user53837: I am trying to send a char array using Arduino Uno board and nRF24L01 modules
Here is the code for both transmitter and receiver:
 #include <SPI.h> //~ #include <TMRh20nRF24L01.h> //~ #include <TMRh20RF24.h>
 #include <nRF24L01.h>
 #include <RF24.h>
 
 
 #define CE_PIN   9
 #define CSN_PIN 10
 
 // NOTE: the "LL" at the end of the constant is "LongLong" type //
 These are the IDs of each of the slaves const uint64_t slaveID[2] =
 {0xE8E8F0F0E1LL, 0xE8E8F0F0E2LL} ;
 
 RF24 radio(CE_PIN, CSN_PIN); // Create a Radio
 
 char 
> dataToSend[64]="e7665072be018b6b58ea9e40cf38553d6dc293cda4c9d94cda6e91ca61b3a073";
 
 unsigned long currentMillis; unsigned long prevMillis; unsigned long
> txIntervalMillis = 1000; int txVal = 0; float ackMessg[2]={1,2}; byte
 ackMessgLen = 4; // NB this 4 is the number of bytes in the 2 ints
 that will be recieved
 
 
 void setup() {
 
    Serial.begin(9600);
     Serial.println("Track Control Starting");
     radio.begin();
     radio.setDataRate( RF24_250KBPS );
     radio.enableAckPayload();
     radio.setRetries(3,5); // delay, count }
 
 //====================
 
 void loop() {
 
     currentMillis = millis();
     if (currentMillis - prevMillis >= txIntervalMillis) {
 
     radio.openWritingPipe(slaveID[0]); // calls the first slave
                                         // there could be a FOR loop to call several slaves in turn
    
     bool rslt;
     rslt = radio.write( dataToSend, sizeof(dataToSend) );
     Serial.print("\nRSLT (1 = success) ");
     Serial.println(rslt);
     Serial.print("Data Sent ");
     Serial.print(dataToSend[0]);
     Serial.print("  ");
     Serial.println(dataToSend[1]);
     if ( radio.isAckPayloadAvailable() ) {
         radio.read(ackMessg,ackMessgLen);
        Serial.print("Acknowledge received: ");
        Serial.print(ackMessg[0]);


 #include <SPI.h>
 #include <nRF24L01.h>
 #include <RF24.h>
 
 
 #define CE_PIN   9
 #define CSN_PIN 10
 
 // NOTE: the "LL" at the end of the constant is "LongLong" type

 const uint64_t   deviceID = 0xE8E8F0F0E1LL; // Define the ID for this slave

int valChange = 1;
 
 RF24 radio(CE_PIN, CSN_PIN);
 
 char  dataReceived[64];
 int ackData[2] = {12,23};
 
 void setup() {
 
     Serial.begin(9600);
     delay(1000);
     Serial.println("Hand Controller Starting");
     radio.begin();
     radio.setDataRate( RF24_250KBPS );
     radio.openReadingPipe(1,deviceID);
     radio.enableAckPayload();
     radio.writeAckPayload(1, ackData, sizeof(ackData));
     radio.startListening();
 }
 
 void loop() {
 
     if ( radio.available() ) {
         radio.read( dataReceived, sizeof(dataReceived) );
          for (int x = 0; x <64; x++) {
       //if (dataReceived[x] < 16) {
       //  Serial.write('0');
     // }
       Serial.print(dataReceived[x]);}
       Serial.println();
         radio.writeAckPayload(1, ackData, sizeof(ackData));
        
         ackData[0] += valChange; // this just increments so you can see that new data is being sent
     }
}


And here is the output that I get

Hand Controller Starting
e7665072be018b6b58ea9e40cf38553d


user53837: TX code 
#include "sha256.h"
#include <Arduino.h>
#include "./printf.h"

#include <SPI.h>
//~ #include <TMRh20nRF24L01.h>
//~ #include <TMRh20RF24.h>
#include <nRF24L01.h>
#include <RF24.h>


#define CE_PIN   9
#define CSN_PIN 10

// NOTE: the "LL" at the end of the constant is "LongLong" type
// These are the IDs of each of the slaves
const uint64_t slaveID = 0xE8E8F0F0E1L  ;

