BLE 33 as Peripheral fail to write on Server Char

Official Hardware Nano Family Nano 33 BLE Sense
1

Hi,

I'm using a Nano 33 BLE Sense as BLE peripheral (client BLE) which writes every random time (between 60 to 90 seconds) over a BLE GATT Server with 6 characteristics made on a Raspberry Pi3.

Unfortunately, when the BLE 33 Nano connects to the server, can only find two of the four chars that I need. It can write on this two chars (temperature and humidity), while it can't write on pressure and proximity chars). I can't explain why. Also, sometimes - let's say 20% of the times - it fail to discover the GATT server attributes, ending the connection without writing on any chars.

Do you have any idea?

Here you can find my code:

#include <Arduino_HTS221.h>
#include <Arduino_LPS22HB.h>
#include <Arduino_APDS9960.h>
#include <ArduinoBLE.h>

//readings variables
String pressure;
String temperature;
String humidity;
String proximity;

//rand
long randDelay;

void setup() {
Serial.begin(115200);
randomSeed(analogRead(0));

// initialize the BLE hardware
BLE.begin();

// Sensor Init
if (!HTS.begin()) {
Serial.println("Failed to initialize humidity temperature sensor!");
while (1);
}
if (!BARO.begin()) {
Serial.println("Failed to initialize pressure sensor!");
while (1);
}
if (!APDS.begin()) {
Serial.println("Error initializing APDS9960 sensor!");
}

//Configure WDT.
NRF_WDT->CONFIG = 0x01; // Configure WDT to run when CPU is asleep
NRF_WDT->CRV = 2359296; // CRV = timeout * 32768 + 1
NRF_WDT->RREN = 0x01; // Enable the RR[0] reload register
NRF_WDT->TASKS_START = 1; // Start WDT
}

void loop() {
// start scanning for peripherals
BLE.scanForUuid("c8e459b1-85b8-4816-99b4-3c1a34b53437");
// check if a peripheral has been discovered
BLEDevice peripheral = BLE.available();

// Reload the WDTs RR[0] reload register
NRF_WDT->RR[0] = WDT_RR_RR_Reload;

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();

// stop scanning
BLE.stopScan();

// write data to the right characteritcs
writeReadings(peripheral);
randDelay = random(60, 90);
Serial.println(randDelay);
delay(randDelay*1000);
}
}

void exploreCharacteristic(BLECharacteristic characteristic) {
// print the UUID and properties of the characteristic
Serial.print("\tCharacteristic ");
Serial.print(characteristic.uuid());
Serial.print(", properties 0x");
Serial.print(characteristic.properties(), HEX);

// check if the characteristic is readable
if (characteristic.canRead()) {
// read the characteristic value
characteristic.read();

if (characteristic.valueLength() > 0) {
// print out the value of the characteristic
Serial.print(", value 0x");
printData(characteristic.value(), characteristic.valueLength());
}
}
Serial.println();
}

void printData(const unsigned char data[], int length) {
for (int i = 0; i < length; i++) {
unsigned char b = data*;*

  • if (b < 16) {*

  • Serial.print("0");*

  • }*

  • Serial.print(b, HEX);*

  • }*
    }
    void writeReadings(BLEDevice peripheral) {

  • // connect to the peripheral*

  • Serial.println("Connecting ...");*

  • // check if connected*

  • 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 data characteristics*

  • BLECharacteristic tempChar = peripheral.characteristic("460240d0-e610-4fd5-8a95-a885a30f0660");*

  • delay(50);*

  • BLECharacteristic humChar = peripheral.characteristic("460240d0-e610-4fd5-8a95-a885a30f0661");*

  • delay(50);*

  • BLECharacteristic prChar = peripheral.characteristic("460240d0-e610-4fd5-8a95-a175a30f0662");*

  • delay(50);*

  • BLECharacteristic prxChar = peripheral.characteristic("460240d0-e610-4fd5-8a95-a175a30f0665");*

  • delay(50);*

  • if (peripheral.connected()) {*

  • //Read from sensors*

  • pressure = String(BARO.readPressure());*

  • temperature = String(HTS.readTemperature());*

  • humidity = String(HTS.readHumidity());*

  • proximity = String(APDS.readProximity());*

  • // print readings*

  • Serial.println("Last read was: T="+temperature+" C, RH="+humidity+" %, Pr="+pressure+" kPa, Proximity="+proximity);*

  • //exploreCharacteristic(humChar);*

  • //exploreCharacteristic(prxChar);*

  • // update Char value*

  • tempChar.writeValue(temperature.c_str());*

  • delay(50);*

  • humChar.writeValue(humidity.c_str());*

  • delay(50);*

  • prChar.writeValue(pressure.c_str());*

  • delay(50);*

  • prxChar.writeValue(proximity.c_str());*

  • delay(50);*

  • }*

  • peripheral.disconnect();*

  • Serial.println("Peripheral disconnected");*
    }
    [/quote]
    The server has no Issues, since I can write on it on all GATT chars using one ESP32 and my mobile Phone
    Thank you

2

What do you use as BLE server on your Raspberry Pi? If it is something quick to setup I could run some tests.