Swift package `SenseHat` for Raspberry Pi Sense Hat

Features:

✅ blink with LED - that what everyone starts from playing with Raspberry Pi;
✅ get/set color to individual pixels;
✅ set color to all pixels in one shot;
✅ get/set all pixels in one shot (to/from Data);
✅ show 8x8 characters on LCD matrix (supported ascii, extended latin, box drawings elements, block elements, Hiragana, Greek, sga);
✅ show arbitrary text (8x8 font, horizontal scroll);
✅ rotating of LED matrix 0º/90º/180º/270º;
✅ set orientation of LED matrix 0º/90º/180º/270º and make all get/set primitives respect it;
✅ read joystick;
✅ read humidity and pressure sensors;
✅ read gyroscope/accelerometer/magnitometer sensors;
✅ snake game;
✅ life game;

TODO:

improve gyroscope/accelerometer/magnetometer sensors reading;
add conversion of RGB color to Rgb565;
add Cyrillic font 8x8;
add 3x5 font;
replace C fonts with Swift ones;
show arbitrary image on LED matrix;
show preprocessed video;
menu to show readings from any of available sensors;
mode for rotating screen depending on gyro readings;
emulator of SenseHat LED matrix for Web;
Kalman filtering for accelerometer/gyro/magnetometer;
add analog clock demo app.

Usage

Instantiating

// Look over all frame buffer devices in `/dev/` for one of Sense Hat. 
// Use default orientation `.up`
guard let senseHat = SenseHat() else {
    fatalError("Can't initialise Raspberry Pi Sense Hat")
}

Parameter orientation could be used for other orientations” SenseHat(orientation: .left). Parameter frameBufferDevice could be use for specific frame buffer device: SenseHat(frameBufferDevice: "/dev/fb0"). Both parameters could be used: SenseHat(frameBufferDevice: "/dev/fb0", orientation: .down).

Parameter orientation defines where top of the LED matrix will be. Here are example of the same character "1" shown with different orientations:

`.up`	`.left`	`.right`	`.down`

Set all LEDs of matrix to specific color

senseHat.set(color: .red) // sets all LEDs of matrix to red

Red

senseHat.set(color: .black) // sets all LEDs of matrix to black, literally turns them off

Black

Set specific LED of matrix to specific color

senseHat.set(color: .black) // clear
senseHat.set(x: 0, y: 0, color: .white) // set most top left LED to white using function syntax
senseHat[7, 7] = .green // set most bottom right LED to green using subscript syntax

White and green

Coordinates x and y should belong to 0..<7 range.

Show character on LED matrix

senseHat.show(character: Character("A"), color: .blue)

senseHat.show(character: Character("π"), color: .yellow, background: .blue)

Show string on LED matrix

senseHat.show(string: "Hello! ", secPerChar: 0.5, color: .yellow, background: .blue)

Hello!

senseHat.orientation = .left
senseHat.show(string: "Απόλλων ", secPerChar: 0.5, color: .red, background: .darkGray)

Greek

senseHat.orientation = .right
senseHat.show(string: "ここからそこまで ", secPerChar: 0.5, color: .white, background: .brown)

Hiragana

senseHat.orientation = .down
senseHat.show(string: "Fußgängerübergänge ", secPerChar: 0.5, color: .white, background: .purple)

deutsch

Reading humidity sensor

if let h = senseHat.humidity() {
    let strH = String(format: "%.1lf", h.H_rH)
    senseHat.show(string: "Humidity \(strH)% rH ", secPerChar: 0.5, color: .yellow, background: .black)
    let strT = String(format: "%.1lf", h.T_DegC)
    senseHat.show(string: "Temperature \(strT)ºC", secPerChar: 0.5, color: .yellow, background: .black)
} else {
    print("Cannot read humidity sensor")
}

humidity

Reading pressure sensor

if let p = senseHat.pressure() {
    let strP = String(format: "%.1lf", p.P_hPa)
    let strT = String(format: "%.1lf", p.T_DegC)
    senseHat.show(string: "Pressure \(strP) hPa ", secPerChar: 0.5, color: .yellow, background: .black)
    senseHat.show(string: "Temperature \(strT)ºC", secPerChar: 0.5, color: .yellow, background: .black)
} else {
    print("Cannot read pressure sensor")
}

pressure

Useful links

Unfortunately Data sheet or Programmer’s manual for Raspberry Pi Sense Hat doesn’t exist or I have failed to find it. Here are some useful links:

Official page on raspberrypi.org Sense HAT;
Astro Pi: Flight Hardware Tech Specs names all sensors of SenseHat with links on datasheets;
Official documentation Documentation for Sense HAT;
Official Python module sense-hat;
Source of Python module sense-hat;
Getting started with the Sense HAT;
Rust library sensehat-screen where it’s explained how RGB is packed in two bytes in so called Rgb565;
Linux The Frame Buffer Device API used to access pixel buffer;
Data sheet for LSM9DS1, this might be useful Reading from FIFO;
Guide to install Swift on Raspberry Pi buildSwiftOnARM used to install prebuilt Swift 5.1.5 TODO: describe what I’ve done differently;
3D printing Astro Pi case.

Blinking

Swift package SenseHat for Raspberry Pi Sense Hat