diff --git a/lcd.h b/lcd.h
index 812084d..c2cd199 100644
--- a/lcd.h
+++ b/lcd.h
@@ -11,6 +11,7 @@
 			uint8_t rows, cols;
 			char* buffer = NULL;
 
+
 		public:
 			LCDWrapper(uint8_t addr, uint8_t cols, uint8_t rows, uint8_t charsize=LCD_5x8DOTS) : LiquidCrystal_I2C(addr,cols,rows,charsize) {
 				this->cols = cols;
@@ -22,20 +23,6 @@
 				LiquidCrystal_I2C::backlight();
 			}
 
-			void printf(const char *fmt, ...){
-				buffer = (char*) malloc( BUFSIZE * sizeof(char*));
-				buffer[0] = 0;
-
-				va_list ap;
-				va_start(ap, fmt);
-				int size = vsnprintf(buffer, BUFSIZE, fmt, ap);
-				va_end(ap);
-				if( size < 0 || size > BUFSIZE ){ free(buffer); return; }
-
-				LiquidCrystal_I2C::print(buffer);
-				free(buffer);
-			}
-
 			void printfn(const uint8_t line, const char *fmt, ...){
 				buffer = (char*) malloc( BUFSIZE * sizeof(char*));
 				buffer[0] = 0;
@@ -44,7 +31,7 @@
 				va_start(ap, fmt);
 				int size = vsnprintf(buffer, BUFSIZE, fmt, ap);
 				va_end(ap);
-				if( size < 0 || size > BUFSIZE ){ free(buffer); return; }
+				if( size < 0 || size >= BUFSIZE ){ free(buffer); return; }
 
 				LiquidCrystal_I2C::setCursor(0, line);
 				LiquidCrystal_I2C::print(buffer);
@@ -59,20 +46,36 @@
 				va_start(ap, fmt);
 				int size = vsnprintf(buffer, BUFSIZE, fmt, ap);
 				va_end(ap);
-				if( size < 0 || size > BUFSIZE ){ free(buffer); return; }
+				buffer[BUFSIZE-1] = 0;
+				if( size < 0 || size >= BUFSIZE ){ free(buffer); return; }
 
-				LiquidCrystal_I2C::setCursor(0, line);
+
+				LiquidCrystal_I2C::setCursor(0,line);
 				LiquidCrystal_I2C::print(buffer);
 				if( size <= cols ){ free(buffer); return; }
 
 				for( uint8_t offset = 1 ; offset <= size-cols ; offset++ ){
 					delay(200);
-
-					LiquidCrystal_I2C::setCursor(0, line);
+					LiquidCrystal_I2C::setCursor(0,line);
 					LiquidCrystal_I2C::print(buffer+offset);
 				}
 				free(buffer);
 			}
+
+		protected:
+			void printf(const char *fmt, ...) {
+				buffer = (char*) malloc( BUFSIZE * sizeof(char*));
+				buffer[0] = 0;
+
+				va_list ap;
+				va_start(ap, fmt);
+				int size = vsnprintf(buffer, BUFSIZE, fmt, ap);
+				va_end(ap);
+				if( size < 0 || size >= BUFSIZE ){ free(buffer); return; }
+
+				LiquidCrystal_I2C::print(buffer);
+				free(buffer);
+			}
 	};
 
 #endif
\ No newline at end of file
diff --git a/node/main/main.ino b/node/main/main.ino
index 080952e..07f2039 100644
--- a/node/main/main.ino
+++ b/node/main/main.ino
@@ -20,10 +20,9 @@ void setup() {
 	Serial.println("+ ready");
 
 	screen.begin();
-	screen.printf("[  node ready  ]");
+	screen.printfn(0, "[  node ready  ]");
 
 	xbee.begin(38400);
-
 	time = millis();
 }
 
@@ -35,7 +34,6 @@ void loop() {
 		send_data();
 	}
 
-
 	/* [2] Listen for incoming data */
 	if( xbee.receive(recv) != XBWRECV_OK )
 		return;
@@ -43,11 +41,11 @@ void loop() {
 	uint8_t opcode = recv.getOpcode();
 
