Bluetooth Low Energy / Mbed 2 deprecated BLE_GAP_Example

This example program shows how to set up a GAP advertising packet to broadcast data from the device out to anyone who may be listening.

Dependencies:   BLE_API mbed nRF51822

Fork of BLE_EvothingsExample_GAP by Austin Blackstone

Intro

This code is meant to demonstrate how to use the GAP advertising layer to transmit data. Keep in mind you only have 26B of data in the Manufacturer data field to use.

Video of use

Details

Fill in the data you want to transmit by changing the following line, try using the string representation by changing hte "CHangeThisData" field or send hex data by altering the hex data field. 

// You have up to 26 bytes of advertising data to use.
const static uint8_t AdvData[] = {"ChangeThisData"};             // example of character data
//const static uint8_t AdvData[] = {0x01,0x02,0x03,0x04,0x05};   // example of hex data

Name Device

Optionally you can give your device a name by uncommenting the following two lines

//const static char     DEVICE_NAME[]        = "ChangeMe!!"; // change this
...
//ble.accumulateAdvertisingPayload(GapAdvertisingData::COMPLETE_LOCAL_NAME, (uint8_t *)DEVICE_NAME, sizeof(DEVICE_NAME));

Add Disconnection Callback

This code is bare bones and as such does not restart advertising when disconnected from a device. To add this functionality into your code please add the following callback

// Restart advertising when phone app disconnects
void disconnectionCallback(Gap::Handle_t handle, Gap::DisconnectionReason_t reason)
{
    ble.startAdvertising(); 
}

and the following initialization to your main function

int 
main(void)
{
...
ble.onDisconnection(disconnectionCallback);
...

Viewing Data

You can use either the LightBlue app on iOS or the nRF Master Control Panel application on Android to view the advertising data. Alternatively you can use a custom Evothings App to view the data.

Evothings?

Evothings is a rapid prototyping environment that uses cordova to enable you to rapidly develop smartphone applications in Javascript. Please download the Evothings workbench to your computer and the Evothings client to your smartphone. In the Evothings Workbench you will find an example program called "mbed Evothings GAP", this Evothings Smartphone App is meant to be used with the above embedded mbed code. For instructions on how to use Evothings please see the reference section below.

Reference

main.cpp@8:5442739198ec, 2015-03-17 (annotated)

Committer:
mbedAustin
Date:
Tue Mar 17 19:45:19 2015 +0000
Revision:
8:5442739198ec
Parent:
7:f9a2fa5b1d43
Child:
11:c9c0c4586c5f
Added comments and disconnection callback option

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbedAustin 1:0692bee84264 1
mbedAustin 1:0692bee84264 2 // Headers necessary for mbed and BLE device mode
mbedAustin 0:5375be4301ed 3 #include "mbed.h"
mbedAustin 0:5375be4301ed 4 #include "BLEDevice.h"
mbedAustin 0:5375be4301ed 5
mbedAustin 1:0692bee84264 6 // BLE object
mbedAustin 1:0692bee84264 7 BLEDevice ble;
mbedAustin 0:5375be4301ed 8
mbedAustin 8:5442739198ec 9 // Optional name, add for human read-ability
mbedAustin 8:5442739198ec 10 //const static char DEVICE_NAME[] = "ChangeMe!!"; // Optional: device name
mbedAustin 5:fff16d283dcf 11
mbedAustin 1:0692bee84264 12 /**
mbedAustin 8:5442739198ec 13 * You have up to 26 bytes of advertising data to use.
mbedAustin 8:5442739198ec 14 * Make up your own encoding for these 26bytes, send it across
mbedAustin 8:5442739198ec 15 * and decode it using the evothings app.
mbedAustin 1:0692bee84264 16 */
mbedAustin 8:5442739198ec 17 //const static uint8_t AdvData[] = {"ChangeThisData"}; // example of character data
mbedAustin 7:f9a2fa5b1d43 18 const static uint8_t AdvData[] = {0x01,0x02,0x03,0x04,0x05}; // example of hex data
mbedAustin 1:0692bee84264 19
mbedAustin 8:5442739198ec 20 // Restart advertising when phone app disconnects
mbedAustin 8:5442739198ec 21 void disconnectionCallback(Gap::Handle_t handle, Gap::DisconnectionReason_t reason){
mbedAustin 8:5442739198ec 22 ble.startAdvertising();
mbedAustin 8:5442739198ec 23 }
mbedAustin 8:5442739198ec 24
mbedAustin 1:0692bee84264 25 // main program
mbedAustin 1:0692bee84264 26 int main(void)
mbedAustin 0:5375be4301ed 27 {
mbedAustin 1:0692bee84264 28 // Initialize BLE baselayer, always do this first!
mbedAustin 1:0692bee84264 29 ble.init();
mbedAustin 8:5442739198ec 30 // ble.onDisconnection(disconnectionCallback); // Optional: add callback for disconnection
mbedAustin 1:0692bee84264 31
mbedAustin 1:0692bee84264 32 // Sacrifice 3B of 31B to Advertising Flags
mbedAustin 1:0692bee84264 33 ble.accumulateAdvertisingPayload(GapAdvertisingData::BREDR_NOT_SUPPORTED | GapAdvertisingData::LE_GENERAL_DISCOVERABLE );
mbedAustin 4:d602b1c3aef4 34 ble.setAdvertisingType(GapAdvertisingParams::ADV_CONNECTABLE_UNDIRECTED);
mbedAustin 1:0692bee84264 35
mbedAustin 1:0692bee84264 36 // Sacrifice 2B of 31B to AdvType overhead, rest goes to AdvData array you define
mbedAustin 1:0692bee84264 37 ble.accumulateAdvertisingPayload(GapAdvertisingData::MANUFACTURER_SPECIFIC_DATA, AdvData, sizeof(AdvData));
mbedAustin 5:fff16d283dcf 38
mbedAustin 8:5442739198ec 39 // Optional: Add name to device
mbedAustin 5:fff16d283dcf 40 //ble.accumulateAdvertisingPayload(GapAdvertisingData::COMPLETE_LOCAL_NAME, (uint8_t *)DEVICE_NAME, sizeof(DEVICE_NAME));
mbedAustin 1:0692bee84264 41
mbedAustin 1:0692bee84264 42 // Set advertising interval. Longer interval = longer battery life
mbedAustin 1:0692bee84264 43 ble.setAdvertisingInterval(160); // 100ms; in multiples of 0.625ms.
mbedAustin 1:0692bee84264 44 ble.startAdvertising();
mbedAustin 1:0692bee84264 45
mbedAustin 1:0692bee84264 46 // Infinite loop waiting for BLE events
mbedAustin 1:0692bee84264 47 for (;;) {
mbedAustin 8:5442739198ec 48 ble.waitForEvent(); // this saves battery while waiting for callback events
mbedAustin 1:0692bee84264 49 }
mbedAustin 1:0692bee84264 50 }