Swift hardware hacking @ try! Swift

Swift Hardware Hacking
Sally Shepard

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First Local Cat Savings Bank!
Congratulations on joining
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Video of coin bank
Savings account v1.0
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Savings account v2.0
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Ready for deposit
£4.85

How to: Build the smart savings account
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Step 0: Setup development environment
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Install Swift on Raspberry Pi
curl -s https://packagecloud.io/install/
repositories/swift-arm/release/script.deb.sh |
sudo bash
sudo apt install swift4 //if on 3B+
sudo apt install swift4rpi01 //if using a Zero
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Create a project
mkdir ~/Documents/<project-name>
cd ~/Documents/<project-name>
swift package init --type executable

Setting up Geany for build/run
Reference: https://www.geany.org/manual/current/index.html
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Step 1: Controlling power to the bank
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Dependencies ->
dependencies: [
// Dependencies declare other packages that this package depends on.
.package(url: "https://github.com/uraimo/SwiftyGPIO.git", from: "1.0.0")]
.target( name: "GeePeeEyeOh",
dependencies: ["SwiftyGPIO"])
Reference: https://github.com/uraimo/SwiftyGPIO
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Relay.swift
import SwiftyGPIO
struct Relay {
var state: State {
get {
if let pin = self.gpio {
switch pin.value {
case 1:
return .On
default:
return .Off
}
}
return .Off
}
}
private var gpio: RaspberryGPIO?
init() {
setup()
}
init(connectTo pin: RaspberryGPIO) {
self.gpio = pin
setup()
}
private mutating func setup() {
if self.gpio == nil {
let gpios = SwiftyGPIO.GPIOs(for: .RaspberryPiPlusZero)
self.gpio = gpios[.P4] as? RaspberryGPIO
}
if let gpio = self.gpio {
gpio.direction = .OUT
}
}
public func switchTo(_ state: State) {
if let gpio = self.gpio {
gpio.value = state.rawValue
}
}
}
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Digital Signal
0
1
1 = 3.3v 1 = 3.3v
0 = 0v 0 = 0v
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Step 2: tell when the lid is open
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Analogue Signal
0
128
256
384
512
640
768
896
1024
768
140
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Dependencies -> MCP3008.swift
dependencies: [
.package(url: "https://github.com/uraimo/SwiftyGPIO.git", from: “1.0.0”),
.package(url: "https://github.com/uraimo/MCP3008.swift.git", from: “2.0.0")]
dependencies: [“SwiftyGPIO”, “MCP3008”])
Reference: https://github.com/uraimo/MCP3008
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import SwiftyGPIO
struct Photoresistor {
private var maxLightThreshold: UInt32 = 0
private var minLightThreshhold: UInt32 = 1024
private var tolerance: UInt32 = 10
var lightReading: UInt32 = 1024
var light: Bool {
get {
let lightRange = 0...(lightReading + tolerance)
return lightRange.contains(lightReading)
}
}
init(light minLightThreshhold: UInt32,
dark maxLightThreshold: UInt32,
tolerance tolerance: UInt32) {
self.minLightThreshhold = minLightThreshhold
self.maxLightThreshold = maxLightThreshold
self.tolerance = tolerance
self.init()
}
}
Photoresistor.
swift
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Step 3: ﬁguring out what coin was deposited
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coin weight = currentDeposit - previousDeposit
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Red E+
Black E-
White A-
Green A+
Ground
DF
SCK
Vcc

Analogue to Digital?
140
768
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140
768
0000 1000 1100
0011 0000 0000
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0000 1000 1100
0011 0000 0000
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0 0 0 0 0 0 1 0 1 0 0 1
word length = 12 bits
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import SwiftGPIO
struct HX711 {
var dt: RaspberryGPIO?
var sck: RaspberryGPIO?
init() {
let gpios = SwiftyGPIO.GPIOs(for:.RaspberryPiPlusZero)
dt = gpios[.P5] as? RaspberryGPIO
sck = gpios[.P6] as? RaspberryGPIO
self.setup()
}
init(data dt: RaspberryGPIO, clock ck: RaspberryGPIO) {
self.dt = dt
self.sck = ck
self.setup()
}
private func setup() {
if let dt = self.dt, let sck = self.sck {
dt.direction = .IN
sck.direction = .OUT
}
}
// read from the Data pin
public func readData() -> Int {
if let dt = self.dt {
if dt.value == 0 {
for _ in 0..<24 {
self. sck.value = 1
if let dt = self.dt {
//MAKE BITS DO THINGS HERE
}
self. sck.value = 0
}
} else {
print("Not Ready")
}
}
}
}
HX711.swift
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Step 5: Bluetooth connection to iOS
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Bluetooth Low Energy
“Central”
client
“Peripheral”
server
GATT Profile
0x180A
“Device Information”
• Manufacturer Name
• Model Number
• Serial Number
• Hardware/Firmware/Software
Revision
• System ID
• Certification List
• Device ID
GATT Profile
0x180F
“Battery Service”
• Battery Level
• Level Changed
Notify
“Battery Level
Changed”
• Battery Percentage
(optional)
Write
“User Data - First Name”
Read
“Device Information -
Serial Number”
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Core
Bluetooth
API
PureSwift/Bluetooth
PureSwift/BluetoothLinux
PureSwift/GATT
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dependencies: [
.package(url: "https://github.com/uraimo/SwiftyGPIO.git", from: “1.0.0”),
.package(url: "https://github.com/uraimo/MCP3008.swift.git", from: “2.0.0”),
.package(url: "https://github.com/PureSwift/BluetoothLinux.git", from: “3.0.0"),
.package(url: "https://github.com/PureSwift/GATT.git", from : "1.0.0")]
dependencies: [“SwiftyGPIO”, “MCP3008”, “BluetoothLinux”, “GATT”])
Reference: https://github.com/PureSwift/BluetoothLinux https://github.com/PureSwift/GATT
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Core Bluetooth
// Core Bluetooth Manager
var centralManager = CBCentralManager(delegate: self, queue: DispatchQueue.main)
centralManager?.scanForPeripherals(withServices: nil, options: nil)
// Delegate Methods for Bluetooth Central Manager
func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData:
[String : Any], rssi RSSI: NSNumber)
// Delegate methods for connected peripherals
func peripheral(_ peripheral: CBPeripheral, didDiscoverServices error: Error?)
func peripheral(_ peripheral: CBPeripheral, didDiscoverCharacteristicsFor service: CBService, error: Error?)
func peripheral(_ peripheral: CBPeripheral, didUpdateValueFor characteristic: CBCharacteristic, error: Error?)
// Peripheral methods
peripheral.writeValue(data, for: descriptor)
peripheral.readValue(for: descriptor)
peripheral.setNotifyValue(true, for: characteristic)
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Bluetooth Linux
// Instantiate controller & peripheral
let controller = HostController.default
let peripheral = PeripheralManager(controller: controller)
// configure service(s)
let service = BluetoothUUID(rawValue: “180A”), // Hex value of GATT Service
let controllerType = serviceControllers.first(where: { $0.service == service })
let serviceController = try controllerType.init(peripheral: peripheral)
// start the peripheral
try peripheral.start()
Reference: https://github.com/MillerTechnologyPeru/gattserver
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Thank you for listening!
Sally Shepard

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Swift hardware hacking @ try! Swift

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