RF24 radio(CE_PIN, CSN_PIN); // Create a Radio

unsigned long currentMillis;
unsigned long prevMillis;
unsigned long txIntervalMillis = 1000;
int txVal = 0;
int ackMessg[6];
byte ackMessgLen = 4; 

uint8_t* hash;
uint8_t copy[32];
void printHash(uint8_t* hash) {
  int i;
  for (i=0; i<32; i++) {
    Serial.print("0123456789abcdef"[hash[i]>>4]);
    Serial.print("0123456789abcdef"[hash[i]&0xf]);
      copy[i]=hash[i];
  }
  Serial.println();
}

void setup() {
  printf_begin();

  uint32_t a;
  unsigned long ms;

  Serial.begin(9600);

  radio.begin();
    radio.setDataRate( RF24_2MBPS );
    radio.enableAckPayload();
    radio.setRetries(3,5); // delay, count

  // SHA tests
  Serial.println("Test: FIPS 180-2 B.1");
  Serial.println("Expect:ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad");
  Serial.print("Result:");
  ms = micros();
  Sha256.init();
  Sha256.print("abc");
  printHash(Sha256.result());
  Serial.println();
  for(int x=0;x<32;x++)
        {   Serial.print(copy[x]);
            Serial.print(" ");  
                                  }
            Serial.println();

  Serial.print(" Hash took : ");
  Serial.print((micros() - ms));
  Serial.println(" micros");
  Serial.println();

  }


void loop() {

  currentMillis = millis();
    if (currentMillis - prevMillis >= txIntervalMillis) {

    radio.openWritingPipe(slaveID); 
    bool rslt,rsltt;
    rslt = radio.write( copy, 32 );

    if ( radio.isAckPayloadAvailable() ) {
        radio.read(ackMessg,ackMessgLen);
        Serial.print("Acknowledge received: ");
        Serial.print(ackMessg[0]);
        Serial.print("  ");
        Serial.println(ackMessg[1]);
    }
    prevMillis = millis();
 }

}

Rx code
// HandController - the slave or the receiver

    // http://tmrh20.github.io/RF24/

    //~ - CONNECTIONS: nRF24L01 Modules See:
    //~ http://arduino-info.wikispaces.com/Nrf24L01-2.4GHz-HowTo
    //~ 1 - GND
    //~ 2 - VCC 3.3V !!! NOT 5V
    //~ 3 - CE to Arduino pin 9
    //~ 4 - CSN to Arduino pin 10
    //~ 5 - SCK to Arduino pin 13
    //~ 6 - MOSI to Arduino pin 11
    //~ 7 - MISO to Arduino pin 12
    //~ 8 - UNUSED

#include <SPI.h>
//~ #include <TMRh20nRF24L01.h>
//~ #include <TMRh20RF24.h>
#include <nRF24L01.h>
#include <RF24.h>

#define CE_PIN   9
#define CSN_PIN 10

// NOTE: the "LL" at the end of the constant is "LongLong" type

const uint64_t   deviceID[2] ={ 0xE8E8F0F0E1LL,0xE8E8F0F0E1LL}; // Define the ID for slaves

int valChange = 1;

RF24 radio(CE_PIN, CSN_PIN);
RF24 radioo(CE_PIN, CSN_PIN);
uint8_t  dataReceived[32];

int ackData[2] = {12,23};

void setup() {

    Serial.begin(9600);
    Serial.println("Hand Controller Starting");
    radio.begin();
    radio.setDataRate( RF24_2MBPS );
    radio.openReadingPipe(1,deviceID[1]);
    radio.enableAckPayload();
    radio.writeAckPayload(1, ackData, sizeof(ackData));
    radio.startListening();

}

void loop() {

 unsigned long startTimer = millis();

    if ( radio.available() ) {
        radio.read( dataReceived, sizeof(dataReceived) );
        radio.writeAckPayload(1, ackData, sizeof(ackData));
        Serial.println();
        //Serial.println(startTimer);
        Serial.println();
        for(int x=0;x<32;x++)
        {Serial.print(dataReceived[x]);
        Serial.print(" ");}}
        ackData[0] += valChange; // this just increments so you can see that new data is being sent

    }

it is fully working now with both outputs on the same size

53837: <p>I am trying to send a char array using Arduino Uno board and nRF24L01 modules</p>
<p>Here is the code for both transmitter and receiver:</p>
<pre><code> #include &lt;SPI.h&gt; //~ #include &lt;TMRh20nRF24L01.h&gt; //~ #include &lt;TMRh20RF24.h&gt;
 #include &lt;nRF24L01.h&gt;
 #include &lt;RF24.h&gt;
 
