The Heads Up Display unit, or HUD for short, is a visor mounted display, and is probably the second most useful element in the MJOLNIR Armor, coming just short of their Personal Energy Shields.
The Heads-Up Display is the main source for information in-game on Halo: Combat Evolved and Halo 2. Sensors augmented into the Spartan's body read vital signs, and display a general wellbeing bar, much like a "Health Bar" in classic video-games. Additionally, it can read the shield level, from the energy signatures it emanates, and displays it in a bar unit. It can also, through sensors placed in the Spartan's glove, read a weapon's ammunition and heat levels.
The Motion Sensor is another important HUD element. It can sense and track movement in a 15 metre radius, and can also tell friend from foe, due to the technology that being has or is operating. Waypoint indicators are an on screen directive that are lain down by an AI. They point out important elements or locations in the Spartan's mission, and are extremely useful, measuring the distance the Spartan is from the objective.
A HUD display is featured on SPI Armor, MJOLNIR armor, ODST Body Suits, Marine Body Armor, and even the Elite armor.
Confirmed Readouts
MJOLNIR armor, SPI armor, and Elite armor
The standard MJOLNIR armor contains the following readouts:
- A meter displaying the relative Health of the user
- A gauge displaying Shield status
- A gauge tracking the quantity of ammunition available for weapons carried
- A motion tracker
- A counter tracking the number and type of Grenades carried
- A targeting reticule which changes relative to the weapon currently in use
- Acknowledgment lights from other members of the wearer's team
- Maps and information uploaded over the wearer's TACCOM.
- Zoom Function or function for using a Fiber Optic Probe.
ODST Body Suit and Marine Body Armor
- A gauge tracking the quantity of ammunition available for weapons carried
- A motion tracker
- A counter tracking the number and type of Grenades carried
- A targeting reticule
- Acknowledgment lights from other members of the wearer's team
- Maps and information uploaded over the wearer's TACCOM.
Trivia
- It is unknown how the Elites see their HUD due to the fact that they have no visor or digital readout. Some speculate optical implants.
- Custom games in Halo 3 let you be able to change how far your radar reads (10 metres, 25 metres, 75 metres or 150 metres).