Infrared Guns — LED Boards, Sensor Units and Cameras, 2002 to 2014

Sega's gun-sense system from The House of the Dead III to The House of the Dead 4, Namco's Time Crisis 4 mask of twenty filters, and Raw Thrills' camera rifles: what moved off the CRT, what the operator has to clean, and why two cabinets side by side need different frequencies

By the early 2000s the arcade’s biggest gun games were on projection screens. A rear-projection set is still a CRT inside, but its picture is three tubes’ light through a lens and a screen, dimmer and less sharply timed than a direct-view tube. The makers’ answer, visible in their manuals from 2002, was to stop asking the gun to see the picture at all. Infrared emitters went into the mask around the screen, a sensor went into the gun, and the display became a display again.

The tracking theory (how a sensor in the gun turns a few bright points into an aim) is the planned IR Point Tracking dive’s. The makers did not publish it; this volume records what their manuals do show.

4.1 Why the Arcade Moved to Infrared

The manuals give the displays:

Table 1 — The manuals give the displays

Cabinet	Year	Display, as the manual gives it	Gun sensing
The House of the Dead III DX	2002	PTV (projection television)	Infrared¹
Ghost Squad (Deluxe)	2004	PTV, with convergence adjustment	Infrared²
The House of the Dead 4	2005	Projector	Infrared³
Time Crisis 4 DX	2006	”Thomson 46” Projection – 46KH412S”	Infrared⁴
Terminator Salvation (Deluxe)	2010	42-inch monitor	Camera and IR⁵
Aliens Armageddon (Deluxe)	2014	55-inch LCD	Camera and IR⁶

Every early infrared cabinet in the table still had a CRT projector, with convergence to adjust. The move to infrared came before the move to flat panels, and made it possible: once the gun no longer timed the picture, nothing stopped the next cabinet using an LCD.

4.2 Sega’s Gun-Sense System: The House of the Dead III, 2002

Figure 1 — The SPX-0530UK mask assembly from Sega's The House of the Dead III DX service manual: the mask base that frames the projection screen, with fittings for the IR covers (2) and LED boards (101) aroun… — Figure 1 — The SPX-0530UK mask assembly from Sega's The House of the Dead III DX service manual: the mask base that frames the projection screen, with fittings for the IR covers (2) and LED boards (101) around the opening; the list gives ten of each. The parts list names the boards "LED BD GUN SENSE HOD" (838-13145-02) and wires them with seven short and two long mask harnesses. Drawing from the Sega Amusements Europe House of the Dead III DX service manual, 420-6742-01UK, 2002, page 85, via the Internet Archive.

The UK service manual for The House of the Dead III DX (© Sega 2002) is the earliest manual found for this dive that describes the system Sega used for the next decade. It has two halves:

Table 2 — The UK service manual for The House of the Dead III DX (© Sega 2002) is the earliest manual found for this dive that describes the system Sega used for the next decade. It has two halves

Where	Part	Number	Quantity
Mask round the screen	Mask base	HOD-1151	1
	IR cover	JPT-1082	10
	LED BD GUN SENSE HOD	838-13145-02	10
	Wire harness mask short / long / into	SPY-60024 / -60025 / -60026	7 / 2 / 1
In the gun	Sensor unit	JPT-2030	1 per gun
	— sensor holder	JPT-2031
	— SENSOR BD GUN SENSE	838-13144

Source: §8.4 Assy Mask and §8.13 Sensor Unit.¹

Figure 2 — The JPT-2030 sensor unit: a cylindrical holder (1) with a window at the front end, and the 838-13144 sensor board (101) mounted on its back with a row of header pins. It fits in the gun's barrel. D… — Figure 2 — The JPT-2030 sensor unit: a cylindrical holder (1) with a window at the front end, and the 838-13144 sensor board (101) mounted on its back with a row of header pins. It fits in the gun's barrel. Drawing from the Sega House of the Dead III DX service manual, 2002, page 96, via the Internet Archive.

