
    "elbow": 45,
    "gripper": 30,
})

3.2 Mobile Robot (Differential Drive)

Two-wheel differential drive robot:

code

Raspberry Pi 4
    │
    ├── GPIO (Direct)
    │     ├── GPIO18: Left motor PWM
    │     ├── GPIO23: Left motor IN1
    │     ├── GPIO24: Left motor IN2
    │     ├── GPIO19: Right motor PWM
    │     ├── GPIO25: Right motor IN1
    │     └── GPIO26: Right motor IN2
    │
    └── I2C Bus 1
          └── MPU6050 (0x68) - IMU for orientation

Code:

python

from robo_infra.platforms import get_gpio, get_i2c
from robo_infra.actuators import DCMotor
from robo_infra.sensors import MPU6050
from robo_infra.core.pin import PinMode

# Motor setup
left_motor = DCMotor(
    pwm_pin=get_gpio(18, mode=PinMode.PWM, frequency=1000),
    in1_pin=get_gpio(23),
    in2_pin=get_gpio(24),
)

right_motor = DCMotor(
    pwm_pin=get_gpio(19, mode=PinMode.PWM, frequency=1000),
    in1_pin=get_gpio(25),
    in2_pin=get_gpio(26),
)

# IMU for heading
imu = MPU6050(i2c=get_i2c(bus=1))

# Drive forward
left_motor.forward(speed=0.5)
right_motor.forward(speed=0.5)

# Turn right
left_motor.forward(speed=0.5)
right_motor.backward(speed=0.5)

3.3 Sensor Array

Multiple I2C sensors on same bus:

code

Raspberry Pi 4
    │
    └── I2C Bus 1
          ├── MPU6050 (0x68) - IMU
          ├── BMP280 (0x76)  - Barometer
          ├── HMC5883L (0x1E) - Magnetometer
          └── VL53L0X (0x29) - ToF distance sensor

Code:

python

from robo_infra.platforms import get_i2c

# Single I2C bus, multiple devices
i2c = get_i2c(bus=1)

# Scan for devices
devices = i2c.scan()
print(f"Found {len(devices)} I2C devices: {[hex(d) for d in devices]}")

# Read from each sensor
imu_data = i2c.read_block(0x68, 0x3B, 14)  # MPU6050 accel/gyro
baro_data = i2c.read_block(0x76, 0xF7, 6)  # BMP280 pressure/temp

Part 4: Troubleshooting

4.1 I2C Issues

No devices detected:

bash

# Check I2C is enabled
ls /dev/i2c*
# Should show: /dev/i2c-1

# Check wiring with oscilloscope or logic analyzer
# SDA and SCL should have ~3.3V pull-ups

# Try slower I2C speed
sudo nano /boot/config.txt
# Add: dtparam=i2c_baudrate=50000

Intermittent communication:

bash

# Add external pull-up resistors (4.7kΩ to 3.3V)
# Shorten wires (< 30cm recommended)
# Check power supply is adequate

4.2 Servo Issues

Servo jitter:

python

# Increase PWM frequency precision
driver = PCA9685Driver(i2c_bus=i2c, frequency=50)

# Add decoupling capacitors near servos
# Use separate power supply for servos

Servo not moving:

bash

# Check V+ has power (5-6V)
# Verify correct channel number
# Test with known-good servo

4.3 Power Issues

System unstable when motors run:

bash

# Use separate power supply for motors
# Add large capacitors (1000-4700µF) near motor driver
# Don't power motors from Raspberry Pi 5V

Voltage drops:

bash

# Check power supply capacity
# Each servo: ~200-500mA
# DC motors: ~500mA-2A
# Total capacity should be 2x expected draw

4.4 Permission Issues

bash

# Add user to required groups
sudo usermod -aG gpio,i2c,spi $USER

# Reboot or re-login
sudo reboot

# Verify groups
groups
# Should include: gpio i2c spi

Part 5: Quick Reference

Pin Reference (Raspberry Pi 4/5)

Function	GPIO (BCM)	Pin	Description
I2C SDA	2	3	I2C data
I2C SCL	3	5	I2C clock
SPI MOSI	10	19	SPI data out
SPI MISO	9	21	SPI data in
SPI SCLK	11	23	SPI clock
SPI CE0	8	24	SPI chip select 0
SPI CE1	7	26	SPI chip select 1
PWM0	12, 18	32, 12	Hardware PWM
PWM1	13, 19	33, 35	Hardware PWM
UART TX	14	8	Serial transmit
UART RX	15	10	Serial receive

Common I2C Addresses

Device	Address	Alternate
PCA9685	0x40	0x41-0x7F (configurable)
MPU6050	0x68	0x69 (AD0=VCC)
BMP280	0x76	0x77 (SDO=VCC)
HMC5883L	0x1E	-
VL53L0X	0x29	Programmable
OLED SSD1306	0x3C	0x3D

Voltage Levels

Component	Logic	Power
Raspberry Pi GPIO	3.3V	-
PCA9685	3.3-5V	5-6V (servos)
MPU6050	3.3V	3.3V
L298N	5V	6-12V (motors)
Servos	3.3-5V signal	5-6V
DC Motors	-	6-12V

Next Steps

Hardware Wiring Diagrams - Visual wiring guides
Hardware Testing - Validate your setup
Platform Support - Other platforms
Building a Robot Arm - Complete tutorial

Hardware Setup Guide

Overview

Part 1: Raspberry Pi Setup

1.1 Operating System

1.2 Enable Hardware Interfaces

1.3 Verify I2C

1.4 Install robo-infra

Part 2: Hardware Connections

2.1 PCA9685 PWM Driver

2.2 Servo Motors

2.3 MPU6050 IMU

2.4 DC Motors with L298N

Part 3: Common Hardware Setups

3.1 Robot Arm (6-DOF)

3.2 Mobile Robot (Differential Drive)

3.3 Sensor Array

Part 4: Troubleshooting

4.1 I2C Issues

4.2 Servo Issues

4.3 Power Issues

4.4 Permission Issues

Part 5: Quick Reference

Pin Reference (Raspberry Pi 4/5)

Common I2C Addresses

Voltage Levels

Next Steps

Hardware Setup Guide

Overview

Part 1: Raspberry Pi Setup

1.1 Operating System

1.2 Enable Hardware Interfaces

1.3 Verify I2C

1.4 Install robo-infra

Part 2: Hardware Connections

2.1 PCA9685 PWM Driver

2.2 Servo Motors

2.3 MPU6050 IMU

2.4 DC Motors with L298N

Part 3: Common Hardware Setups

3.1 Robot Arm (6-DOF)

3.2 Mobile Robot (Differential Drive)

3.3 Sensor Array

Part 4: Troubleshooting

4.1 I2C Issues

4.2 Servo Issues

4.3 Power Issues

4.4 Permission Issues

Part 5: Quick Reference

Pin Reference (Raspberry Pi 4/5)

Common I2C Addresses

Voltage Levels

Next Steps