Perimeter Security Guides

Do MEMS fence sensors false-alarm in wind and rain?

Wind and rain are the dominant nuisance source in MEMS fence sensing, and a slack fence is the hardest case. What causes it, what classification can do about it, and what it cannot.

MEMS, fibre optic, taut wire or video analytics: how to choose

A side-by-side comparison of the four main perimeter detection technologies, including where each one is the wrong choice and which two we do not sell.

Perimeter intrusion detection systems made in India

What “made in India” should mean for a perimeter system, how to verify it, and what Gandeevan designs and builds in Bengaluru — including what we do not offer.

The technologies at a glance

Perimeter intrusion detection technologies compared, including where each one is the wrong choice.
	MEMS fence sensor	Fibre optic sensing	Taut wire	Video analytics
Detection principle	An accelerometer mounted on the fence senses vibration travelling through the fabric.	The sensing fibre is itself the detector — disturbance alters the light returning along it.	Tensioned wires on dedicated posts; sensors detect displacement or a change in tension.	Cameras plus software that classifies objects and movement within the scene.
What it detects	Climbing, cutting, drilling and impact on the fence or wall it is fixed to.	Disturbance of the cable and of the fence it is attached to. Distributed acoustic sensing additionally resolves the acoustic signature.	Cutting, spreading or climbing — anything that moves the wires.	Approach and loitering before the boundary is touched, and what the intruder is.
Typical false-alarm triggers	Wind, especially on a poorly tensioned fence; heavy rain; nearby vehicle traffic; animals on or along the line.	Wind and rain on the cable; ground-borne vibration; movement of the cable itself where it is loosely secured.	Few from weather, which is the main reason it is still specified. Thermal expansion and ground settlement show up as drift rather than alarms.	Changing light, headlights, shadows, rain or fog on the lens, moving foliage, and insects drawn to infrared illuminators at night.
Supported surfaces	Fencing, brick and masonry walls. Not rock walls.	Anywhere the cable can be run or buried — fence, wall or trench.	Its own posts. It is the barrier as well as the sensor.	Not surface-dependent, but needs sightlines and adequate illumination.
Power and cabling along the line	Powered nodes and a bus cable running the length of the perimeter.	No power and no electronics on the line; all active equipment sits at the interrogator.	Power to each sensor post.	Power and network to every camera.
Locating an event	To the individual node, where each node is separately addressed.	Intensity-based sensing: to a sensing loop. Distributed acoustic sensing: to a position along the cable.	To the zone between two sensor posts.	To the camera's field of view, with an image of what caused it.
Where it is the wrong choice	No fence or wall to mount on; a boundary so slack it cannot be tensioned; runs long enough that cabling every node is impractical.	Short perimeters where one interrogator cannot be justified; intensity-based sensing where you need to know where along the line it happened.	Retrofitting to an existing fence; sites unwilling to carry the mechanical maintenance; boundaries that are irregular or frequently altered.	As the only means of detection where sightlines are blocked, fog is common or lighting is poor. It watches the approach; it does not feel the fence.
From Gandeevan	Prachir N100 node and M100 master — available.	Abhedya L100 is in field trials; Abhedya D100 is in design.	Not offered.	Not offered as a sensor. Sanchalan links your existing CCTV to perimeter events.

Read the full comparison for what each row means in practice, or see the products we build.