 	// 1. manage discover request
-	if( opcode == 0 )
+	if( opcode == OPCODE_DISCOVER )
 		return manage_discover();
 
 	// 2. manage message data
-	else if( opcode == 1 )
+	else if( opcode == OPCODE_MESSAGE )
 		return manage_message();
 
 
@@ -56,21 +54,19 @@ void loop() {
 void send_data(){
 	Serial.println(" -> message");
 	// 1. prepare message
-	send.setOpcode(1);
+	send.setOpcode(OPCODE_MESSAGE);
+	send.setSender(SENDERID);
 	send.setDist(dist);
 	send.setTTL(MESSAGE_TTL);
-	uint8_t data[32] = {0};
+	char data[64] = {0};
 	strcpy(data, "https://git.xdrm.io");
-	Serial.print("'");
-	Serial.print( (char*) data);
-	Serial.println("'");
-	send.setData(data, strlen(data));
-	send.setSender(SENDERID);
+	send.setData(data);
 
 	// 2. debug
 	screen.clear();
 	screen.printfn(0, "msg[%3d/%3d] %3d", send.getDist(), send.getTTL(), send.getSize());
-	screen.printfn_overflow(1, "%s", send.getData());
+	screen.printfn_overflow(1, "%s", (char*) send.getData());
+	delay(1000);
 
 	// 3. send
 	xbee.broadcast(send);
@@ -79,17 +75,18 @@ void send_data(){
 
 
 void manage_discover(){
-	Serial.println(" <- discover");
-	// security
-	if( recv.getDist() == 0 && recv.getSender() != SENDERID )
-		return;
+	Serial.print(" <- discover[ ");
+	Serial.print(recv.getDist());
+	Serial.print(" / ");
+	Serial.print(recv.getWave());
+	Serial.println(" ]");
 
 	screen.clear();
-	screen.printfn(0, "dsc[%3d] %3d/%3d", recv.getSender(), recv.getDist(), recv.getWave());
+	screen.printfn(0, "dsc[ %3d / %3d ]", recv.getDist(), recv.getWave());
 
 	// ignore if same wave
 	if( recv.getWave() == wave_id ){
-		screen.printfn(1, "x");
+		screen.printfn(1, "x               ");
 		return;
 	}
 
@@ -98,33 +95,44 @@ void manage_discover(){
 	dist    = recv.getDist()+1;
 
 	// propagate wave
-	send.setOpcode(0);
+	send.setOpcode(OPCODE_DISCOVER);
 	send.setWave(wave_id);
 	send.setDist(dist);
-	send.setSender(SENDERID);
 
-	screen.printfn(1, "dsc[%3d] %3d/%3d", send.getSender(), send.getDist(), send.getWave());
+	screen.printfn(1, "dsc[ %3d / %3d ]", send.getDist(), send.getWave());
 	xbee.broadcast(send);
 }
 
 void manage_message(){
-	Serial.println(" <- message");
+	if( recv.getTTL() <= 0 )
+		return;
+
+	Serial.print(" <- message[");
+	Serial.print(recv.getDist());
+	Serial.print("/");
+	Serial.print(recv.getTTL());
+	Serial.print("] ");
+	Serial.print(recv.getSize());
+	Serial.print(" '");
+	Serial.print((char*) recv.getData());
+	Serial.println("'");
+
 	screen.clear();
 	screen.printfn(0, "msg[%3d/%3d] %3d", recv.getDist(), recv.getTTL(), recv.getSize());
-	delay(500);
-	screen.printfn_overflow(0, "%s", recv.getData());
+	screen.printfn_overflow(1, "%s", (char*) recv.getData());
+	delay(1000);
 
 	// ignore
-	if( recv.getTTL() <= 0 || recv.getDist() > dist ){
-		screen.printfn(1, "x");
+	if( recv.getDist() > dist ){
+		screen.printfn(1, "x               ");
 		return;
 	}
 
