Do I Need a Safety Sensor on an Automatic Gate? Photocell Beams Explained

Short answer: yes. An automatic gate should have a photocell safety beam across the opening, so the gate stops or reverses if a person, child, pet or car is in its path while it closes. A pair of beams costs very little next to the motor: our SB-10 single beam sensor pair is ₹799, and every SGM-370 and SGM-550 kit, from ₹31,500, already has one obstacle sensor in the box. Prices are our live website prices, include GST, and delivery across India is free.

Why does an automatic gate need a safety sensor?

A sliding or swing gate is a heavy steel object driven by a motor. Our sliding motors are rated for gates of 600 kg to 2000 kg. Once you press the remote, the motor keeps moving the gate until it reaches the limit switch. It does not know that a child has run back for a ball or that the car behind yours has started to roll in.

Most people press the remote from inside the car or from the first floor, often without a clear view of the whole opening. A safety beam is the part that watches the opening for you. Without it, the only thing that stops a closing gate is the person holding the remote noticing in time.

In Indian homes the risk is real: children play in the driveway, two-wheelers squeeze through a half-open gate, and drivers often close the gate behind them as they reverse out. A beam turns all of these into a stop instead of an accident.

What is a photocell beam and how does it work?

A photocell safety beam is two small boxes. One is a transmitter that sends an invisible infrared beam. The other is a receiver that watches for it. They are mounted facing each other on either side of the gate opening.

1. While the beam reaches the receiver, the path is clear and the gate closes normally.
2. When anything breaks the beam, the receiver switches its relay output.
3. That output is wired to the safety or photo input on the gate motor's control board.
4. The control board stops the gate, or stops and reverses it, depending on how the board works and is set.

The beam only matters while the gate is closing. A beam broken while the gate is fully open usually just stops the gate from starting to close until the path is clear.

What does the SB-10 actually offer?

From its listing, the SB-10 single beam sensor comes as a pair (transmitter and receiver) with these points:

• Power: 12 to 24 V DC, drawing 15 mA on the receiver and 30 mA on the transmitter.
• Output: relay rated 1 A at 36 V, switchable between NO and NC with a jumper. It ships set to NO.
• Range: 10 metres outdoors and 20 metres indoors, far more than any house gate needs.
• Response: about 30 ms.
• Weather: IP55 sealed housing, rated for -25 to 55 degrees C, with anti-glare up to 50,000 lux so sunlight and car headlights do not trigger it.

Set the NO/NC jumper to whatever your control board's photo input expects. The motor manual or the board's terminal label tells you. If you are not sure, send us a photo of the board on WhatsApp before wiring.

Where should I fit the safety beam?

• Across the opening, close to the gate line. For a sliding gate, put the pair on the two pillars just inside the gate, so the beam covers the gap the gate is about to close.
• At about bumper or knee height. Around half a metre from the ground catches cars, scooters, adults and most children. Tall vehicles and very small children are the reason some sites add a second pair at a different height.
• Facing each other squarely. Align the two units carefully. A slightly crooked receiver gives random stops.
• Away from the gate's own path. On a swing gate, make sure the leaves do not pass through the beam as they open, or the gate will stop itself.
• With cable in conduit. Run the low-voltage cable in a pipe so it is not cut by the gate or by a gardener.

Is a beam enough on its own?

A beam watches one straight line. It cannot see a child standing exactly at the edge of the gate, beside the line, or someone touching the moving leaf. So treat it as the main safety part, not the only one:

• Add a warning light. The SF-2T warning light (₹850) flashes with a 110 dB buzzer while the gate moves. It runs on AC 220 V, DC 12 V or DC 24 V.
• Keep children away from the gate path and keep remotes out of their reach.
• Test the beam every month. Start closing the gate and walk through the beam. It must stop. Our sliding gate motor buying guide covers the other safety basics.
• Know the manual release. If the gate ever traps something, release the clutch with the supplied key and move the gate by hand.

Our swing operators list their own protection too: the ARM-3K listing mentions obstacle detection and auto-stop, and the SWM-700 lists a safety stop on obstacle detection. A beam across the opening is still worth adding. The swing gate motor buying guide covers swing layouts.

Which safety sensor or kit should I buy?

Product	What you get	Best for	Price
SB-10 single beam sensor	1 pair (transmitter + receiver), 12 to 24 V DC, IP55	Adding a beam to a gate motor you already have	₹799
SB-10 single beam sensor, pack of 3	Pack of 3, as listed	Installers and sites with several gates	₹2,999
SGM-370 with single beam sensor	600 kg sliding motor, 1 obstacle sensor, 2 remotes; no gear rack	New house gate up to 600 kg, rack bought by the metre	₹23,500
SGM-370 kit, 3 gear rails	600 kg motor, obstacle sensor, siren lamp, rails approx. 10 ft	Short house gate, everything in one box	₹31,500
SGM-550 kit, 8 gear rails	1200 kg motor, obstacle sensor, siren lamp, rails approx. 26 ft	Long, heavy gate at a kothi or farmhouse	₹41,500
SF-2T warning light	Strobe lamp with 110 dB buzzer	Warning people while the gate moves	₹850

The motor-only SGM-370, SGM-550, SGM-750 and SGM-1200 listings say the photocell sensor is bought separately, so add an SB-10 pair if you choose one of those. See every part in gate motor accessories, or plan a full setup with the Gate Builder. Prices for every motor are in the sliding gate motor price guide.

FAQ

Is a safety sensor compulsory on an automatic gate?

It is the most important safety part you can add, and we recommend it on every installation. A closing gate cannot see what is in its path; the beam can.

What happens when something breaks the beam?

The receiver switches its relay output, and the gate motor's control board stops the gate or stops and reverses it, depending on the board and its settings.

Can I add a photocell to a gate motor I already have?

Usually yes, if the control board has a photo or safety input and a 12 to 24 V DC supply for accessories. The SB-10 pair costs ₹799; send us a photo of your board if you are unsure.

At what height should a gate safety beam be fitted?

Around bumper or knee height, roughly half a metre from the ground, on the pillars just inside the gate line. Some sites add a second pair at another height.

Does sunlight affect a photocell beam?

Good beams filter it out. The SB-10 listing gives anti-glare up to 50,000 lux, so direct sunlight and headlights do not trigger it. Keep the lenses clean.

Is a triple beam sensor better for a gate?

Triple beam sensors such as the ABT-250 are made for boundary intrusion alarms, not gate safety. For that use, read the infrared beam sensor guide.

Prices are NavKar Systems website prices on 27 October 2026, inclusive of GST, and may change.