ASP1-NS Infra-Red Model Railway Signal Controller - 2, 3 & 4 Aspect

About the Product

The BLOCKsignalling ASP1-NS is a compact infra-red model railway signal controller for 2-, 3- and 4-aspect common-cathode LED signals. Its built-in infra-red train sensor automatically detects passing trains and changes the connected signal through realistic signalling sequences, with no separate detector or track isolation required.

The sensor projects invisible infra-red light upwards and detects reflections from the underside of passing rolling stock. Installation is straightforward: drill an 8mm hole between the sleepers and insert the sensor from beneath the baseboard. Only a small gap is required between the sleepers, making the module suitable for N gauge as well as larger scales.

During normal operation, the signal displays green. When a train passes over the sensor, the ASP1-NS automatically changes the signal to red. Once the complete train has cleared the detector, the signal progresses back towards green, passing through yellow and double yellow where appropriate for the selected signal type.

The ASP1-NS also provides realistic fading between signal aspects to simulate traditional filament lamps. Although the module operates automatically using its default settings, signal timings, detection release time, fade rates and LED brightness can all be adjusted if required.

Key Features

• Automatic model railway signal control using infra-red train detection.
• Built-in infra-red sensor for simple installation.
• Supports 2-, 3- and 4-aspect LED signals.
• Designed specifically for common-cathode (common-negative) signals.
• Automatically changes the signal to red when a train is detected.
• Automatically returns through the appropriate aspects to green after the train has passed.
• Realistic fading between signal aspects to simulate filament lamps.
• Adjustable red, yellow and double-yellow timings.
• Adjustable detection release time to accommodate gaps between rolling stock.
• Adjustable LED brightness and aspect fade rates.
• No soldering required.
• No programming required for normal operation.
• Built-in LED resistors mean external resistors are normally not required.
• Suitable for N gauge and larger model railway scales.
• Requires a 12V DC power supply.
  

2-, 3- and 4-Aspect Signal Operation

The ASP1-NS can operate 2-, 3- or 4-aspect signals. It is supplied programmed for 4-aspect operation and can be reprogrammed for signals with fewer aspects.

In 2-aspect mode, the signal normally displays green. When a train is detected, it immediately changes to red and remains red while the sensor is occupied. After the train has cleared and the programmed release and red times have expired, the signal returns to green.

In 3-aspect mode, the signal changes from green to red when a train is detected and subsequently progresses through yellow and back to green after the train has cleared.

In 4-aspect mode, the signal changes immediately to red when a train is detected. After the train has cleared, it progresses through yellow, double yellow and then green according to the programmed timings.

Built-In Infra-Red Train Detection

Unlike signal controllers that use a separate detector, the ASP1-NS has its infra-red sensor built directly into the module. The controller is mounted beneath the track with the sensor positioned through an 8mm hole in the baseboard between the sleepers.

Invisible infra-red light is projected upwards, and passing trains trigger the controller automatically. The sensor requires only around a 2mm gap between the sleepers, allowing it to be installed on N gauge layouts as well as larger scales.

Signal Compatibility

The ASP1-NS is specifically designed for common-cathode (common-negative) LED signals and is not suitable for bulb-based signals.

The module provides the connections for red, yellow, green and second-yellow aspects. LED resistors are built into the controller, so external resistors are normally unnecessary.

Common-anode signals are not compatible with the ASP1-NS.

Electrical Requirements

• Supply voltage: 12V DC
• Current consumption: Less than 10mA (0.01A)
• Recommended power supply: 0.5A to 1A
• Signal type: Common-cathode (common-negative) LED
• Signal aspects: 2, 3 or 4
• Detection method: Built-in reflective infra-red sensor
• Baseboard mounting hole: 8mm
• External LED resistors: Normally not required

Many ASP1-NS modules can be powered from a single suitable 0.5A to 1A 12V DC supply due to the low current consumption of each controller.

Do not power the ASP1-NS from the auxiliary terminals of a train controller. The manual warns that these outputs may not provide sufficiently smooth or stable power and could cause unpredictable operation or damage. Reversing the polarity of a DC supply will not damage the module, but it will not operate until the polarity is corrected.

Documentation & Support

For installation instructions, wiring guidance, operating details, programming information, and troubleshooting assistance, please download the latest instruction manual:

Product Instruction Manual