 	// propagation
-	send.setOpcode(1);
+	send.setOpcode(OPCODE_MESSAGE);
 	send.setTTL(recv.getTTL()-1);
 	send.setDist(dist);
-	send.setData(recv.getData(), recv.getSize());
+	send.setData(recv.getData());
 
 	screen.printfn(1, "msg[%3d/%3d] %3d", send.getDist(), send.getTTL(), send.getSize());
 	xbee.broadcast(send);
diff --git a/packet.cpp b/packet.cpp
index f81f0cf..33cf332 100644
--- a/packet.cpp
+++ b/packet.cpp
@@ -1,10 +1,12 @@
 #include "packet.h"
 
-
+Packet::Packet(){
+	msg.data = malloc(1 * sizeof(char));
+}
 /* PUBLIC
 ----------------------------------------*/
 // builds a packet from raw data and returns the error code
-uint8_t Packet::read(uint8_t buf[], const size_t size){
+uint8_t Packet::read(uint8_t* buf, const size_t size){
 	// 1. fail on invalid size
 	if( size < 1          ) return PKTREAD_EMPTY;
 	if( size > PROTO_SIZE ) return PKTREAD_OVERFLOW;
@@ -18,7 +20,7 @@ uint8_t Packet::read(uint8_t buf[], const size_t size){
 };
 
 // writes the binary representation of the packet
-size_t Packet::write(uint8_t buf[]){
+size_t Packet::write(uint8_t* buf){
 	if( opcode == 0 )
 		return write_discover(buf);
 
@@ -33,8 +35,8 @@ void Packet::setOpcode(uint8_t value) { opcode = value; dsc.opcode = value; msg.
 uint8_t Packet::getWave()           { return dsc.wave; }
 void Packet::setWave(uint8_t value) { dsc.wave = value; }
 
-uint8_t Packet::getSender()           { return (opcode == 0) ? dsc.sender : msg.sender; }
-void Packet::setSender(uint8_t value) { if(opcode == 0) dsc.sender = value; else msg.sender = value; }
+uint8_t Packet::getSender()           { return msg.sender; }
+void Packet::setSender(uint8_t value) { msg.sender = value; }
 
 uint8_t Packet::getDist()           { return (opcode == 0) ? dsc.dist : msg.dist; }
 void Packet::setDist(uint8_t value) { if(opcode == 0) dsc.dist = value; else msg.dist = value; }
@@ -44,14 +46,22 @@ void Packet::setTTL(uint8_t value) { msg.ttl = value; }
 
 uint8_t Packet::getSize()           { return msg.size; }
 
-uint8_t* Packet::getData()                  { return msg.data; }
-void Packet::setData(uint8_t *buffer, uint8_t size) { memcpy(msg.data, buffer, size); msg.size = size; }
+uint8_t* Packet::getData(){ return msg.data; }
+void Packet::setData(uint8_t *buffer) {
+	if( strlen(buffer) >= 255 )
+		return;
+
+	msg.size = strlen(buffer);
+
+	resizeMessage();
+	strcpy(msg.data, buffer);
+}
 
 
 
 /* PRIVATE
 ----------------------------------------*/
-uint8_t Packet::read_discover(uint8_t buf[], const size_t size){
+uint8_t Packet::read_discover(uint8_t *buf, const size_t size){
 	// 1. fail on invalid size
 	if( size != DISCOVER_SIZE )
 		return PKTREAD_INVALID_DISCOVER_FORMAT;
@@ -59,52 +69,52 @@ uint8_t Packet::read_discover(uint8_t buf[], const size_t size){
 	dsc.opcode = buf[0];
 	dsc.wave   = buf[1];
 	dsc.dist   = buf[2];
-	dsc.sender = buf[3];
 
 	return PKTREAD_OK;
 };
 
-uint8_t Packet::read_message(uint8_t buf[], const size_t size){
+
+size_t Packet::write_discover(uint8_t *buf){
+	buf[0] = dsc.opcode;
+	buf[1] = dsc.wave;
+	buf[2] = dsc.dist;
+
+	return 3;
+};
+
+
+uint8_t Packet::read_message(uint8_t *buf, const size_t size){
 	// 1. fail on invalid size
 	if( size < MESSAGE_MIN_SIZE || size > MESSAGE_MAX_SIZE )
 		return PKTREAD_INVALID_MESSAGE_FORMAT;
 