 
 #define CE_PIN   9
 #define CSN_PIN 10
 
 // NOTE: the &quot;LL&quot; at the end of the constant is &quot;LongLong&quot; type //
 These are the IDs of each of the slaves const uint64_t slaveID[2] =
 {0xE8E8F0F0E1LL, 0xE8E8F0F0E2LL} ;
 
 RF24 radio(CE_PIN, CSN_PIN); // Create a Radio
 
 char 
&gt; dataToSend[64]=&quot;e7665072be018b6b58ea9e40cf38553d6dc293cda4c9d94cda6e91ca61b3a073&quot;;
 
 unsigned long currentMillis; unsigned long prevMillis; unsigned long
&gt; txIntervalMillis = 1000; int txVal = 0; float ackMessg[2]={1,2}; byte
 ackMessgLen = 4; // NB this 4 is the number of bytes in the 2 ints
 that will be recieved
 
 
 void setup() {
 
    Serial.begin(9600);
     Serial.println(&quot;Track Control Starting&quot;);
     radio.begin();
     radio.setDataRate( RF24_250KBPS );
     radio.enableAckPayload();
     radio.setRetries(3,5); // delay, count }
 
 //====================
 
 void loop() {
 
     currentMillis = millis();
     if (currentMillis - prevMillis &gt;= txIntervalMillis) {
 
     radio.openWritingPipe(slaveID[0]); // calls the first slave
                                         // there could be a FOR loop to call several slaves in turn
    
     bool rslt;
     rslt = radio.write( dataToSend, sizeof(dataToSend) );
     Serial.print(&quot;\nRSLT (1 = success) &quot;);
     Serial.println(rslt);
     Serial.print(&quot;Data Sent &quot;);
     Serial.print(dataToSend[0]);
     Serial.print(&quot;  &quot;);
     Serial.println(dataToSend[1]);
     if ( radio.isAckPayloadAvailable() ) {
         radio.read(ackMessg,ackMessgLen);
        Serial.print(&quot;Acknowledge received: &quot;);
        Serial.print(ackMessg[0]);
</code></pre>
<blockquote>
<pre><code> #include &lt;SPI.h&gt;
 #include &lt;nRF24L01.h&gt;
 #include &lt;RF24.h&gt;
 
 
 #define CE_PIN   9
 #define CSN_PIN 10
 
 // NOTE: the &quot;LL&quot; at the end of the constant is &quot;LongLong&quot; type

 const uint64_t   deviceID = 0xE8E8F0F0E1LL; // Define the ID for this slave

int valChange = 1;
 
 RF24 radio(CE_PIN, CSN_PIN);
 
 char  dataReceived[64];
 int ackData[2] = {12,23};
 
 void setup() {
 
     Serial.begin(9600);
     delay(1000);
     Serial.println(&quot;Hand Controller Starting&quot;);
     radio.begin();
     radio.setDataRate( RF24_250KBPS );
     radio.openReadingPipe(1,deviceID);
     radio.enableAckPayload();
     radio.writeAckPayload(1, ackData, sizeof(ackData));
     radio.startListening();
 }
 
 void loop() {
 
     if ( radio.available() ) {
         radio.read( dataReceived, sizeof(dataReceived) );
          for (int x = 0; x &lt;64; x++) {
       //if (dataReceived[x] &lt; 16) {
       //  Serial.write('0');
     // }
       Serial.print(dataReceived[x]);}
       Serial.println();
         radio.writeAckPayload(1, ackData, sizeof(ackData));
        
         ackData[0] += valChange; // this just increments so you can see that new data is being sent
     }
}
</code></pre>
</blockquote>
<p>And here is the output that I get</p>
<blockquote>
<p>Hand Controller Starting</p>
<p>e7665072be018b6b58ea9e40cf38553d</p>
</blockquote>
 53837: <p>TX code </p>

<pre><code>#include "sha256.h"
#include &lt;Arduino.h&gt;
#include "./printf.h"

#include &lt;SPI.h&gt;
//~ #include &lt;TMRh20nRF24L01.h&gt;
//~ #include &lt;TMRh20RF24.h&gt;
#include &lt;nRF24L01.h&gt;
#include &lt;RF24.h&gt;


#define CE_PIN   9
#define CSN_PIN 10

// NOTE: the "LL" at the end of the constant is "LongLong" type
// These are the IDs of each of the slaves
const uint64_t slaveID = 0xE8E8F0F0E1L  ;

