Published © MIT

Swift 3.0 for Raspberry Pi! GPIO - Getting Started

In this tutorial we will learn how to use the Swift GPIO module to control the GPIO pins by flashing an LED.

EasyProtip1 hour4,055
Swift 3.0 for Raspberry Pi! GPIO - Getting Started

Things used in this project

Hardware components

Raspberry Pi 3 Model B
Raspberry Pi 3 Model B
LED (generic)
LED (generic)
Breadboard (generic)
Breadboard (generic)
Resistor 330 ohm
Resistor 330 ohm
Jumper wires (generic)
Jumper wires (generic)

Software apps and online services

Raspberry Pi Raspbian Jessie


Read more


GPIO Pin Layout

GPIO pin layout diagram for the Raspberry Pi 40 pin models



Swift 3.0 project file for Flash LED tutorial
// Created with PiCode for Swift 3.0
// A Swift-Lite project file
// type:project
// name:piCodeLEDTimer
// include:piCodeGPIO.swift

import Foundation

// auto detect board type (detects all boards with 40 GPIO pins)
let gpios = autoDetectBoardType()

// for older boards with 26 GPIO pins please set board type manually
//let gpios = PiCodeGPIO.RPIRev1
//let gpios = PiCodeGPIO.RPIRev2

// setup the GPIO pins
var gp = gpios[.P17]!   // Pin to conect the LED to
gp.direction = .OUT     // Pin connection direction - OUT - when turned on the pin will output 5v
gp.value = 0            // Set intial value 0 = off 1 = on

var intervalTimer: Timer!   // this timer controls the time intervals the LED turns on. As this is a repeating timer it needs to be added to a runloop.
var flashTimer: Timer!      // this timer controls the length of time the LED remains on.

var flashNumber = 5 // the number of flashes

var flashIntervalTime: Double = 2.0 // the time between the start of each flash

var flashLengthTime: Double = 0.75 // the length of time of each flash 

var runLoopTime: Double = 11 // the lenghth of time the runloop will run - set this to be longer than the time for all the flashes to complete
                             // the runloop can be set to continous if the is action you need.

func runIntervalTimer() {
    intervalTimer = Timer.scheduledTimer(withTimeInterval: flashIntervalTime, repeats: true, block: {(_) in flashOnLED()})

func runflashTimer() {
    flashTimer = Timer.scheduledTimer(withTimeInterval: flashLengthTime, repeats: false, block: {(_) in flashOffLED()})

func flashOnLED() {
    print("flash on")
    gp.value = 1

func flashOffLED() {
    gp.value = 0
    print("flash off")
    flashNumber -= 1
    if flashNumber == 0 {


let flashLEDLoop = RunLoop.current
flashLEDLoop.add(intervalTimer, forMode: .defaultRunLoopMode)

flashLEDLoop.run(until: Date(timeIntervalSinceNow: runLoopTime))




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Development Engineer at Swift-Arm - Bringing Swift to the Raspberry Pi and other Arm SBC's. Designer and creator of Swift-Lite.