+	// 2. fill values
 	msg.opcode = buf[0];
-	msg.dist   = buf[1];
-	msg.ttl    = buf[2];
-	msg.size   = buf[3];
+	msg.sender = buf[1];
+	msg.dist   = buf[2];
+	msg.ttl    = buf[3];
+	msg.size   = buf[4];
 
 	// 3. check message size
-	if( size - 5 - 1 != msg.size )
+	if( size - 5 != msg.size )
 		return PKTREAD_INVALID_MESSAGE_FORMAT;
 
 	// 4. extract message
-	memcpy(msg.data, buf+4, msg.size);
-
-	// 5. add sender id
-	msg.sender = buf[msg.size+4+1];
+	resizeMessage();
+	strncpy(msg.data, buf+5, msg.size);
 
 	return PKTREAD_OK;
 };
 
-size_t Packet::write_discover(uint8_t buf[]){
-	buf[0] = dsc.opcode;
-	buf[1] = dsc.wave;
-	buf[2] = dsc.dist;
-	buf[3] = dsc.sender;
-
-	return 4;
-};
-
-size_t Packet::write_message(uint8_t buf[]){
+size_t Packet::write_message(uint8_t *buf){
 	buf[0] = msg.opcode;
-	buf[1] = msg.dist;
-	buf[2] = msg.ttl;
-	buf[3] = msg.size;
+	buf[1] = msg.sender;
+	buf[2] = msg.dist;
+	buf[3] = msg.ttl;
+	buf[4] = msg.size;
 
-	memcpy( buf+4, msg.data, msg.size );
+	buf = realloc(buf, (5+msg.size+1)* sizeof(uint8_t));
+	strncpy(buf+5, msg.data, msg.size);
 
-	buf[msg.size+5] = msg.sender;
-
-	return 4 + msg.size;
+	return 5 + msg.size;
 };
\ No newline at end of file
diff --git a/packet.h b/packet.h
index 4da5014..82fe9a4 100644
--- a/packet.h
+++ b/packet.h
@@ -20,17 +20,19 @@
 			struct message  msg;
 
 			// 3. helpers
-			uint8_t read_discover(uint8_t  buf[], const size_t size);
-			uint8_t read_message(uint8_t   buf[], const size_t size);
-			size_t  write_discover(uint8_t buf[]);
-			size_t  write_message(uint8_t  buf[]);
+			uint8_t read_discover(uint8_t*  buf, const size_t size);
+			uint8_t read_message(uint8_t*   buf, const size_t size);
+			size_t  write_discover(uint8_t* buf);
+			size_t  write_message(uint8_t*  buf);
 
 		public:
+
+			Packet();
 			// builds a packet from raw data and returns the status code
-			uint8_t read(uint8_t buf[], const size_t size);
+			uint8_t read(uint8_t* buf, const size_t size);
 
 			// writes the binary representation of the packet returns the size
-			size_t write(uint8_t buf[]);
+			size_t write(uint8_t* buf);
 
 			// GETTERS / SETTERS
 			uint8_t getOpcode();
@@ -51,7 +53,13 @@
 			uint8_t getSize();
 
 			uint8_t* getData();
-			void setData(uint8_t *buffer, uint8_t size);
+			void setData(uint8_t *buffer);
+
+		protected:
+			resizeMessage(){
+				msg.data = realloc(msg.data, (msg.size+1) * sizeof(uint8_t));
+				// memset(msg.data, 0, msg.size+1);
+			}
 
 	};
 
diff --git a/protocol.h b/protocol.h
index 8669eaa..00046ee 100644
--- a/protocol.h
+++ b/protocol.h
@@ -7,56 +7,29 @@
 	#define SENDERID         42
 	#define MESSAGE_TTL      10
 
+	#define OPCODE_DISCOVER 0
+	#define OPCODE_MESSAGE  1
+
 	// discover request (c.f. class node)
-	#define DISCOVER_SIZE    sizeof(uint8_t)*4
+	#define DISCOVER_SIZE    sizeof(uint8_t)*3
 	struct discover {
 		uint8_t opcode; // opcode = 0
 		uint8_t wave;   // id de la wave
 		uint8_t dist;   // current node's distance
-		uint8_t sender; // sender id
 	};
 
