Tripwire and line crossing detection for gates and driveways

The question is simple: did someone come through?

At a gate or an entrance, the question is rarely "is anything moving?" It is "did a person walk through here?" or "did a vehicle just drive in?"

A virtual tripwire answers that question directly. It is not a physical wire and there is nothing to see in real life. It is a line drawn across the camera image, and the system watches for anything crossing it.

How it works, in plain words

During setup, we draw a line across the part of the picture you care about. On compatible Dahua systems, the camera or recorder then detects when a person or a vehicle crosses that line and flags the event.

You can use it across:

• an entrance or doorway
• a driveway
• a gate
• the edge of a restricted area

Because it is about crossing, not presence, it suits places where people often stand near a point but only passing through matters.

What the rule can include varies with the equipment, and we confirm the options during planning.

Tripwire or intrusion zone?

They are close relatives, and the choice is a matter of shape.

• A zone (see intrusion detection) covers an area and reacts to a person inside it.
• A tripwire covers a line and reacts to a crossing.

If you have a wide yard you want to watch, use a zone. If you have a narrow entry you want to log, use a tripwire. Some properties use both, and we are happy to recommend the right mix.

Placement advice

The line is only as useful as where we put it. A few things we think about.

• Across the natural path. Place it where people and vehicles must pass, not where they could simply walk around it.
• Set back from the boundary. A line right on the fence can be triggered by passers-by on the street. A line a little inside gives clearer, more meaningful alerts.
• At a good angle. Crossing across the camera's view is usually easier to detect than directly toward or away from the lens.
• Away from clutter. Overhanging branches and swinging gates near the line cause confusion.

What you get day to day

When a person or vehicle crosses the line during the schedule you set, you receive a notification through DMSS. You tap it, watch the clip and see the camera view. If you want to check something later, the recorded footage is on your recorder, and intelligent video search can help find events on compatible systems. Our DMSS mobile app page explains what you can do from your phone.

Where it suits best

• Driveways and garages and backyards and gates.
• Warehouses and yards with a controlled entry.
• Construction sites with a defined gate.
• Entrances to commercial properties where a record of arrivals is useful.

What to know

Compatible systems only. Tripwire is available on compatible systems, depending on the selected camera and recorder. AI features vary, and entry-level equipment may offer basic motion detection only. Your quote spells out what is included.

A line can be crossed in ways you did not plan. Someone could climb a fence away from the line or enter by a path we did not cover. A tripwire watches the line, not the whole property.

Crowded crossings are harder. Several people crossing close together are harder for any camera to separate than one person on their own.

It detects, you decide. An alert tells you something crossed. It does not know who they are or why they came.

No guarantee. We do not claim it will catch every crossing or prevent any incident.

Privacy. Keep the camera view and line focused on your own property. Surveillance and workplace-surveillance rules differ across states and territories. This is general information, not legal advice, so check your own state's rules.

Next steps

For setup guidance in plain English, you can read our how it works page. When you want a line drawn on your own gate, call 1300 263 551 or get in touch.

Frequently asked questions