Hello, I am using BLE shield from Redbear Lab v2.1, with nRF 8001 BLE chip on it, with Arduino UNO- how to find connection interval

RE: Hello, I am using BLE shield from Redbear Lab v2.1, with nRF 8001 BLE chip on it, with Arduino UNO- how to find connection interval

Anders Strand — Mon, 07 Dec 2015 10:17:02 GMT

Hello.

It seems that the library has a 64 byte TX buffer. This does not mean that it can send 64 bytes in one packet over BLE. The limit for BLE is 20 bytes/packet (at the moment).

I found the library you are using here. I recommend you to include relevant links in future posts to make is easier for others to help you.

In RBL_services.h, we find the following:

#define GAP_PPCP_MAX_CONN_INT 0x12 /**< Maximum connection interval as a multiple of 1.25 msec , 0xFFFF means no specific value requested */
#define GAP_PPCP_MIN_CONN_INT  0x6 /**< Minimum connection interval as a multiple of 1.25 msec , 0xFFFF means no specific maximum*/

This means that we have worst case connection interval of 22.5 ms, a best case of 7.5 ms. This gives a theoretical throughput between ~21.3 kbps and ~7 kbps. You need 200*10bit = 2 kbps for you application, so this should work.

Can you try to measure how often you use ble_write and ble_do_events, the arduino function micros() should help you with that.

RE: Hello, I am using BLE shield from Redbear Lab v2.1, with nRF 8001 BLE chip on it, with Arduino UNO- how to find connection interval

csj — Fri, 04 Dec 2015 15:50:40 GMT

Yeah. I am using Simple chat, from the BLE controller app of Red bear lab, to send character and see data, if I press 'a', the Arduino starts sending data, if I send b it stops. In the code I have used sprintf and pointers because I am separating the data as individual digits, and sending each digit as 1 byte

#include <SPI.h>
#include <EEPROM.h>
#include <boards.h>
#include <RBL_nRF8001.h>

int analogPin = 3;
int z;
void setup()
{  
    ble_begin();
    Serial.begin(57600);
}
void loop()
{
  if ( ble_available() )
  {     z=ble_read();
        if(z==97)
        {
          bailout:
          while( ble_available()==0 )
          {
            int val= analogRead(analogPin);
            int b[1]={val};
            char msg[100]={0};
            char *p=msg;
            int j;
            if(val<1000) j=3;
            else if(val<100) j=2;
            else if(val<10) j=1;
            else j=4;
           for(int i=0;i<j;i++)
                {
                   sprintf(p +=strlen(p),"%d",b[i]);
                   ble_write(msg[i]);
                }
        ble_do_events();
        }
        z=ble_read();
        if( z==98 )
        {
          ble_do_events();
        }
        else goto bailout;   
    }
    else Serial.print("Failed\n");
    ble_do_events();
 }
ble_do_events();
}

RE: Hello, I am using BLE shield from Redbear Lab v2.1, with nRF 8001 BLE chip on it, with Arduino UNO- how to find connection interval

Anders Strand — Fri, 04 Dec 2015 13:48:55 GMT

Hey.
Can you post you code, and also links to the Arduino library you are using?