I have a project where i am trying to connect two arduino MKR wifi 1010's using bluetooth low energy. One arduino is used as a central, the other one is peripheral. I am able to use the examples codes (LedControl, LED) from arduinoBLE library with no problem. But i want to upgrade them a bit, example, i would like to add another switch to the central device to control the LED on the peripheral. This is my central device's code, it is modified version from LedControl. For some reason the other button does nothing, it does not print anything to serial monitor either?
/*
LED Control
This example scans for Bluetooth® Low Energy peripherals until one with the advertised service
"19b10000-e8f2-537e-4f6c-d104768a1214" UUID is found. Once discovered and connected,
it will remotely control the Bluetooth® Low Energy peripheral's LED, when the button is pressed or released.
The circuit:
- Arduino MKR WiFi 1010, Arduino Uno WiFi Rev2 board, Arduino Nano 33 IoT,
Arduino Nano 33 BLE, or Arduino Nano 33 BLE Sense board.
- Button with pull-up resistor connected to pin 2.
You can use it with another board that is compatible with this library and the
Peripherals -> LED example.
This example code is in the public domain.
*/
//7.11.22
//Testataan yhden charrun ohjausta kahdella tapaa, kytkimellä ja pir-sensorilla.
//Aiemmat koodit eivät toimi?
#include <ArduinoBLE.h>
// variables for button
const int buttonPin = 2;
int oldButtonState = LOW;
const int buttonPin2 = 3;
int oldButtonState2 = LOW;
void setup() {
Serial.begin(9600);
while (!Serial);
// configure the button pin as input
pinMode(buttonPin, INPUT);
pinMode(buttonPin2, INPUT);
// initialize the Bluetooth® Low Energy hardware
BLE.begin();
Serial.println("Bluetooth® Low Energy Central - LED control");
// start scanning for peripherals
BLE.scanForUuid("19B10000-E8F2-537E-4F6C-D104768A1214");
}
void loop() {
// check if a peripheral has been discovered
BLEDevice peripheral = BLE.available();
if (peripheral) {
// discovered a peripheral, print out address, local name, and advertised service
Serial.print("Found ");
Serial.print(peripheral.address());
Serial.print(" '");
Serial.print(peripheral.localName());
Serial.print("' ");
Serial.print(peripheral.advertisedServiceUuid());
Serial.println();
if (peripheral.localName() != "LED") {
return;
}
// stop scanning
BLE.stopScan();
controlLed(peripheral);
// peripheral disconnected, start scanning again
BLE.scanForUuid("19B10000-E8F2-537E-4F6C-D104768A1214");
}
}
void controlLed(BLEDevice peripheral) {
// connect to the peripheral
Serial.println("Connecting ...");
if (peripheral.connect()) {
Serial.println("Connected");
} else {
Serial.println("Failed to connect!");
return;
}
// discover peripheral attributes
Serial.println("Discovering attributes ...");
if (peripheral.discoverAttributes()) {
Serial.println("Attributes discovered");
} else {
Serial.println("Attribute discovery failed!");
peripheral.disconnect();
return;
}
// retrieve the LED characteristic
BLECharacteristic ledCharacteristic = peripheral.characteristic("19b10001-e8f2-537e-4f6c-d104768a1214");
if (!ledCharacteristic) {
Serial.println("Peripheral does not have LED characteristic!");
peripheral.disconnect();
return;
} else if (!ledCharacteristic.canWrite()) {
Serial.println("Peripheral does not have a writable LED characteristic!");
peripheral.disconnect();
return;
}
//In this while loop im trying to control the peripheral device's build-in LED with two switches
while (peripheral.connected()) {
// while the peripheral is connected
// read the button pin
int buttonState = digitalRead(buttonPin);
int buttonState2 = digitalRead(buttonPin2);
if (oldButtonState != buttonState) {
// button changed
oldButtonState = buttonState;
if (buttonState) {
Serial.println("button pressed");
// button is pressed, write 0x01 to turn the LED on
ledCharacteristic.writeValue((byte)0x01);
} else {
Serial.println("button released");
// button is released, write 0x00 to turn the LED off
ledCharacteristic.writeValue((byte)0x00);
}
//button 2
if (oldButtonState2 != buttonState2) {
// button changed
oldButtonState2 = buttonState2;
if (buttonState2) {
Serial.println("button pressed");
// button is pressed, write 0x01 to turn the LED on
ledCharacteristic.writeValue((byte)0x01);
} else {
Serial.println("button released");
// button is released, write 0x00 to turn the LED off
ledCharacteristic.writeValue((byte)0x00);
}
}
}
//This did not work
/*while (peripheral.connected()) {
// while the peripheral is connected
// read the button pin
int buttonState2 = digitalRead(buttonPin2);
if (oldButtonState2 != buttonState2) {
// button changed
oldButtonState2 = buttonState2;
if (buttonState2) {
Serial.println("button pressed");
// button is pressed, write 0x01 to turn the LED on
ledCharacteristic.writeValue((byte)0x01);
} else {
Serial.println("button released");
// button is released, write 0x00 to turn the LED off
ledCharacteristic.writeValue((byte)0x00);
}
}
}
*/
// Serial.println("Peripheral disconnected");
}
}
Here is the peripheral's code, it's just the original LED-example
The circuit:
- Arduino MKR WiFi 1010, Arduino Uno WiFi Rev2 board, Arduino Nano 33 IoT,
Arduino Nano 33 BLE, or Arduino Nano 33 BLE Sense board.
You can use a generic Bluetooth® Low Energy central app, like LightBlue (iOS and Android) or
nRF Connect (Android), to interact with the services and characteristics
created in this sketch.
This example code is in the public domain.
*/
#include <ArduinoBLE.h>
BLEService ledService("19B10000-E8F2-537E-4F6C-D104768A1214"); // Bluetooth® Low Energy LED Service
// Bluetooth® Low Energy LED Switch Characteristic - custom 128-bit UUID, read and writable by central
BLEByteCharacteristic switchCharacteristic("19B10001-E8F2-537E-4F6C-D104768A1214", BLERead | BLEWrite);
const int ledPin = LED_BUILTIN; // pin to use for the LED
void setup() {
Serial.begin(9600);
while (!Serial);
// set LED pin to output mode
pinMode(ledPin, OUTPUT);
// begin initialization
if (!BLE.begin()) {
Serial.println("starting Bluetooth® Low Energy module failed!");
while (1);
}
// set advertised local name and service UUID:
BLE.setLocalName("LED");
BLE.setAdvertisedService(ledService);
// add the characteristic to the service
ledService.addCharacteristic(switchCharacteristic);
// add service
BLE.addService(ledService);
// set the initial value for the characeristic:
switchCharacteristic.writeValue(0);
// start advertising
BLE.advertise();
Serial.println("BLE LED Peripheral");
}
void loop() {
// listen for Bluetooth® Low Energy peripherals to connect:
BLEDevice central = BLE.central();
// if a central is connected to peripheral:
if (central) {
Serial.print("Connected to central: ");
// print the central's MAC address:
Serial.println(central.address());
// while the central is still connected to peripheral:
while (central.connected()) {
// if the remote device wrote to the characteristic,
// use the value to control the LED:
if (switchCharacteristic.written()) {
if (switchCharacteristic.value()) { // any value other than 0
Serial.println("LED on");
digitalWrite(ledPin, HIGH); // will turn the LED on
} else { // a 0 value
Serial.println(F("LED off"));
digitalWrite(ledPin, LOW); // will turn the LED off
}
}
}
// when the central disconnects, print it out:
Serial.print(F("Disconnected from central: "));
Serial.println(central.address());
}
}