OpenLaserTag IR protocol

Overview

OpenLaserTag protocol is based on the MilesTag II protocol, extends its capabilities and is backward-compatible with this protocol. Allows up to 32767 unique player ID, 15 bits for player ID. It allows Big Game for many players. The last 1024 IDs reserved and indicate anti-materiel weapons. This fully penetrate armored target.

Modulation

The protocol uses pulse width encoding of the bits. The pulse representing a logical “1” is a 1.2ms long burst of the 56kHz carrier, while the burst width for a logical “0” is 0.6ms long. All bursts are separated by a 0.6ms long space interval. The recommended carrier duty-cycle is 1/3. Receiver

OpenLaserTag Packet

The LaserTag uses two types of packets. The Shot packet is used for shooting. The Command packet is used for game moderation and basic player settings. The Advanced player settings are realized with using other wireless technologies or IR protocol extensions.

The Shot Packet begins with a 2400us header followed by a 600us pause. The data partion for the Shot Packet is 22 bits. The first bit specifies Shot Packet. “0” indicates Shot Packet, “1” indicates Command Packet. Next 7 bits is the first part of the user ID, it can be the club ID for backward compatibility. Next 2 bits is team ID. Next 4 bits damage. Last 8 bits is the second part of the user ID. The most significant 3 bits this second part indicate anti-materiel weapons.

The Command Packet begins with a 2400us header followed by a 600us pause. Next 24 bits that contain a command message. Italic indicates expansion beyond MilesTag II.