error message in order to connect arduino in bluetooth - error-handling

Question

(sorry for bad english)
I try to display the accelerometer data (x,y,z) from my arduino (33 ble sense) to my phone via bluetooth.
This is a project for school : it will be a hit captor for a boxer (put on a punching bag). Indeed, it will save the acceleration of the punching bag to finally convert it into "power" of hit .
To finally manage to convert this data into power of an athlete (a boxer) maybe with a function include in the programm later (F=m x acc).
I start with nrF connect for the beggining but i have to create a app with "MIT app inventor" later..
but now my code do not work. My code is here :
#include <ArduinoBLE.h>
#include <Arduino_LSM9DS1.h>
BLEService dataService("180C"); // User defined service
BLEStringCharacteristic dataCharacteristic("2A56", // standard 16-bit characteristic UUID
BLERead | BLENotify, 50); // remote clients will be able to read and subscribe to notifications
float oldX = 0.0; // last value
float oldY = 0.0;
float oldZ = 0.0;
long previousMillis = 0; // last time the value was checked, in ms
void setup()
{
Serial.begin(9600); // initialize serial communication
while (!Serial)
;
pinMode(LED_BUILTIN, OUTPUT); // initialize the built-in LED pin
if (!BLE.begin()) { // initialize BLE
Serial.println("starting BLE failed!");
while (1)
;
}
BLE.setLocalName("Sac de frappe"); // Set name for connection
BLE.setAdvertisedService(dataService); // Advertise service
dataService.addCharacteristic(dataCharacteristic); // Add characteristic to service
BLE.addService(dataService); // Add service
dataCharacteristic.setValue(String(oldX)); // Set data string
BLE.advertise(); // Start advertising
Serial.print("Peripheral device MAC: ");
Serial.println(BLE.address());
Serial.println("Waiting for connections...");
Serial.begin(9600);
while (!Serial);
Serial.println("Started");
if (!IMU.begin()) {
Serial.println("Failed to initialize IMU!");
while (1);
}
Serial.print("Accelerometer sample rate = ");
Serial.print(IMU.accelerationSampleRate());
Serial.println(" Hz");
Serial.println();
Serial.println("Acceleration in G's");
Serial.println("X\tY\tZ");
}
void loop()
{
BLEDevice central = BLE.central(); // Wait for a BLE central to connect
// if a central is connected to the peripheral:
if (central) {
Serial.print("Connected to central MAC: ");
// print the central's BT address:
Serial.println(central.address());
// turn on the LED to indicate the connection:
digitalWrite(LED_BUILTIN, HIGH);
// update value every 200ms
// while the central is connected:
while (central.connected()) {
long currentMillis = millis();
// if 200ms have passed, update value:
if (currentMillis - previousMillis >= 200) {
previousMillis = currentMillis;
updateValue();
}
}
}
// when the central disconnects, turn off the LED:
digitalWrite(LED_BUILTIN, LOW);
Serial.print("Disconnected from central MAC: ");
Serial.println(central.address());
}
void updateValue() {
float x, y, z;
if (!IMU.accelerationAvailable()) return; // Return if not ready
IMU.readAcceleration(x, y, z); // Read new data
if (x != oldX || y != oldY || z != oldZ) {
// print it
Serial.print(x);
Serial.print('\t');
Serial.print(y);
Serial.print('\t');
Serial.println(z);
dataCharacteristic.writeValue("X: " + (String(x)) + " Y: " (String(y)) + " Z: " + (String(z))); // update value
// save the value for next comparison
oldX = x;
oldY = y;
oldZ = z;
}
}
I have an error message : expression cannot be used as a function ... about this line : (void updateValue):
dataCharacteristic.writeValue("X: " + (String(x)) + " Y: " (String(y)) + " Z: " + (String(z))); // update value
and also in this line : (void setup)
dataCharacteristic.setValue(String(oldX)); // Set data string
How am i suppose to put the three value x, y and z ?
I can't fix it ... can you help me please ?
thanks

Answer 1

I already fixed my two mistakes in my answer to your last question
#include <ArduinoBLE.h>
#include <Arduino_LSM9DS1.h>
BLEService dataService("180C"); // User defined service
BLEStringCharacteristic dataCharacteristic("2A56", // standard 16-bit characteristic UUID
BLERead | BLENotify, 50); // remote clients will be able to read and subscribe to notifications
float oldX = 0.0; // last value
float oldY = 0.0;
float oldZ = 0.0;
long previousMillis = 0; // last time the value was checked, in ms
void setup()
{
Serial.begin(9600); // initialize serial communication
while (!Serial)
;
pinMode(LED_BUILTIN, OUTPUT); // initialize the built-in LED pin
if (!BLE.begin()) { // initialize BLE
Serial.println("starting BLE failed!");
while (1)
;
}
BLE.setLocalName("Sac de frappe"); // Set name for connection
BLE.setAdvertisedService(dataService); // Advertise service
dataService.addCharacteristic(dataCharacteristic); // Add characteristic to service
BLE.addService(dataService); // Add service
dataCharacteristic.setValue(""); // Set initial value
BLE.advertise(); // Start advertising
Serial.print("Peripheral device MAC: ");
Serial.println(BLE.address());
Serial.println("Waiting for connections...");
Serial.begin(9600);
while (!Serial);
Serial.println("Started");
if (!IMU.begin()) {
Serial.println("Failed to initialize IMU!");
while (1);
}
Serial.print("Accelerometer sample rate = ");
Serial.print(IMU.accelerationSampleRate());
Serial.println(" Hz");
Serial.println();
Serial.println("Acceleration in G's");
Serial.println("X\tY\tZ");
}
void loop()
{
BLEDevice central = BLE.central(); // Wait for a BLE central to connect
// if a central is connected to the peripheral:
if (central) {
Serial.print("Connected to central MAC: ");
// print the central's BT address:
Serial.println(central.address());
// turn on the LED to indicate the connection:
digitalWrite(LED_BUILTIN, HIGH);
// update value every 200ms
// while the central is connected:
while (central.connected()) {
long currentMillis = millis();
// if 200ms have passed, update value:
if (currentMillis - previousMillis >= 200) {
previousMillis = currentMillis;
updateValue();
}
}
}
// when the central disconnects, turn off the LED:
digitalWrite(LED_BUILTIN, LOW);
Serial.print("Disconnected from central MAC: ");
Serial.println(central.address());
}
void updateValue() {
float x, y, z;
if (!IMU.accelerationAvailable()) return; // Return if not ready
IMU.readAcceleration(x, y, z); // Read new data
if (x != oldX || y != oldY || z != oldZ) {
// print it
Serial.print(x);
Serial.print('\t');
Serial.print(y);
Serial.print('\t');
Serial.println(z);
dataCharacteristic.writeValue("X: " + String(x) + " Y: " + String(y) + " Z: " + String(z)); // update value
// save the value for next comparison
oldX = x;
oldY = y;
oldZ = z;
}
}