The gun itself, control unit HDT-2100, is a pump shotgun: an “ASSY SLIDE MECHA” (HDT-2120), slide grips, a front sight, a trigger on a microswitch (SS-5GL2, 509-5080) and the JPT-2030 sensor unit.¹ The input test shows what the game receives from it:

“GUN-X: The X-direction (horizontal) sight position for the guns. GUN-Y: The Y-direction (vertical) sight position for the guns. SCREEN-IN: Detection of the gun sight sensors … Input is normal if the display to the right of SCREEN-IN changes from OUT to IN when the shotgun is pointed at the screen.”¹

The manual calls the whole arrangement “the same or similar infrared sensing system” and “the gun sense system”.¹ It does not say whether the sensor board is an image sensor or a set of photodiodes; the parts list names only a board.

4.3 Ghost Squad and The House of the Dead 4, 2004 and 2005

Sega kept the parts. The Ghost Squad deluxe manual (first printing November 2004) lists an “IR COVER” (JPT-1082) and “LED BD GUN SENSOR HOD” (838-13145-02) on its mask assembly and the same JPT-2030 sensor unit with its 838-13144 “SENSOR BD GUN SENSE” in the gun.² Its troubleshooting table gives the failure modes of the system:²

Table 3 — Ghost Squad and The House of the Dead 4, 2004 and 2005

Cause given	Countermeasure
”Sights are not aligned due to changes in the surrounding environment”	Sighting adjustment in test mode
”LED board malfunctioning"	"Check to ensure that the LED lights up. If it does not light up, replace"
"Sensor unit malfunctioning”	Replace the sensor unit
”LED board and LED board cover are contaminated”	Wipe off soiled surfaces

The LED board replacement page puts the test in one line: “In case two of LED’s do not emit light, failure and malfunctioning may be considered.”² Each board carries two LEDs.

The House of the Dead 4 (2005) uses the same sensor unit (JPT-2030, listed with an 838-13144R sensor board) in a control unit numbered HDF-2100, and the same “LED BD GUN SENSE HOD” on the mask.³ Its output test lists “GUN MOTOR1” and “GUN MOTOR2” — the gun has a motor (Volume 5).³

Figure 3 — Two players at The House of the Dead 4 cabinet, guns in hand, in front of the projection screen. Photo: Anonimohombre, Wikimedia Commons, CC BY-SA 4.0.

That three games across four years share one sensor-unit number and one LED-board number, and that the board’s name carries “HOD”, says that Sega designed the system once, around The House of the Dead, and reused it.

4.4 Namco Time Crisis 4, 2006

Namco’s Time Crisis 4 DX manual describes a system of the same shape with different parts. The mask around the 46-inch projection screen holds LED boards behind filters, and the gun holds a “Light Receiving Unit” (XTC4-306-754).⁴

Figure 4 — Time Crisis 4 DX, replacing the LED board: the monitor mask seen from the rear with its LED boards around the opening, each board carrying two LEDs (the red spots), an IN and an OUT connector to ch… — Figure 4 — Time Crisis 4 DX, replacing the LED board: the monitor mask seen from the rear with its LED boards around the opening, each board carrying two LEDs (the red spots), an IN and an OUT connector to chain it to the next, and a filter on the front. The note at the foot reads "Ensure that the LED Board is the correct way round." Drawing from the Namco Time Crisis 4 DX manual, issue 2, page 76, via the Internet Archive.

The operator is told to “Clean the following sensor section’s filters (20 locations) on the Monitor Mask everyday to maintain gun accuracy”, that “Scratches on the monitor mask can affect the Gun Assy detection performance”, and that “If the two LEDs (red spots) under the Monitor Mask’s filter … do not illuminate, the LED board may be defective” — and “any defective LED Board will prevent the proper functioning of the game”.⁴ The boards are static-sensitive, chained by IN and OUT connectors, and the manual’s instruction for a defective one is to replace it “as soon as possible”.⁴

The gun-initialise screen spells out the system’s limits. When the gun is aimed off the screen the game shows “OUT OF SCREEN”; if that message appears when the gun is on the screen, the causes are:⁴

“Bright light shining or reflecting on the LEDs around the screen.”
“Gun Assy too close to the screen. (less than 60cm)”
“The gun is at too great an angle to the screen.”

The 60 cm minimum is the only distance limit found in any arcade manual for this dive, and it fits a sensor in the gun with a limited field of view: too close, and the LEDs on the far side of the mask fall outside it.

