Bluetooth LTE RN4020 with Software Serial and Arduino to Peripheral

howdy all!
i found tricky find decent documentation of full arduino example using rn 4020 board , explaining everything. made one.

i had other tricky parts made using tricky, demonstrate how use software serial, , how pair peripheral bluetooth heart rate monitor!

i documented in code, , have step-by-step details

lemme know if have better suggestions or whatnot. stuff until things work, , wanted share!

most updated at:
https://github.com/comingle/comingle_example_sketches/tree/master/mod/bluetooth/bluetooth_readheartrate

code: [select]


/*
bluetooth lte 4.0 rn4020 dilduino (arduino) example
2015-04-06
{♥} comingle -by a. quitmeyer
share alike please, tossing public domain

this example shows how running bt 4.0
and how go through sorts of other tricky processes like

** connecting rn 4020 module
** doing on software serial instead of hardware serial
** pairing peripheral (bt heart rate monitor)
** getting notifications of data peripheral

what's bt?
it's weird fancy new bt that, newer phones have (my comp don't have) , operates posting , sending services
more regular serial. there's tricky stuff that's not too
well documented yet, helps out that!
general documentation tom igoe here: https://github.com/tigoe/bledocs/wiki/introduction-to-bluetooth-le


 */

//this example won't use ossex
//#include <ossex.h>

#include <softwareserial.h>

//this software serial ports on dilduino (like leonardo)
softwareserial myserial(15, 14); // rx (15 has rx), tx

int led = 13;

byte byteread;
char mychar ;

void setup()
{
  //set mux on dilduino in serial mode
  pinmode(8, output);
  pinmode(12, output);
  digitalwrite(8, low);
  digitalwrite(12, high);

  //no ossex none of these below
  //  toy.setid(beta);
  //  toy.sethackerport(hacker_port_serial);
  //

  //setup serials

  //hardware serial (uart)
  //we need same soft serial or else doesn't work me
  serial.begin(115200);

  // set data rate softwareserial port
  myserial.begin(115200); //default rate of bluetooth rn4020 115200, changed more reliable data on software serial

  //there's chance might need run commands first time setting 115200 since default
  /*
  initialize bluetooth baud lower speed software serial
    myserial.begin(115200); //default rate of bluetooth rn4020 115200,
    delay(500);
    myserial.println("sb,0"); // 0 = 2400 baud   1 = 9600 baud  2= 19200 baud   4 = 115200 baud (default)
        delay(500);
      myserial.println("r,1"); //reboot
  delay(1000);

  */

  //always nice let chill bit
  delay(1000);

  //bluetooth setup
  //initialize bt rn4020
  
     myserial.println("sb,0"); // 0 = 2400 baud   1 = 9600 baud  2= 19200 baud   4 = 115200 baud (default)
        delay(500);
      myserial.println("r,1"); //reboot
  delay(1000);

  //set central or peripheral device
  //myserial.println("sr,20000000"); //set device in peripheral mode , set turn on auto advertising
  myserial.println("sr,92000000");// set device central, support mldp , enable
  delay(500);

//change name that's displayed, first thing check in debugging
  myserial.println("s-,comingleizcool");
  delay(500);

//reboot sucker make changes stick. light should turn off when reboot (also debugging)
  myserial.println("r,1"); //reboot
  delay(1000);
  
  //make device show on scanners
  myserial.println("a"); //start advertising
  delay(500);
  
  //list details buetooth device (what it's connected to, it's mac address, etc.
  myserial.println("d"); //get details of rn4020 chip's current status


  pinmode(led, output);

}

void loop()
{
  
  
  //this code below let on arduino's software serial talk hardware serial
  //so can see through
  while (myserial.available()) {
    mychar = myserial.read();
    serial.print(mychar);
  }
  //  delay(500);              // wait second

  while (serial.available()) {
    mychar = serial.read();
    myserial.print(mychar);
  }
}





note: here's code chopped out of post meet character limit requirements.

this shows messages send things connecting, , subscribing notifications, , parsing data.

code: [select]


