PIR Motion Sensor Guide: Placement, Range and Pet-Immune Models
Short answer: fit a PIR motion sensor high in a corner, about 1.8 to 2.2 m off the floor, looking across the path an intruder would walk, and away from windows, AC vents and heaters. Most indoor PIRs on our store cover about 12 m at a 110° angle. If you have a dog or cat, use the PIPE-10 pet-immune PIR (₹1,900), which is made to ignore pets under 25 kg. A standard wireless PIR for an alarm panel costs ₹899 to ₹949, and wired PIRs cost ₹1,199 to ₹1,599.
A door sensor tells you a door opened. A PIR tells you someone is moving inside, which catches an intruder who came through a window, a roof or a wall you did not think to protect. One well-placed PIR can watch a whole hall. This guide covers how they work, where to put them, what range to expect and which model suits your home, shop or office.
What is a PIR motion sensor and how does it work?
PIR stands for passive infrared. The sensor does not send out a beam; it watches for the infrared heat a human body gives off. Its lens splits the room into zones, and when a warm body moves from one zone to the next, the sensor signals the alarm. Two things follow from this. A PIR is best at catching someone walking across its view, and less quick when someone walks straight towards it. And anything that changes temperature fast, such as sunlight through a window or a heater switching on, can confuse it.
Where should you place a PIR motion sensor?
- Pick the path, not the room. Think where an intruder must walk: the passage from the back door, the hall between bedrooms, the route to the cash counter or locker. Aim the PIR across that path.
- Mount it in a corner, high up. A corner gives the widest view. The PIMS-43 listing gives the best height as 1.8 to 2.2 m, and the PIRW-T10 recommends about 2.2 m.
- Keep the view clear. Cupboards, curtains and tall plants block infrared. Glass does too, so a PIR cannot see through a window into the next room.
- Avoid heat and sunlight. Do not point it at windows that get direct sun, AC or heater outlets, geysers, kitchen stoves or ceiling fans blowing on curtains.
- Stay within radio range. For wireless PIRs, keep the sensor within range of the panel. The PIMS-43 listing advises keeping it within 12 m of the alarm panel for the best link.
- Walk-test. After pairing, walk across the room at normal speed and check the panel or app responds. Adjust the angle if it misses the edges.
How far can a PIR detect?
Range depends on the model and on the room. On our store, the PIPE-10 and PIRW-T10 list 12 m at 110°, the PIR-TY lists 9 to 12 m at 90°, and the ACJ-1008 PIR lists 15 m at 360°. Treat these as the best case in an open room. Furniture, partitions and a person walking directly at the sensor all shorten the real distance, so a long godown or showroom may need two PIRs facing from opposite ends.
Do I need a pet-immune PIR?
If a dog or cat roams the house while the alarm is armed, yes. A normal PIR sees a warm moving animal the same way it sees a person. The PIPE-10 uses a Fresnel lens designed to ignore pets under 25 kg, and its listing also mentions crawl detection, so a person crawling under the view is still caught. To get the most from it, do not aim it at sofas, beds or stairs your pet climbs, because a pet up high looks more like a person to any PIR. The PIPE-10 works only with a 433 MHz alarm panel; it does not have its own Wi-Fi app.
PIR motion sensors on our store
| Model | Type | Range and angle (from listing) | Best for | Price |
|---|---|---|---|---|
| PIMS-43 | Wireless 433 MHz | 110°; 2 AAA batteries, 18 to 24 months standby | Halls and rooms on a wireless alarm panel | ₹899 |
| PIMT-43 | Wireless | Wide angle; see product page | Rooms, offices, warehouses | ₹949 |
| PIPE-10 | Wireless 433 MHz, pet immune | 12 m, 110°; pets under 25 kg ignored; crawl detection | Homes with a dog or cat | ₹1,900 |
| PIR-TY | Wi-Fi (Tuya app), own alarm | 9 to 12 m, 90°; alarm over 80 dB; 5V USB power | One room or shop with no alarm panel | ₹1,900 |
| PIRW-12 | Wired | Up to 12 m | Wired zones on an alarm panel | ₹1,199 |
| PIRW-T10 | Wired, dual element | 12 m, 110°; 12V DC; NC alarm and tamper outputs; adjustable sensitivity; not pet immune | Offices and shops with a wired panel | ₹1,599 |
| ACJ-1008 PIR | Wireless, for ACJ-1008 only | 15 m, 360°; tamper switch; low-battery indication | Large sites on the ACJ-1008 panel | ₹2,800 |
Which PIR should you buy?
- You have an ACJ-400, 402, 405 or 407 panel: start with the PIMS-43 (₹899). The ACJ-400 and ACJ-407 kits already include one PIR, so you only buy extras for other rooms. Send us your panel model on WhatsApp and we will confirm pairing.
- You have a pet: the PIPE-10 (₹1,900) on a 433 MHz panel.
- You have no alarm panel: the PIR-TY (₹1,900) sounds its own alarm and sends Tuya app alerts over Wi-Fi. For a louder siren, Combo-CN161 (₹4,950) pairs a Tuya Wi-Fi PIR with a Tuya Wi-Fi siren, 2 remotes and a 12V supply.
- You are wiring a new office or shop: the PIRW-T10 (₹1,599) gives NC alarm and tamper outputs and adjustable sensitivity; the PIRW-12 (₹1,199) is the simpler wired option.
- Your site runs on the ACJ-1008: use only its own PIR (₹2,800). See the ACJ-1008 guide.
- You want to watch a yard or farm outdoors: an indoor PIR is not the right tool. Look at infrared beam sensors for boundaries.
To see how a PIR fits with door sensors and a siren in a full system, read the Wi-Fi + GSM home security alarm guide, or pick an ACJ panel with our ACJ-400 vs 405 vs 407 comparison. Browse all models in PIR motion sensors, or plan sensors room by room in the Security System Builder.
FAQ
What is the best height to mount a PIR sensor?
About 1.8 to 2.2 m from the floor, in a corner. The PIMS-43 listing gives 1.8 to 2.2 m and the PIRW-T10 recommends about 2.2 m.
Why does my PIR give false alarms?
The usual causes are direct sunlight, an AC or heater blowing into its view, curtains moving in a fan's draught, or a pet. Move or re-angle the sensor, or switch to a pet-immune model.
Can a PIR sensor see through glass?
No. Glass blocks the infrared a PIR looks for, so it will not detect movement on the other side of a window.
Will my dog set off the alarm?
With a normal PIR, it can. The PIPE-10 is designed to ignore pets under 25 kg, provided the pet cannot climb up into the upper part of its view.
Can a PIR motion sensor work without an alarm panel?
Most cannot. The PIMS-43, PIPE-10 and wired models need a panel. The PIR-TY has its own alarm sound and Wi-Fi app, so it works alone.
How long do PIR sensor batteries last?
The PIMS-43 listing gives 18 to 24 months on two AAA alkaline batteries. Wired PIRs need no battery.
Prices are NavKar Systems website prices on 27 October 2026, inclusive of GST, and may change.
