GPIO & Hardware Nodes

Hardware interface nodes provide direct access to GPIO pins, I2C, SPI, 1-Wire, and serial communication. Perfect for building IoT devices and embedded systems with Raspberry Pi.

28 Nodes

5 Protocols

40 GPIO Pins

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gpio-in gpio-out pwm i2c spi 1-wire serial interrupt

gpio-in

Read digital input from GPIO pins. Supports pull-up/pull-down resistors and edge detection.

Input Digital HIGH/LOW

Pull Up, down, or none

Edge Rising, falling, both

Debounce Configurable (50ms)

Configuration

{cfg.key} number GPIO pin number (BCM)

{cfg.key} string "up" | "down" | "none"

{cfg.key} string "rising" | "falling" | "both"

{cfg.key} number Milliseconds to debounce

Output Example

{node.details.output}

Use BCM pin numbering, not physical pin numbers. GPIO17 is physical pin 11.

gpio-out

Control digital output on GPIO pins. Set pins high or low, or toggle state.

Output HIGH, LOW, toggle

Initial Configurable state

Current 16mA per pin max

Voltage 3.3V logic level

Configuration

{cfg.key} number GPIO pin number (BCM)

{cfg.key} string "high" | "low"

{cfg.key} string "set" | "toggle"

Output Example

{node.details.output}

For loads > 16mA, use a transistor or relay. Never connect motors directly.

pwm

Popular

Generate PWM signals for LED dimming, motor speed control, and servo positioning.

Hardware GPIO12, 13, 18, 19

Frequency 1Hz - 1MHz

Duty Cycle 0-100% (0.1% res)

Servo 500-2500μs pulse

Configuration

{cfg.key} number GPIO pin number

{cfg.key} number PWM frequency in Hz

{cfg.key} number 0-100 percentage

{cfg.key} string "pwm" | "servo"

Output Example

{node.details.output}

Hardware PWM (GPIO12, 13, 18, 19) is more precise. Use software PWM for other pins.

i2c

Popular

Communicate with I2C devices like sensors, displays, and expanders.

Bus GPIO2=SDA, GPIO3=SCL

Speed 100kHz or 400kHz

Address 7-bit (0x03-0x77)

Devices Up to 127 per bus

Configuration

{cfg.key} string Device I2C address (hex)

{cfg.key} number I2C bus number (default: 1)

{cfg.key} string Register address to read/write

{cfg.key} number Bytes to read

Output Example

{node.details.output}

Enable I2C with sudo raspi-config. Use i2cdetect -y 1 to scan for devices.

spi

High-speed SPI communication for displays, ADCs, and flash memory.

Pins MOSI/MISO/SCLK

Chip Select GPIO8, GPIO7

Speed Up to 125MHz

Modes 0, 1, 2, 3

Configuration

{cfg.key} number 0 (CE0) or 1 (CE1)

{cfg.key} number Clock speed in Hz

{cfg.key} number SPI mode (0-3)

{cfg.key} number Usually 8

Output Example

{node.details.output}

SPI is full-duplex: data sent and received simultaneously. Enable via raspi-config.

1-wire

Read data from 1-Wire devices like DS18B20 temperature sensors.

Default Pin GPIO4

Protocol Dallas 1-Wire

Devices DS18B20, DS1822

Multi-device 10+ per bus

Configuration

{cfg.key} number GPIO pin (default: 4)

{cfg.key} string Specific ID or "all"

{cfg.key} number 9, 10, 11, or 12 bits

{cfg.key} number Polling interval in ms

Output Example

{node.details.output}

Requires 4.7kΩ pull-up resistor. Enable overlay: dtoverlay=w1-gpio.

serial

Serial port communication (UART) for GPS modules, displays, and other devices.

Pins GPIO14 TX, GPIO15 RX

Baud 300 - 4000000

Data Bits 5, 6, 7, 8

Parity None, Even, Odd

Configuration

{cfg.key} string /dev/ttyS0 or /dev/ttyAMA0

{cfg.key} number 9600, 115200, etc.

{cfg.key} number 8

{cfg.key} string "none" | "even" | "odd"

Output Example

{node.details.output}

Disable serial console first via raspi-config. TX/RX are 3.3V logic.

interrupt

Hardware interrupt handling for time-critical event detection.

Trigger Rising, falling, both

Latency < 100μs typical

Priority Hardware-level

Timestamp Microsecond precision

Configuration

{cfg.key} number GPIO pin number

{cfg.key} string "rising" | "falling" | "both"

{cfg.key} number Debounce time in μs

{cfg.key} number Max wait time (0 = forever)

Output Example

{node.details.output}

More efficient than polling. Use for buttons, encoders, and event sensors.

GPIO Pin Reference

Power Pins

3.3V and 5V power outputs. Never connect 5V to GPIO - it will damage your board.

Digital GPIO

General purpose I/O pins for digital signals. Use BCM numbering (GPIO17, not pin 11).

I2C Bus

GPIO2 (SDA) and GPIO3 (SCL) for I2C devices. Supports 100kHz and 400kHz speeds.

SPI Bus

GPIO10 (MOSI), GPIO9 (MISO), GPIO11 (SCLK). Two chip selects: CE0 and CE1.

More GPIO & Hardware Nodes

relay

Relay module control

servo

Servo motor positioning

motor-l298n

DC motor driver

buzzer

Piezo buzzer control

ws2812

Addressable LED strips

rtc-ds3231

Real-time clock (high precision)

rtc-ds1307

Real-time clock

rtc-pcf8523

Real-time clock (low power)

lcd-i2c

Character LCD display

oled-ssd1306

OLED graphic display

lora-sx1276

LoRa transceiver

nrf24l01

2.4GHz radio transceiver

rfid-rc522

RFID card reader

nfc-pn532

NFC reader/writer

can-mcp2515

CAN bus interface

rf433

433MHz RF transceiver

modbus-gpio

Modbus GPIO bridge

pi-camera

Raspberry Pi camera

audio

Audio playback/recording

Continue Learning

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