Discussion of Apple's HomeKit technologies

1. HomeKit
Inside And Out

2. Rolf Rando

3. HomeKit (Apple)
Weave / Brillo (Google / Nest)
SmartThings (Samsung)
Wink
WeMo (Belkin)

4. Launched in iOS8 (2014)
Little device support until iOS9
Home App, video & doorbell support
in iOS10

5. HomeKit Protocol
3rd Party
Apps
HomeKit API
Home App Siri
iCloud

7. Ways To Interact With HomeKit
3rd Party Apps through the HomeKit API
iPhone, iPad, WatchOS and AppleTV

8. Bluetooth Low Energy
Bluetooth Smart
Bluetooth LE
BLE

9. Frequency Modulation (FM)

10. Generic Attributes
GATT
Common operations framework
for data transport

13. Thermometer service
Lock Service
Temperature
Characteristic
Lock State
Characteristic
Angle
Characteristic

14. Bluetooth Advertising
•An accessory (‘peripheral’)
‘advertises’ by broadcasting basic
device info regular intervals. It can
also provide available services.
•Master devices (‘centrals’) must see
advertising data to discover devices
nearby as well as to connect to a
known device.

15. Communication Protocol
•40 specific frequency channels
around 2.4 GHZ.
•Host device (‘central’) learns of
interference and marks bad channels
as busy.
• 4 channels are reserved for the
advertising and initiating the
connection. Remainder are used for
data communication.

16. HomeKit Accessory Protocol
(HAP)
BLE
Proprietary Apple-defined
services and characteristics
Encryption / Pairing mechanism
iCloud

17. HomeKit Protocol
3rd Party
Apps
HomeKit API
Home App Siri

18. Pairing
HomeKit accessories generate their own Ed25519 key pair
for use in communicating with iOS devices. If the accessory
is restored to factory settings, a new key pair is generated.
Ed25519 = Edwards-curve Digital Signature Algorithm
(EdDSA)
https://www.apple.com/business/docs/iOS_Security_Guide.pdf

19. - Add HomeKit Framework
- Enable Capabilities
Getting Started With HomeKit

21. HMHomeManager
..
self.homeManager = [[HMHomeManager alloc] init];
self.homeManager.delegate = self;
…
-(void) didUpdateHomes:(HMHomeManager *) manager {
[self.tableView reloadData]
}

22. HMHome
HMRoom
HMZone

23. HMAccessory

24. HMService
HMCharacteristic

25. HMServiceTypeLockMechanism
HMCharacteristicTypeCurrentLockMechanismState

26. HMHome isPrimaryHome

27. NSArray *lightServices = [self.homeKitManager.primaryHome
servicesWithTypes:@[HMServiceTypeLightbulb]];

28. #define kHomeKitStateUnlocked
HMCharacteristicValueLockMechanismStateUnsecured
#define kHomeKitStateLocked
HMCharacteristicValueLockMechanismStateSecured
HMAccessory *homeKitLock;
. . .
// Lock a door
if (homeKitLock.isReachable == false) {
return;
}
for (HMService *service in homeKitLock.services) {
if ([service.serviceType isEqualToString: HMServiceTypeLockMechanism]) {
for (HMCharacteristic *characteristic in service.characteristics){
if ([characteristic.characteristicType isEqualToString:
HMCharacteristicTypeTargetLockMechanismState]) {
[characteristic writeValue:[NSNumber
numberWithInt:kHomeKitStateUnlocked] completionHandler:^(NSError * _Nullable
error) {
if (error==nil) {
NSLog(@“Door was locked”);
}
}];
. . .

29. HMAction
HMActionSet

30. HMScene

31. HMTrigger
HMTimerTrigger *newTrigger = [[HMTimerTrigger alloc] initWithName:@"Wake Up Time"
fireDate:self.wakeUpTime
timeZone:nil
recurrence:nil
recurrenceCalendar:nil];

32. [primaryHome addActionSetWithName:@"Wake Action" completionHandler:^(HMActionSet *actionSet,
NSError *error) {
if (error == nil) {
HMCharacteristicWriteAction *writeAction = [[HMCharacteristicWriteAction alloc]
initWithCharacteristic:lightCharacteristic targetValue:[NSNumber numberWithFloat:30.0]];
[actionSet addAction:writeAction completionHandler:^(NSError * _Nullable error) {
}];
}
}];

33. [newTrigger addActionSet:actionSet completionHandler:^(NSError * _Nullable error) {
if (error !=nil) {
[primaryHome addTrigger:newTrigger completionHandler:^(NSError * _Nullable error)
{
if (error != nil) {
[newTrigger enable:true completionHandler:^(NSError * _Nullable error) {
. . .
}];
}
}];
}
}];

34. HMEvent
HMCharacteristicEvent
HMLocationEvent

35. Triggers a HMScene when a combination of characteristic and location events
occur.
+ (NSPredicate
*)predicateForEvaluatingTriggerOccurringAfterSignificantEvent
:(NSString *)significantEvent
applyingOffset:(NSDateComponents *)offset;
+ (NSPredicate
*)predicateForEvaluatingTriggerOccurringBeforeSignificantEven
t:(NSString *)significantEvent
applyingOffset:(NSDateComponents *)offset;
HMEventTrigger

36. Development Tips
Allocating
HMHomeManager initiates permission request to user
Surface HomeKit error messages to user.
error.localizedDescription
HMCatalogApp Source Code
Service name = Siri name
Often HomeKit header files have more details than
documentation.

37. Application Ideas
-Augment existing app
-Automation designer

38. Making a HomeKit
Accessory

39. Making a HomeKit
Accessory
• Apply to Apple’s Mfi program
• Most major hardware vendors have chips solutions
that come with a HomeKit SDK, and encryption
built in.
• Accessory must be certified by Apple to ship
• Some devices are not exclusively for HomeKit
platform.

40. Personal electronics
projects
• Piggy-back off of an existing HomeKit device.
• HomeControl HomeKit implementation in (GO)
• Open HABHomeKit bridge (node.js)

41. Questions?

42. Thanks!
Rolf Rando
@rolfro
rolf (at) august.com