Figure 5 — The Time Crisis 4 Gun Assy: gun bodies (1, 2), slides (3, 4), the rectangular solenoid unit (16) on its bracket (6) with the spring and rubber spacer (10), the trigger microswitch (17), and the lig… — Figure 5 — The Time Crisis 4 Gun Assy: gun bodies (1, 2), slides (3, 4), the rectangular solenoid unit (16) on its bracket (6) with the spring and rubber spacer (10), the trigger microswitch (17), and the light receiving unit (19) in the upper receiver; the harness (14) leaves through the tube bracket (8). Drawing from the Namco Time Crisis 4 DX manual, issue 2, page 120, via the Internet Archive.

The parts list gives Gun Assy (Red) XTC4-717-333 and Gun Assy (Blue) XTC4-717-355, Solenoid Unit XTC4-717-316, Microswitch XTC4-000-666 and Light Receiving Unit XTC4-306-754.⁴ The recoil is in Solenoid Recoil.

A forum claim worth recording as unverified: an Arcade-Projects member wrote in 2019 that “Cobra the Arcade and Time Crisis 4 use IR guns that are cross-compatible with the Sega IR system”.⁷ Nothing in the Namco or Sega manuals read here confirms or refutes it; the part numbers are different.

4.5 Two Cabinets Side by Side: the Frequency Jumper

Both makers expected the same problem and solved it the same way. Sega, The House of the Dead III:¹

“When games with the same or similar infrared sensing system are installed side by side, interference may occur causing malfunction or inaccuracy of the sensing system in adjacent games. A removable wire harness controls the operating frequency of the gun sense system. Removal of this harness switches from the default frequency to an alternate one. Where game machines of the same or similar type are installed side by side, remove the jumper harness (SPY-60010UK) from every other machine in the line.”

Namco, Time Crisis 4:⁴

“If machines using the same gun detecting system are installed side by side, cross talk may occur between them resulting in machine malfunction. If machines of the same type are to be installed side by side, make sure that they are alternately ‘Frequency Change connector’ installed Game PCB and ‘Frequency Change connector’ not installed Game PCB models.”

“Operating frequency” implies that the LEDs are modulated and the gun’s receiver is tuned to the modulation, so that a neighbour’s LEDs, at the other frequency, are rejected. Neither manual gives the frequencies. For a home builder the lesson is direct: an unmodulated IR marker bar is open to exactly this interference from a second gun system in the same room, which IR Point Tracking takes up.

4.6 Raw Thrills: a Camera in the Rifle, 2010 and 2014

Figure 6 — Terminator Salvation in an arcade, 2010s: the deluxe cabinet's large screen at left and a player with the tethered rifle at the pedestal. Photo: FR, Wikimedia Commons, CC BY-SA 4.0.

IR Gun Calibration, with a dot showing “the spot where the gun is aimed”.
Gun Camera Test. “Each gun controls a dual-track of colored dots. As you tilt each gun, the orientation of the tracks rotates as the sensors perceive the change in angle. The strength of each gun’s signal is noted in a bar chart … Note whether any of the dots disappear or flicker when near the center of the screen. This may indicate a dirty or poorly functioning camera inside the gun.”
Gun Sensor Test. “POINT EITHER GUN AT THE SCREEN AND AIM ALL AROUND TO ACTIVATE ALL THE SENSORS. ACTIVE SENSORS ARE GREEN. INACTIVE ARE RED … If any squares remain red as the gun passes them, that particular IR sensor may be dirty or damaged.”

The first test shows the camera reporting rotation as well as position: it sees more than one point and knows their orientation. The manual calls the screen-side units “IR sensors” and warns that “Locating the cabinet near neon lights may reduce the ability of the IR sensors to accurately track the guns.”⁵ With a camera in the gun, the screen-side units must be what the camera sees; that they are emitters is the obvious reading, but the manual does not use the word.