RF24 radio(CE_PIN, CSN_PIN); // Create a Radio

unsigned long currentMillis;
unsigned long prevMillis;
unsigned long txIntervalMillis = 1000;
int txVal = 0;
int ackMessg[6];
byte ackMessgLen = 4; 

uint8_t* hash;
uint8_t copy[32];
void printHash(uint8_t* hash) {
  int i;
  for (i=0; i&lt;32; i++) {
    Serial.print("0123456789abcdef"[hash[i]&gt;&gt;4]);
    Serial.print("0123456789abcdef"[hash[i]&amp;0xf]);
      copy[i]=hash[i];
  }
  Serial.println();
}

void setup() {
  printf_begin();

  uint32_t a;
  unsigned long ms;

  Serial.begin(9600);

  radio.begin();
    radio.setDataRate( RF24_2MBPS );
    radio.enableAckPayload();
    radio.setRetries(3,5); // delay, count

  // SHA tests
  Serial.println("Test: FIPS 180-2 B.1");
  Serial.println("Expect:ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad");
  Serial.print("Result:");
  ms = micros();
  Sha256.init();
  Sha256.print("abc");
  printHash(Sha256.result());
  Serial.println();
  for(int x=0;x&lt;32;x++)
        {   Serial.print(copy[x]);
            Serial.print(" ");  
                                  }
            Serial.println();

  Serial.print(" Hash took : ");
  Serial.print((micros() - ms));
  Serial.println(" micros");
  Serial.println();

  }


void loop() {

  currentMillis = millis();
    if (currentMillis - prevMillis &gt;= txIntervalMillis) {

    radio.openWritingPipe(slaveID); 
    bool rslt,rsltt;
    rslt = radio.write( copy, 32 );

    if ( radio.isAckPayloadAvailable() ) {
        radio.read(ackMessg,ackMessgLen);
        Serial.print("Acknowledge received: ");
        Serial.print(ackMessg[0]);
        Serial.print("  ");
        Serial.println(ackMessg[1]);
    }
    prevMillis = millis();
 }

}
</code></pre>

<p>Rx code</p>

<pre><code>// HandController - the slave or the receiver

    // http://tmrh20.github.io/RF24/

    //~ - CONNECTIONS: nRF24L01 Modules See:
    //~ http://arduino-info.wikispaces.com/Nrf24L01-2.4GHz-HowTo
    //~ 1 - GND
    //~ 2 - VCC 3.3V !!! NOT 5V
    //~ 3 - CE to Arduino pin 9
    //~ 4 - CSN to Arduino pin 10
    //~ 5 - SCK to Arduino pin 13
    //~ 6 - MOSI to Arduino pin 11
    //~ 7 - MISO to Arduino pin 12
    //~ 8 - UNUSED

#include &lt;SPI.h&gt;
//~ #include &lt;TMRh20nRF24L01.h&gt;
//~ #include &lt;TMRh20RF24.h&gt;
#include &lt;nRF24L01.h&gt;
#include &lt;RF24.h&gt;

#define CE_PIN   9
#define CSN_PIN 10

// NOTE: the "LL" at the end of the constant is "LongLong" type

const uint64_t   deviceID[2] ={ 0xE8E8F0F0E1LL,0xE8E8F0F0E1LL}; // Define the ID for slaves

int valChange = 1;

RF24 radio(CE_PIN, CSN_PIN);
RF24 radioo(CE_PIN, CSN_PIN);
uint8_t  dataReceived[32];

int ackData[2] = {12,23};

void setup() {

    Serial.begin(9600);
    Serial.println("Hand Controller Starting");
    radio.begin();
    radio.setDataRate( RF24_2MBPS );
    radio.openReadingPipe(1,deviceID[1]);
    radio.enableAckPayload();
    radio.writeAckPayload(1, ackData, sizeof(ackData));
    radio.startListening();

}

void loop() {

 unsigned long startTimer = millis();

    if ( radio.available() ) {
        radio.read( dataReceived, sizeof(dataReceived) );
        radio.writeAckPayload(1, ackData, sizeof(ackData));
        Serial.println();
        //Serial.println(startTimer);
        Serial.println();
        for(int x=0;x&lt;32;x++)
        {Serial.print(dataReceived[x]);
        Serial.print(" ");}}
        ackData[0] += valChange; // this just increments so you can see that new data is being sent

    }
</code></pre>

<p>it is fully working now with both outputs on the same size</p>
