LTTO (Lazertag) protocol decoder

Decodes LTTO lazertag protocol.
See wiki.lazerswarm.com for details on how to use.

Author: rmick

ir_LTTO.cpp

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+/*
+ Written by rmick (www.bushandbeyond.com.au) Oct 2017
+ 
+ LTTO means Lazer Tag Team Ops. It is a brand of Lazertag that started life in 2004, from a toy dev company called 'Shoot The Moon'.
+ It was was originally sold under the Tiger brand, then later under Nerf and Hasbro.
+ 
+ The range of taggers supported by this library includes;
+ LTTO/Deluxe
+ IRT-2X drone
+ LTX/Phoenix
+ TMB
+ LTAR
+ 
+ The protocol uses a 38kHz carrier with a 1mS Mark and 2mS Space bits. The Header consists of a 3mS Mark, followed by a 3mS or 6mS Space.
+ 
+ This decoder would not have been possible without the help of many people, inlcuding Riley McArdle, TagFerret & Ryan Bales.
+ 
+ For more information on the protocol and how to use it, please visit
+ 
+ https://wiki.lazerswarm.com/wiki/Main_Page
+ 
+ or ask to join the Lazertag Modders group on Facebook.
+ https://www.facebook.com/groups/LazerTagModders/
+*/
+
+#include "IRremote.h"
+#include "IRremoteInt.h"
+
+//==============================================================================
+//                          L      TTTTT  TTTTT   OOO
+//                          L        T		T	 O   O
+//                          L		 T		T	 O   O
+//                          L		 T		T	 O   O
+//                          LLLLL    T		T	  OOO
+//==============================================================================
+
+#define BITS          32  // The number of bits in the command
+
+#define HDR_MARK		3000	// The length of the Header:Mark
+#define HDR_SPACE		6000	// The length of the Header:Space
+#define TAG_SYNC		3000	// The lenght of the Sync signal for a Tag:Mark
+#define BEACON_SYNC		6000	// The length of the Sync signal for a Beacon:Mark	
+
+#define ZERO_BIT		1000	// The length of a Bit:Mark for 0's
+#define ONE_BIT			2000	// The length of a Bit:Mark for 1's
+#define BIT_SPACE		2000	// The length of a Bit:Space
+#define LONG_PAUSE		25000	// The length between packets.
+
+//+=============================================================================
+//
+#if SEND_LTTO
+void  IRsend::sendLTTO (unsigned long data,  int nbits, bool beacon)
+{
+	// Set IR carrier frequency
+	enableIROut(38);
+
+	// Header
+	mark (HDR_MARK);		//PreSync
+	space(HDR_SPACE);		//PreSync Pause
+
+	//Sync
+	if (beacon)	mark(BEACON_SYNC);
+	else		mark(TAG_SYNC);
+
+	// Data
+	for (unsigned long  mask = 1UL << (nbits - 1);  mask;  mask >>= 1) {
+		if (data & mask) {
+			space(BIT_SPACE);
+			mark (ONE_BIT);
+		} else {
+			space(BIT_SPACE);
+			mark (ZERO_BIT);
+		}
+	}
+
+	// Footer
+	space(LONG_PAUSE);
+    space(0);  // Always end with the LED off
+}
+#endif
+
+//+=============================================================================
+//
+#if DECODE_LTTO
+bool  IRrecv::decodeLTTO(decode_results *results)
+{
+	unsigned long  data	  = 0;  // Somewhere to build our code
+	int            offset = 0;  // The IF(_GAP) statement sets the Skip the Gap reading
+	int headerSize        = 2;	// Number of bits for the header, altered by IF(_GAP) to 4
+	int tagLength = 16;
+	int beaconLength = 12;
+		results->bits = 0;
+	// Check initial Mark+Space match
+	if (_GAP > 7000)
+	{
+		// The library default for _GAP is 5000, which means the 6000uS Space is seen as a new packet,
+		// therefore the initial 3000uS Mark gets lost, so ignore it unless _GAP > 7000.
+		headerSize	 = 4;		// allow for the 2 extra bits in the packet.
+		tagLength	 = 18;		// allow for the 2 extra bits in the packet.
+		beaconLength = 14;		// allow for the 2 extra bits in the packet.
+		offset++;				// Skip the Gap reading
+		if (!MATCH_MARK(results->rawbuf[offset++], HDR_MARK))  return false;
+	}
+	if (!MATCH_SPACE(results->rawbuf[offset++], HDR_SPACE))  return false ;
+	
+
+	// Check the Sync Type
+	if (MATCH_MARK(results->rawbuf[offset], TAG_SYNC))
+	{
+		if (results->rawlen < tagLength) return false;
+		results->address = 3000;			//TYPE_LAZERTAG_TAG;
+	}
+	else if (MATCH_MARK(results->rawbuf[offset], BEACON_SYNC))
+	{
+		if (results->rawlen < beaconLength) return false;
+		results->address = 6000;			//TYPE_LAZERTAG_BEACON;
+	}
+	else return false;
+	offset++;
+
+	// Read the bits in
+	for (int i = 0; i < ((results->rawlen-headerSize)/2); i++)
+	{
+		// Each bit looks like: SPACE + MARK_1 -> 1
+		//                 or : SPACE + MARK_0 -> 0
+
+		if (!MATCH_SPACE(results->rawbuf[offset++], BIT_SPACE))  return false;
+		
+		// IR data is big-endian, so we shuffle it in from the right:
+		if (MATCH_MARK(results->rawbuf[offset], ONE_BIT))
+		{
+			data = (data << 1) | 1;
+			results->bits++;
+		}
+		else if (MATCH_MARK(results->rawbuf[offset], ZERO_BIT))
+		{
+			data = (data << 1) | 0;
+			results->bits++;
+		}
+		offset++;
+	}
+
+	// Success
+	results->value = data;
+	results->decode_type = LTTO;
+	
+	//Serial.print("\n\nSuccess = LTTO");
+
+	return true;
+}
+#endif