Aliens Armageddon (© 2014) gives part numbers. Its deluxe rifle contains a “Camera Assembly (Complete)”, 820-00010-01, on a “Hose and Harness Assembly USB 12 Cond”, 96-1047-20, with an “LED PCB F/T4 Rifle” (500-00083-01) and a solenoid recoil (Volume 5).⁶ The routine maintenance, done “every time you empty the cash box”, starts “Check the camera lens. Observe the tinted lens to ensure it has no cracks, scratches or dirt”, and ends “Check IR sensors (Deluxe model only). The IR sensors are directly below and above the printed marquee on the monitor assembly.”⁶ The instruction “Recalibrate the guns any time the game is moved or the guns are repaired, replaced or swapped” closes the list.⁶

Figure 7 — The Aliens Armageddon deluxe rifle from the service manual: rifle halves (1, 2), the camera assembly (14) behind the barrel cap (5), the USB hose and harness (13), and the recoil parts in the recei… — Figure 7 — The Aliens Armageddon deluxe rifle from the service manual: rifle halves (1, 2), the camera assembly (14) behind the barrel cap (5), the USB hose and harness (13), and the recoil parts in the receiver, solenoid (35) in its housing bracket (34), brass knocker (33), recoil rod (17) and spring (22). Drawing from the Play Mechanix / Raw Thrills Aliens Armageddon service manual, 2014, page 56, via the Internet Archive.

A USB camera in the gun and infrared units at the screen is the architecture of the home guns this category is building: a PixArt-type tracking camera and an LED bar (Reference Electronics, Open-Source Firmware). The Raw Thrills manuals do not name the camera’s maker.

4.7 Optical, Positional and Infrared Compared

Table 4 — Optical, Positional and Infrared Compared

	Optical (Volume 2)	Positional (Volume 3)	Infrared (this volume)
Needs from the display	A CRT’s scanning beam, bright	Nothing	Nothing (the mask carries the emitters)
Gun	Handheld or mounted	Mounted only	Handheld or mounted
Daily cleaning	Gun lens	None	Gun lens and screen-side filters
Upset by	Room light, reflections, dim tube, purity	Worn pots and gears, lost calibration	Bright light on the LEDs, a neighbour on the same frequency, too close or too steep
Calibration	Per gun, often	Three points, stored	Per gun, after any move
Works on an LCD today	No (Volume 6)	Yes	Yes

4.8 What could not be verified

The LED wavelength and modulation frequency of the Sega and Namco systems; neither manual gives them.
What the Sega 838-13144 and Namco XTC4-306-754 sensors are (image sensor or photodiodes).
Cross-compatibility of Time Crisis 4 guns with Sega’s system (one forum post).
Whether Raw Thrills’ screen-side “IR sensors” are emitters; inferred from the camera in the gun.
Ghost Squad and House of the Dead 4 mask board counts; only House of the Dead III’s (ten) and Time Crisis 4’s (twenty filters) were read.

Sources

Sega Amusements Europe, The House of the Dead III DX Service Manual, 420-6742-01UK, © Sega 2002, game board frequency jumper, input test, §8.4, §8.12, §8.13. Internet Archive item manualzz-id-978359. Read 2026-10-19. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶
Sega Amusements USA, Ghost Squad Deluxe Owner’s Manual, Manual No. 4201-6831-01, first printing November 2004, troubleshooting, Replacing the LED BD, Assy Mask, Sensor Unit. Internet Archive item sega-ghost-squad; Library copy. Read 2026-10-19. ↩ ↩² ↩³ ↩⁴
Sega, The House of the Dead 4 Owner’s Manual (2005), output test, Control Unit (HDF-2100), Sensor Unit (JPT-2030). Internet Archive item ArcadeGameManualHod4-manual. Read 2026-10-19. ↩ ↩² ↩³
Namco Bandai Games, Time Crisis 4 DX Operators Manual, Issue 2, Part No. 90500167: specifications, Preventing Cross Talk, Gun Initialize, §7-1-1, §7-1-2, §7-4, §10-14. Internet Archive item time_crisis_4_dx_manual_issue2_ptm; Library copy. Read 2026-10-19. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷
Play Mechanix / Raw Thrills, Terminator Salvation 42” Deluxe Setup and Operations Manual, revision 7.30.12, © 2010, installation cautions and system tests. Internet Archive item manualzilla-id-6035891. Read 2026-10-19. ↩ ↩² ↩³
Play Mechanix / Raw Thrills, Aliens Armageddon Setup and Operation Service Manual, © 2014, maintenance procedure, Deluxe Gun Parts List (pp. 55–56). Internet Archive item manualzilla-id-6032150. Read 2026-10-19. ↩ ↩² ↩³ ↩⁴
“Setup Time Crisis 3”, Arcade-Projects forum, post by twistedsymphony, 11 October 2019, https://www.arcade-projects.com/threads/setup-time-crisis-3.10742/, read 2026-10-19. ↩