 
 	#define MESSAGE_MIN_SIZE sizeof(uint8_t)*5
-	#define MESSAGE_MAX_SIZE sizeof(uint8_t)*5+sizeof(uint8_t)*255
+	#define MESSAGE_MAX_SIZE (5 + 255) * sizeof(uint8_t)
 	struct message {
 		uint8_t opcode; // opcode = 1
+		uint8_t sender; // sender id
 		uint8_t dist;   // distance of the last sender
 		uint8_t ttl;    // time to live default = 10
 		uint8_t size;   // size of message in bytes
 		uint8_t *data;  // actual message
-		uint8_t sender; // sender id
 	};
 
-
 	#define PROTO_SIZE       MESSAGE_MAX_SIZE
-	// A <node> object is held by each node which values are determined thanks
-	// to the DISCOVER requests it receives; each node broadcasts a DISCOVER
-	// request every DISCOVER_TTL milliseconds
-    // class node{
-	// 	private:
-	// 		// unique id of the node : MAC ADDR
-	// 		int id;
-
-	// 		// last received wave id
-	// 		uint8_t last_wave;
-
-	// 		// relative node-distance to the well
-	// 		// WELL                  : dist = 0
-	// 		// NODE1 can reach WELL  : dist = 1
-	// 		// NODE2 can reach NODE1 : dist = 2
-	// 		// and so on...
-	// 		uint8_t dist;
-
-	// 	public:
-
-	// 		// send a discover request
-	// 		bool discover();
-
-	// 		// update the current node according to a (received)
-	// 		// discover request
-	// 		bool update(struct discover dsc);
-    // };
-
 
 #endif
\ No newline at end of file
diff --git a/well/main/main.ino b/well/main/main.ino
index fa826e3..43a7e06 100644
--- a/well/main/main.ino
+++ b/well/main/main.ino
@@ -17,7 +17,7 @@ void setup() {
 	Serial.println("+ ready");
 
 	screen.begin();
-	screen.printf("[  well ready  ]");
+	screen.printfn(0, "[  well ready  ]");
 
 	xbee.begin(38400);
 
@@ -31,13 +31,12 @@ void loop() {
 		time = millis();
 
 		// increment wave id (will overflow from 255 to 0)
-		send.setOpcode(0);
+		send.setOpcode(OPCODE_DISCOVER);
 		send.setWave(++wave_id);
 		send.setDist(0);
-		send.setSender(SENDERID);
 
 		screen.clear();
-		screen.printfn(0, "dsc[%3d] %3d/%3d", send.getSender(), send.getDist(), send.getWave());
+		screen.printfn(0, "dsc[ %3d / %3d ]", send.getDist(), send.getWave());
 
 		if( xbee.broadcast(send) == XBWSEND_OK ) screen.printfn(1, "sent");
 		else                                     screen.printfn(1, "failed");
diff --git a/xbee_wrapper.cpp b/xbee_wrapper.cpp
index 9a764c7..188da3d 100644
--- a/xbee_wrapper.cpp
+++ b/xbee_wrapper.cpp
@@ -49,21 +49,14 @@ uint8_t XBeeWrapper::broadcast(Packet& pkt){
 	XBeeAddress64 bcast = XBeeAddress64(0x00000000, 0x0000FFFF);
 
 	// build payload from packet
-	uint8_t payload[PROTO_SIZE];
+	uint8_t* payload = malloc(6 * sizeof(uint8_t));
 	size_t payload_size = pkt.write(payload);
 
 	// send
 	Tx64Request tx = Tx64Request(bcast, payload, payload_size);
 	xbee.send(tx);
 
-	// // check status
-	// TxStatusResponse txStatus = TxStatusResponse();
-    // xbee.readPacket();
-    // if( xbee.getResponse().isAvailable() ){
-	// 	if( xbee.getResponse().getApiId() == TX_STATUS_RESPONSE ){
-	// 		xbee.getResponse().getTxStatusResponse(txStatus);
-	// 		return txStatus.isSuccess() ? XBWSEND_OK : XBWSEND_ERROR;
-	// 	}
-    // }
+	free(payload);
+
 	return XBWSEND_OK;
 };
\ No newline at end of file