/*
//if works out well, @ point should have device setup
//for issuing , recieveing commands on serial monitor
//to test if things working
//type "d" , hit enter on serial monitor

this gives dump of details of bluetooth chips status

  6c:94:f8:df:f2:75  /mac address
  comingleizcool  //name set
  central // role set
  connected: no  //
  bonded: no
  server services: 80000000
  
 
 if getting that, work, things seem communicating, let's try
 more advanced stuff next
 

*/

/*
-----------------------------
connecting , getting information
-----------------------------



  how connect bt
  type command
  
        f
  
  this starts scanning nearby bluetooth things
  it list mac addresses , stuff
  
when see correct device
use "e" command connect it
my bt heart rate monitor's device number fe9693ddab49
so typed in connect

       e,1,fe9693ddab49 // connect
       //*note if doesn't work try e,0, fe9693ddab49
       //this has "random" , "public" address types
  
  
  once connected
  you can @ different information connected device can offer
  by sending command

        lc

this lists client services
you looks returned on serial
  
  180d // stuff heart rate monitor
    2a37,000b,00
    2a37,000c,02
    2a38,000e,10
    2a39,0010,08
  180f // stuff battery
    2a19,0018,02
    2a19,0019,10
    
    
 this looks bunch of crazy garbage, it's how bluetooth 4.0 shares data
 data gets posted little bulletin areas. , there "official" numbers
 designate types of data
 
"180f" instance battery  state on bt device
"180d" official designation heart rate information (you can these online)

the indented lines below different messages available service.

these messages have specific styles of reading information tied each of them

if want read data characteristic, has end in "02"
for instance, can @ battery status , see "0018" ends "02"
to read on rn4020
type

       chr,0018

and message says:
        
        r,64  //(which showss 100% battery life in hexadecimal)


for more advanced information, heart rate, have subscribe notified of data
data notify ends in "10"

so heart rate (bpm) nice cheap bt heart rate monitor
(you can clones of polar's h7 $15-25)
do this

      chw,000e,0100
      
      
  it sends notify messages this
      
      notify,000e,0054

the last number there hexadecimal heart rate


here's rough example of doing data
we can convert human numbers


int bpm;
string str;
string valstring;

while (myserial.available()) {
  
  str = myserial.readstringuntil('\n');
  
  if(str.startswith("notify,000e"){ //make sure 1 targetting
  
  valstring =  getstringpartbynr(str, ',', 2));  // third part - 0054

bpm =  hextodec(valstring);


  }

}





//function split tokens
// https://github.com/bentommye/arduino_getstringpartbynr/blob/master/getstringpartbynr.ino
//
string getstringpartbynr(string data, char separator, int index)
{
    // spliting string , return part nr index
    // split separator
    
    int stringdata = 0;        //variable count data part nr
    string datapart = "";      //variable hole return text
    
    for(int = 0; i<data.length()-1; i++) {    //walk through text 1 letter @ time
      
      if(data[i]==separator) {
        //count number of times separator character appears in text
        stringdata++;
        
      }else if(stringdata==index) {
        //get text when separator rignt one
        datapart.concat(data[i]);
        
      }else if(stringdata>index) {
        //return text , stop if next separator appears - save cpu-time
        return datapart;
        break;
        
      }

    }
    //return text if last part
    return datapart;
}


// converting hex decimal:

// note: function can handle positive hex value 0 - 65,535 (a 4 digit hex string).
//       larger/longer values, change "unsigned int" "long" in both places.
// https://github.com/benrugg/arduino-hex-decimal-conversion/blob/master/hex_dec.ino


unsigned int hextodec(string hexstring) {
  
  unsigned int decvalue = 0;
  int nextint;
  
  for (int = 0; < hexstring.length(); i++) {
    
    nextint = int(hexstring.charat(i));
    if (nextint >= 48 && nextint <= 57) nextint = map(nextint, 48, 57, 0, 9);
    if (nextint >= 65 && nextint <= 70) nextint = map(nextint, 65, 70, 10, 15);
    if (nextint >= 97 && nextint <= 102) nextint = map(nextint, 97, 102, 10, 15);
    nextint = constrain(nextint, 0, 15);
    
    decvalue = (decvalue * 16) + nextint;
  }
  
  return decvalue;
}



  */



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