https://devzone.nordicsemi.com/f/nordic-q-a/1946/how-to-send-a-message-wake-up-from-nrf51822-to-blev4-0-enable-smartphoneI have Nordic nrf51822 BLE device, I would like to develop a system such that whenever nrf51822 turns on it starts to make connection with the other BLE V4.0 enable smartphone device and send a message &#39;Wake up&#39; after that goes to sleep mode, Can youen-USTelligent Community 13Thu, 20 Mar 2014 15:49:44 GMThttps://devzone.nordicsemi.com/thread/8357?ContentTypeID=1Thu, 20 Mar 2014 15:49:44 GMT137ad170-7792-4731-bb38-c0d22fbe4515:99b9c832-72ac-474a-9f81-3d22a3e524e2Ole Morten<p>The only thing a Peripheral can do is to start advertising. It is up to a Central device to scan for such Peripherals, and then connect when it discovers it. If a Central device is not scanning, there is nothing you can do from a Peripheral to trigger this.</p> <p>You may also have use in taking a look at <a href="http://stackoverflow.com/questions/22097079/is-it-possibile-to-wake-up-a-deep-sleep-ble-device-in-android-sdk">this question, which covers the opposite direction</a>. Also, <a href="https://devzone.nordicsemi.com/index.php/what-is-a-client-and-server-in-ble">this question explains the roles in BLE</a>.</p><div style="clear:both;"></div>