Sending char arry via nRF24L01

Question

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

• Juraj: you get what you send. continue reading
• Amr Ahmed: yes i know that i got what i sent,my question was how to get the full char array as its size is more than payload size
• Amr Ahmed: how can i do that ?
• Amr Ahmed: thank u very much,but the array is generated from a hash function in sha256 library,i just simplified the code here to discuss the concept
• Amr Ahmed: so can i send the unencoded output from the hash function then map it at the receiver side?

Answer 1

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