2015 Pebble Developer Retreat

Smartstraps

Brian Gomberg

What is a smartstrap?

Electrical Connection

GND GNDDATA PWR

Smartstrap Protocol

Smartstrap Protocol

•Master / slave model (watch is master)

•Notification mechanism

•Data arrives intact or not at all

Physical Layer

Link Layer

Profile Layer

Link Control Profile Raw Data Profile Generic Service Profile

Generic Service Profile

•Attributes and Services:

•An attribute is a distinct piece of information

•A service is a collection of related attributes

Defining Services and Attributes

Connection Process

Charging flux capacitors!

What profiles do you support?

I support ALL the profiles!

Profile Discovery

All Profiles Supported

Woot! Are you ready to go?

Let’s talk faster.Status Request

Change Baud Rate

What services do you support?

I support service 0x1234, the best service.

Service Discovery

Service 0x1234

static SmartstrapAttribute *color_attr;

static void init(void) { const SmartstrapServiceId service_id = 0x1234; const SmartstrapAttributeId attribute_id = 0x0042; const size_t length = 1; color_attr = smartstrap_attribute_create(service_id, attribute_id, length); smartstrap_subscribe((SmartstrapHandlers) { ... });}

static void deinit(void) { smartstrap_attribute_destroy(color_attr); smartstrap_unsubscribe();}

static const uint16_t SERVICES[] = {0x1234};static uint8_t buffer[GET_PAYLOAD_BUFFER_SIZE(1)];

void setup() { const uint8_t pin = 1; ArduinoPebbleSerial::begin_software(pin, buffer, sizeof(buffer), Baud57600, SERVICES, 1);}

Reading Attributes

What is your favorite color?

I like green.

Read 0x1234, 0x0042

0b11001100

smartstrap_attribute_read(color_attr);

uint16_t service_id, attribute_id;size_t length;RequestType type;if (ArduinoPebbleSerial::feed(&service_id, &attribute_id, &length, &type)) { // ... buffer[0] = 0b11110111; ArduinoPebbleSerial::write(true, buffer, 1);}

static void prv_did_read_handler(SmartstrapAttribute *attribute, SmartstrapResult result, const uint8_t *data, size_t length) { // handle read...}

Notifications

Wait! I change my mind!

Notification

0x1234, 0x0042

ArduinoPebbleSerial::notify(0x1234, 0x0042);

static void prv_notify_handler(SmartstrapAttribute *attribute) { // ...}

Demo

Smartstrap AdapterPebble Time Teensy 3.1

Links• Documentation: http://developer.pebble.com/guides/hardware/

• Arduino Library: https://github.com/pebble/ArduinoPebbleSerial

• Teensy 3.2: https://www.pjrc.com/store/teensy32.html

Examples

Questions?

Slack Room: #smartstraps Email: bgomberg@pebble.com