TR/9 trip mine

The TR/9 Antipersonnel Mine, commonly known as the trip mine, is a landmine used by the United Nations Space Command.

Overview
The Trip Mine is deployed as an anti-infantry or anti-vehicle weapon. It is sensitive to either proximity, pressure or both, and can be detonated by weapons fire or the close proximity or impact of a vehicle or infantryman. It is apparently capable of detecting the anti-gravity generators found on Covenant vehicles. The mine will explode after ninety seconds if not detonated before then. It will not detonate, however, if a player crouch-walks over it. The technology it uses to detect nearby objects may be similar in nature to that of the Motion tracker, which also fails to detect stationary vehicles and slow, crouched players.

Once deployed, it can be identified by a high-pitched beeping noise, four inner spokes that rise up, and a distinctive flashing bright orange light on its top. Its blast radius is considerably larger than a grenade or rocket explosion, throwing vehicles and personnel into the air. Despite this blast radius, however, Trip Mines can only slightly injure Spartans and Elites positioned near the edge of the blast radius, and it takes two direct hits with a Trip Mine to kill a Spartan or Elite. It will, however, kill Brutes, Grunts, Jackals, and unwary Marines, even if they are on the edge of the blast. The greater damage to Brutes may be due to the fact that their armor has no shielding and is weaker than the Mark VI and Elite shielding.

The Trip Mine spawns by default on Sandtrap, Rat's Nest, and Avalanche. Jump Pack Brutes have been seen deploying the mines against nearby players in Tsavo Highway. Destroying a vehicle with the Trip Mine in Campaign or Matchmaking will unlock the We're In For Some Chop achievement.

Disadvantages

 * Sometimes, while playing in Multiplayer or Campaign, players can either accidentally run or drive over their own Trip Mines or those of their teammate(s).
 * A Trip Mine's distinctive beeping and orange glow makes it easy to detect.
 * The Trip Mine will only stay active for 90 seconds before spontaneously exploding.
 * Trip Mines can be detonated from a distance by weapons fire, and are therefore only useful when unnoticed.
 * The Trip Mine is often difficult to use in split-screen local games due to the sound it makes when deployed, causing other players to screenwatch.

Trivia

 * Even though it's said that this is UNSC equipment, Jump Pack Brutes always have one ready to use and no Marine or ODST has been seen holding one, though there are several Mines in a Marine base on Tsavo Highway.
 * The Trip Mine's heads-up display icon, along with that of the Bubble Shield, can be used in a Halo 3 Emblem.
 * Trip mines can be used to overload a map or launch an Elephant.
 * During the initial unveiling of Halo 3, a Bungie employee claimed that, "The Trip Mine is probably going to be used as a 'I got you' weapon as people only seem to drop it right before being splattered."
 * In the Halo 3 Beta, deployed Trip Mines could stick to the bottom of a motionless vehicle. If the vehicle then moved, the Trip Mine would explode, killing all players inside of it
 * The shape of the Trip Mine resembles the German made Tellermine series of anti-tank mines developed and used during the Second World War; both mines are hand carried to their targets and are sometimes tossed into the way of an enemy tank in hopes of destroying it.
 * If a trip mine is dropped from a high location while active it will explode on impact.
 * A trip mine will not detonate if walked over while crouching.

List of appearances

 * Halo 3
 * Halo: Spartan Assault
 * Halo Online