Specna Arms HAL™ ETU Electronic Trigger Unit for V2 Gearboxes

Specna Arms HAL™ ETU Electronic Trigger Unit for V2 Gearboxes

The Specna Arms HAL™ ETU is a programmable electronic trigger unit designed for compatible Version 2 AEG gearboxes, particularly M4/AR15-style airsoft rifles. Using magnetic Hall-effect trigger detection and an optical gear sensor, the system provides precise trigger control, adjustable pre-cocking, programmable firing modes and electronic protection functions. It is a practical upgrade for players looking to improve trigger response, customise firing behaviour and replace conventional mechanical trigger contacts with an advanced electronic system.

The HAL™ ETU offers extensive customisation without requiring a separate programming device or computer. Settings are adjusted directly through the trigger and fire selector, making it possible to fine-tune the replica's operation for different playing styles and preferences. The package includes a dedicated trigger, V2 selector plate, installation components and a programming reference card.

Magnetic Trigger Detection and Improved Responsiveness

Instead of conventional mechanical trigger contacts, the HAL™ system uses magnetic sensors based on the Hall effect to detect trigger movement. This contactless detection reduces wear associated with mechanical contacts and allows the trigger activation point to be adjusted electronically.

Trigger sensitivity can be configured in five levels, from 20% to 100% of the trigger travel. A shorter activation distance provides a more responsive trigger feel, while a longer distance offers a more deliberate activation point.

The system also uses an optical gear detection sensor to monitor gearbox operation. Together, these technologies provide the foundation for the HAL™ system's programmable firing functions and electronic cycle control.

Six-Level Pre-Cocking for Faster Trigger Response

The HAL™ ETU features adjustable pre-cocking with six levels. This function controls the position in which the piston stops after a firing cycle, allowing it to remain partially or almost fully tensioned for the next shot.

With pre-cocking enabled, the gearbox does not need to complete the entire piston compression cycle after each trigger pull. This can noticeably reduce the delay between pulling the trigger and firing, making semi-automatic operation feel faster and more responsive.

The six adjustment levels range from the fully released piston position to a rearward pre-tensioned position. Higher pre-cocking settings place additional load on the spring and gearbox components, so the appropriate setting should be selected according to the build.

Programmable SEMI and AUTO Firing Modes

The HAL™ ETU allows the firing behaviour assigned to the SEMI and AUTO selector positions to be customised independently. This gives players considerably more flexibility than a conventional mechanical trigger system.

Available AUTO selector modes:

• Full Auto - Continuous automatic fire while the trigger is held
• Semi-Auto - One shot per trigger pull
• 3-Round Burst - Three shots per trigger pull
• 5-Round Burst - Five shots per trigger pull

Available SEMI selector modes:

• Semi-Auto - One shot per trigger pull
• Binary Trigger - One shot when pulling the trigger and another when releasing it
• AUG Mode - Partial trigger pull for semi-automatic fire and full trigger pull for automatic fire
• Sniper Mode - Semi-automatic fire with a two-second delay between shots and an audible indication when the next shot is available

These options allow the replica to be configured for different playing preferences, from conventional semi-automatic operation to controlled burst fire or a particularly responsive binary trigger. The Sniper mode also provides a built-in firing delay for setups where a slower rate of fire is desired.

AUG mode requires the trigger adjustment screw to be in its neutral position, as specified in the manufacturer's manual.

Active Brake and Electronic Protection

The adjustable active brake function stops the motor after the firing cycle, helping prevent unwanted gearbox overspin. This is particularly useful in configurations where the motor and gear combination would otherwise continue rotating after the trigger is released.

The HAL™ system also includes several protection functions that monitor electrical and mechanical operation. If an abnormal condition is detected, the system can interrupt operation to help prevent further damage.

• Active brake with ON/OFF adjustment
• Low-voltage protection and battery warning
• Overvoltage protection
• Overload protection if the firing rate exceeds 40 rounds per second
• Protection against abnormal gearbox operation
• Alarm indication through three consecutive motor vibrations
• Compatibility with brushless motors

The HAL™ ETU supports brushless motors, making it suitable for more advanced AEG electrical configurations. When using a brushless motor, the active brake must be disabled according to the manufacturer's instructions.

Specna Arms recommends an 11.1V LiPo battery for optimal performance. The battery should be disconnected whenever the replica is not in use, as the ETU continues to consume a small amount of power in standby mode.

Programming Without an External Device

All HAL™ settings can be programmed using the replica's trigger and fire selector. The programming menu allows the user to select firing modes, adjust trigger sensitivity, configure pre-cocking and enable or disable the active brake.

The included programming reference card provides a convenient guide for changing settings, while the complete manufacturer manual explains the programming procedures and available functions in detail.

Trigger Activation Before First Use

The HAL™ trigger must be activated before the first use and after restoring factory settings. The procedure is performed after installation using the following steps:

• 1. Set the replica's fire selector to SAFE.
• 2. Connect the battery while the selector remains in SAFE.
• 3. Wait approximately 3 seconds until the replica emits a beep.
• 4. Pull the trigger fully and hold it for approximately 5 seconds.
• 5. A second beep confirms successful trigger activation.

After activation, the HAL™ ETU is ready for normal operation and programming.

Compatibility and Installation

The Specna Arms HAL™ ETU is designed for compatible Version 2 gearboxes commonly found in M4/AR15-style AEG replicas. Compatibility with individual gearbox shells and receiver configurations may vary.

The dedicated trigger included in the package must be installed for the HAL™ system to operate correctly. Installation requires familiarity with AEG gearbox construction and careful positioning of the electronic components and sensors. Specna Arms recommends installation by a qualified airsoft technician.

Special care must be taken to keep the optical sensor clean, maintain the required clearances around the gears and ensure the electronic unit is correctly secured. Incorrect installation or battery connection may permanently damage the electronics.

Technical Specifications

• Manufacturer: Specna Arms
• Model: HAL™ ETU
• Product type: Programmable electronic trigger unit
• Gearbox compatibility: V2
• Primary platform: M4 / AR15 AEG
• Trigger detection: Magnetic Hall-effect sensors
• Gear detection: Optical sensor
• Trigger sensitivity: 5 levels (20%, 40%, 60%, 80%, 100%)
• Pre-cocking: 6 adjustable levels
• Active brake: ON / OFF
• AUTO firing modes: Full Auto, Semi-Auto, 3-Round Burst, 5-Round Burst
• SEMI firing modes: Semi-Auto, Binary, AUG, Sniper
• Programming: Trigger and fire selector
• Operating voltage: 5.0-15.5V
• Recommended battery: 11.1V LiPo
• Motor compatibility: Brushed and brushless motors
• Protection functions: Low voltage, high voltage, overload and abnormal operation
• Manufacturer product code: SPE-08-048398
• EAN: 5902543215192

Package Contents

• 1 × Specna Arms HAL™ ETU electronic trigger unit for V2 gearboxes
• 1 × Dedicated trigger
• 1 × Installation kit
• 1 × V2 selector plate
• 1 × Rigid plastic programming reference card

HAL™ ETU User Manual

For detailed instructions on programming firing modes, adjusting trigger sensitivity and pre-cocking, restoring factory settings, interpreting protection alarms and installing the system correctly, refer to the official Specna Arms manual.

Specna Arms HAL™ ETU User Manual (English / Polish, PDF)