UCL IoT
Application for nRF51822 mbed KIT that controls the intensity of LED2 using the BLE UART Service. Works with the Android App BLE_mbed_Remote available here https://github.com/bennthomsen/BLE_mbed_Remote
Dependencies: BLE_API mbed nRF51822
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BLE_UART_LEDControl_Echo
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UCL IoT
This program demonstrates the use of the BLE UART Service to receive and send commands in order to remotely control the operation. In this example the intensity of LED2 can be remotely controlled.
The program accepts commands of the form "led2 0.1" over the BLE UART Service and uses these to set the duty cycle of the PWM Output that is connected to LED2 on the nRF51822 mbed KIT.
An Example Android App is available here https://github.com/bennthomsen/BLE_mbed_Remote. The complete source code and Android Studio Project files are available and can simply be pulled into Android Studio. The App implements sending of text, LED on off Button and a slider to control the LED brightness. At this stage setting the switch to off sets the PWM duty cycle to 0.0, however due to the PWMOut implementation in mbed the LED is not completely off at this point.
Diff: main.cpp
- Revision:
- 13:291a8f177400
- Parent:
- 12:36a9f01cfa0a
- Child:
- 14:8ff3bfb6b19d
--- a/main.cpp Wed Dec 17 19:46:22 2014 +0000
+++ b/main.cpp Wed Dec 17 22:43:40 2014 +0000
@@ -19,7 +19,7 @@
#include "UARTService.h"
-#define NEED_CONSOLE_OUTPUT 0 /* Set this if you need debug messages on the console;
+#define NEED_CONSOLE_OUTPUT 1 /* Set this if you need debug messages on the console;
* it will have an impact on code-size and power consumption. */
#if NEED_CONSOLE_OUTPUT
@@ -28,24 +28,39 @@
#define DEBUG(...) /* nothing */
#endif /* #if NEED_CONSOLE_OUTPUT */
-BLEDevice ble;
-DigitalOut led1(LED1);
+#define LED2OFF "led2 off"
+#define LED2ON "led2 on"
+
+
+//char rxPayload[CMD_SIZE];
+
+BLEDevice ble; // Create Bluetooth object
+DigitalOut led1(LED1); // Set the pin attached to LED1 as an output
+DigitalOut led2(LED2); // Set the pin attached to LED2 as an output
UARTService *uartServicePtr;
+/* BLE disconnected callback */
void disconnectionCallback(Gap::Handle_t handle, Gap::DisconnectionReason_t reason)
{
DEBUG("Disconnected!\n\r");
DEBUG("Restarting the advertising process\n\r");
ble.startAdvertising();
}
-
+/* BLE UART data received callback */
void onDataWritten(const GattCharacteristicWriteCBParams *params)
{
- if ((uartServicePtr != NULL) && (params->charHandle == uartServicePtr->getTXCharacteristicHandle())) {
+ if ((uartServicePtr != NULL) && (params->charHandle == uartServicePtr->getTXCharacteristicHandle())) { //If characters received over BLE
uint16_t bytesRead = params->len;
DEBUG("received %u bytes\n\r", bytesRead);
- ble.updateCharacteristicValue(uartServicePtr->getRXCharacteristicHandle(), params->data, bytesRead);
+ //strncpy(rxPayload, (const char *)params->data, bytesRead);
+ DEBUG("Received string: '");
+ DEBUG((const char *)params->data); //Note the size of data expands to the largest string received. Need to use bytesRead to resize.
+ DEBUG("'\n\r");
+ if (!strncmp(LED2ON,(const char *)params->data,bytesRead)) led2 = 1; // If the received and command string are equal turn led2 on. Note strcmp returns 0 if strings are equal
+ if (!strncmp(LED2OFF,(const char *)params->data,bytesRead)) led2 = 0; // If the received and command string are equal turn led2 off.
+ //Toggle LED2 when data received
+ ble.updateCharacteristicValue(uartServicePtr->getRXCharacteristicHandle(), params->data, bytesRead); // Echo received characters back over BLE
}
}
@@ -58,29 +73,30 @@
int main(void)
{
led1 = 1;
+ led2 = 0;
Ticker ticker; // Create period timer
ticker.attach(periodicCallback, 1); // Attach ticker callback function with a period of 1 second
DEBUG("Initialising the nRF51822\n\r");
ble.init();
- ble.onDisconnection(disconnectionCallback);
- ble.onDataWritten(onDataWritten);
+ ble.onDisconnection(disconnectionCallback); // Define callback function for BLE disconnection event
+ ble.onDataWritten(onDataWritten); // Define callback function for BLE Data received event
/* setup advertising */
- ble.accumulateAdvertisingPayload(GapAdvertisingData::BREDR_NOT_SUPPORTED);
+ ble.accumulateAdvertisingPayload(GapAdvertisingData::BREDR_NOT_SUPPORTED); // Indicate that Legacy Bluetooth in not supported
ble.setAdvertisingType(GapAdvertisingParams::ADV_CONNECTABLE_UNDIRECTED);
ble.accumulateAdvertisingPayload(GapAdvertisingData::SHORTENED_LOCAL_NAME,
(const uint8_t *)"BLE UART", sizeof("BLE UART") - 1);
ble.accumulateAdvertisingPayload(GapAdvertisingData::COMPLETE_LIST_128BIT_SERVICE_IDS,
(const uint8_t *)UARTServiceUUID_reversed, sizeof(UARTServiceUUID_reversed));
- ble.setAdvertisingInterval(Gap::MSEC_TO_ADVERTISEMENT_DURATION_UNITS(1000));
- ble.startAdvertising();
+ ble.setAdvertisingInterval(Gap::MSEC_TO_ADVERTISEMENT_DURATION_UNITS(1000)); // Set advertising interval to 1 second
+ ble.startAdvertising(); // Start advertising
- UARTService uartService(ble);
- uartServicePtr = &uartService;
+ UARTService uartService(ble); // Create BLE UART service
+ uartServicePtr = &uartService; // Initalise pointer to point to UART Service
while (true) {
- ble.waitForEvent();
+ ble.waitForEvent(); // Wait for BLE events
}
}