This page covers the device-specific wiring for a beam sensor (sender + receiver pair). For general device setup and activity settings, see Add device.
The beam sensor detects when something crosses a beam between a paired sender and receiver. Useful for monitoring intrusion across a defined line — companionways, gangways, dock access, or any space that should remain clear.
Uses a digital input slot (4–7) on the BRNKL connector.
The BRNKL 5G wiring is different from BRNKL Blue. The BRNKL 5G uses dry contact inputs — the white wire is pulled to ground when the beam breaks. The BRNKL Blue uses wet contact inputs — the white wire goes high. Using the Blue wiring method on the BRNKL 5G will apply DC voltage to a digital input and can damage the unit.
Prerequisites
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Beam sensor sender + receiver pair
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12–24 V DC unswitched power supply
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Marine-grade wiring if extending the supplied leads
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An available BRNKL digital input (slot 4, 5, 6, or 7)
Wiring
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Red wire → common ground
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Black wire → 12–24 V DC supply (unswitched)
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White wire → BRNKL connector digital input slot 4, 5, 6, or 7
When the beam breaks, the internal relay closes and pulls the white wire to ground, triggering the input.
Note which slot you use — you will need it when configuring.
If you need to extend the wiring, splice in marine-grade 18 AWG (or larger) wire. Ensure all splices are sealed and rated for the marine environment.
Mount sender and receiver
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Align the sender and receiver so they face each other directly with a clear line of sight.
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Maximum separation: 30 ft (≈ 9 m).
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Secure each unit to prevent misalignment from vibration or movement.
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During installation, monitor the LED on the sensor enclosure:
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LED not blinking — beam is intact and aligned.
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LED blinking — beam is broken (trigger condition).
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Configure
In the BRNKL app, go to Settings > Devices and select the input matching your slot:
|
Slot |
App setting |
|---|---|
|
4 |
Digital 1 |
|
5 |
Digital 2 |
|
6 |
Digital 3 |
|
7 |
Digital 4 |
This is a Digital input. Recommended settings:
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Monitor — on
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Alert — on
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Name — e.g., Beam sensor or Gangway
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High Name — Clear
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Low Name — Triggered
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Alert On — Low (alerts when beam is broken)
Tap Save.
Test
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Wait 15 minutes for settings to sync.
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With the beam unobstructed, confirm the LED is not blinking and the input shows Clear.
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Pass an object or person through the beam path. The LED should blink and the BRNKL input channel should switch to Triggered.
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If LED behaviour is inconsistent, fine-tune the alignment between sender and receiver.
Troubleshooting
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LED stays blinking constantly — check alignment and ensure no obstructions or reflective surfaces are interfering with the beam path.
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LED never blinks when obstructed — verify wiring (power, ground, and the white wire to the correct slot) and confirm the correct Digital input is enabled in the app.