Would like to ask for assistance with the code below. It's the Adafruit Bluefruit Atmega32U LE module with Adafruit's Arduino IDE example "heart-rate monitor" sketch. The code uses the hardware SPI setup with Adafruit's BLE code between the Atmega32U and the nRF51822 using AT Commands built into a BLE stack by Adafruit.
It works at the same speed in real-time on the PC's Arduino IDE USB serial terminal and also on the Android phone's nRF Connect app or any other BLE app that can read "notifications".
Problem: If remove the module from the PC's USB (thus the serial stopped and only using BLE) the update rate on the BLE Android app slows down to 5 second intervals compared to the near real-time speed while connected to USB. I tried many things, including commenting out the Serial commands in the void loop() and also the delay(), but no change. As if the BLE stack by Adafruit would have a update period limitation. According to Adafruit, they do not give access to to their BLE stack. But I could possibly load another BLE stack on this nRF51822 chip. Also I do have the Adafruit Sniffer with Wireshark, but not an expert using it.
How can I get less than 1 second update rates? The data stream is not in 1 second intervals. Maybe 10-15 seconds between readings, but I need it updated within 1 second of being read from the sensor.
view=allhttps://learn.adafruit.com/adafruit-feather-32u4-bluefruit-le?view=all
#include <Arduino.h>
#include <SPI.h>
#include "Adafruit_BLE.h"
#include "Adafruit_BluefruitLE_SPI.h"
#include "Adafruit_BluefruitLE_UART.h"
#include "BluefruitConfig.h"
#if SOFTWARE_SERIAL_AVAILABLE
#include <SoftwareSerial.h>
#endif
// Create the bluefruit object, either software serial...uncomment these lines
/*
SoftwareSerial bluefruitSS = SoftwareSerial(BLUEFRUIT_SWUART_TXD_PIN, BLUEFRUIT_SWUART_RXD_PIN);
Adafruit_BluefruitLE_UART ble(bluefruitSS, BLUEFRUIT_UART_MODE_PIN,
BLUEFRUIT_UART_CTS_PIN, BLUEFRUIT_UART_RTS_PIN);
*/
/* ...or hardware serial, which does not need the RTS/CTS pins. Uncomment this line */
// Adafruit_BluefruitLE_UART ble(BLUEFRUIT_HWSERIAL_NAME, BLUEFRUIT_UART_MODE_PIN);
/* ...hardware SPI, using SCK/MOSI/MISO hardware SPI pins and then user selected CS/IRQ/RST */
Adafruit_BluefruitLE_SPI ble(BLUEFRUIT_SPI_CS, BLUEFRUIT_SPI_IRQ, BLUEFRUIT_SPI_RST);
/* ...software SPI, using SCK/MOSI/MISO user-defined SPI pins and then user selected CS/IRQ/RST */
//Adafruit_BluefruitLE_SPI ble(BLUEFRUIT_SPI_SCK, BLUEFRUIT_SPI_MISO,
// BLUEFRUIT_SPI_MOSI, BLUEFRUIT_SPI_CS,
// BLUEFRUIT_SPI_IRQ, BLUEFRUIT_SPI_RST);
// A small helper
void error(const __FlashStringHelper*err) {
Serial.println(err);
while (1);
}
/* The service information */
int32_t hrmServiceId;
int32_t hrmMeasureCharId;
int32_t hrmLocationCharId;
/**************************************************************************/
/*!
@brief Sets up the HW an the BLE module (this function is called
automatically on startup)
*/
/**************************************************************************/
void setup(void)
{
while (!Serial); // required for Flora & Micro
delay(500);
boolean success;
Serial.begin(115200);
Serial.println(F("Adafruit Bluefruit Heart Rate Monitor (HRM) Example"));
Serial.println(F("---------------------------------------------------"));
randomSeed(micros());
/* Initialise the module */
Serial.print(F("Initialising the Bluefruit LE module: "));
if ( !ble.begin(VERBOSE_MODE) )
{
error(F("Couldn't find Bluefruit, make sure it's in CoMmanD mode & check wiring?"));
}
Serial.println( F("OK!") );
/* Perform a factory reset to make sure everything is in a known state */
Serial.println(F("Performing a factory reset: "));
if (! ble.factoryReset() ){
error(F("Couldn't factory reset"));
}
/* Disable command echo from Bluefruit */
ble.echo(false);
Serial.println("Requesting Bluefruit info:");
/* Print Bluefruit information */
ble.info();
// this line is particularly required for Flora, but is a good idea
// anyways for the super long lines ahead!
// ble.setInterCharWriteDelay(5); // 5 ms
/* Change the device name to make it easier to find */
Serial.println(F("Setting device name to 'Bluefruit HRM': "));
if (! ble.sendCommandCheckOK(F("AT+GAPDEVNAME=Bluefruit HRM")) ) {
error(F("Could not set device name?"));
}
/* Add the Heart Rate Service definition */
/* Service ID should be 1 */
Serial.println(F("Adding the Heart Rate Service definition (UUID = 0x180D): "));
success = ble.sendCommandWithIntReply( F("AT+GATTADDSERVICE=UUID=0x180D"), &hrmServiceId);
if (! success) {
error(F("Could not add HRM service"));
}
/* Add the Heart Rate Measurement characteristic */
/* Chars ID for Measurement should be 1 */
Serial.println(F("Adding the Heart Rate Measurement characteristic (UUID = 0x2A37): "));
success = ble.sendCommandWithIntReply( F("AT+GATTADDCHAR=UUID=0x2A37, PROPERTIES=0x10, MIN_LEN=2, MAX_LEN=3, VALUE=00-40"), &hrmMeasureCharId);
if (! success) {
error(F("Could not add HRM characteristic"));
}
/* Add the Body Sensor Location characteristic */
/* Chars ID for Body should be 2 */
Serial.println(F("Adding the Body Sensor Location characteristic (UUID = 0x2A38): "));
success = ble.sendCommandWithIntReply( F("AT+GATTADDCHAR=UUID=0x2A38, PROPERTIES=0x02, MIN_LEN=1, VALUE=3"), &hrmLocationCharId);
if (! success) {
error(F("Could not add BSL characteristic"));
}
/* Add the Heart Rate Service to the advertising data (needed for Nordic apps to detect the service) */
Serial.print(F("Adding Heart Rate Service UUID to the advertising payload: "));
ble.sendCommandCheckOK( F("AT+GAPSETADVDATA=02-01-06-05-02-0d-18-0a-18") );
/* Reset the device for the new service setting changes to take effect */
Serial.print(F("Performing a SW reset (service changes require a reset): "));
ble.reset();
Serial.println();
}
/** Send randomized heart rate data continuously **/
void loop(void)
{
int heart_rate = random(50, 100);
//Serial.print(F("Updating HRM value to "));
//Serial.print(heart_rate);
// Serial.println(F(" BPM"));
/* Command is sent when \n (\r) or println is called */
/* AT+GATTCHAR=CharacteristicID,value */
ble.print( F("AT+GATTCHAR=") );
ble.print( hrmMeasureCharId );
ble.print( F(",00-") );
ble.println(heart_rate, HEX);
/* Check if command executed OK */
// if ( !ble.waitForOK() )
// {
// Serial.println(F("Failed to get response!"));
//}
/* Delay before next measurement update */
// delay(1000);
}