Datasheet

function return true if characteristics is found, and false otherwise. You could also check with .discovered() function. A

service could contain more characteristics but we don't need to discover them all, only those that we want to interact

with.

Advanced: Alternatively, you could discover all the interested characteristics of a service within a function call by

using Bluefruit.Discovery.discoverCharacteristic() (not used in the example). The API can take up to 5 characteristics, if you

need more, the variant with passing array of characteristics is also available. The function will return the number of

characteristic it found.

Note: when a characteristic is discovered by above API, all necessarily meta data such as handles, properties (

read,write, notify etc ...), cccd handle will be updated automatically. You can then

use BLECLientCharacteristic (https://adafru.it/Cng) API such as read(), write(), enableNotify() on it provided that its

properties support such as operation.

5. Once hrmc is discovered, you should enable its notification by calling hrmc.enableNotify() . If this succeeded (return

true), peripheral can now send data to us using notify message. Which will trigger the callback that we setup earlier to

handle incoming data.

// Connect Callback Part 2

void connect_callback(uint16_t conn_handle)

{

Serial.print("Discovering Measurement characteristic ... ");

if ( !hrmc.discover() )

{

// Measurement chr is mandatory, if it is not found (valid), then disconnect

Serial.println("not found !!!");

Serial.println("Measurement characteristic is mandatory but not found");

Bluefruit.Central.disconnect(conn_handle);

return;

}

Serial.println("Found it");

// Measurement is found, continue to look for option Body Sensor Location

// https://www.bluetooth.com/specifications/gatt/viewer?attributeXmlFile=org.bluetooth.characteristic.body_sensor_location.xml

// Body Sensor Location is optional, print out the location in text if present

Serial.print("Discovering Body Sensor Location characteristic ... ");

if ( bslc.discover() )

{

Serial.println("Found it");

// Body sensor location value is 8 bit

const char* body_str[] = { "Other", "Chest", "Wrist", "Finger", "Hand", "Ear Lobe", "Foot" };

// Read 8-bit BSLC value from peripheral

uint8_t loc_value = bslc.read8();

Serial.print("Body Location Sensor: ");

Serial.println(body_str[loc_value]);

}else

{

Serial.println("Found NONE");

}

...............

}