The World's Smallest PIRs

By Brian Rhodes, Published on Jul 02, 2013

Passive InfraRed (PIR) motion detectors are critical in many security systems, yet they are often considered ugly or intrusive.

Despite being indispensable, and even required by code in certain applications, they are difficult to hide and frequently look like plastic bricks. However, Visonic has a line of low-profile discrete sensors in the Spy series of PIRs. In this note, we examine these sensors, discuss applications and pricing.

Weaknesses of Traditional PIRs

PIR Motion Sensors are used in several types security systems; from intrusion alarms, to Electronic Access Control, and even video surveillance. Despite different applications, traditional sensors are big, unsightly, and designed for 'general purpose use.' Even specialty sensors (like RTE PIRs) are designed to be hung on the door frame in the same way, regardless of the impact to appearance of vulnerability of the sensor to tampering. Considering that 'traditional PIRs' are a common source of 'false alarms' and can even be misused by outsiders to unlock doors, choosing the right PIR for the job makes sense.


Visonic SPY Series

The most distinctive difference with SPY PIRs compared to other types is the smaller size and mount. Most PIR sensors are large and mount flush with walls or door frames. Visonic's line is recessed into the mounting surface, with the majority of the sensor fitting inside the hole (2 3/4" deep), and measure ~3/4" in diameter.

This is a security benefit in reducing tamper risk, but also an aesthetic requirements that most sensors fail at meeting. Rather than white or beige colored boxes hanging on a wall, the SPY is discrete and less obtrusive.


Get Notified of Video Surveillance Breaking News
Get Notified of Video Surveillance Breaking News

Sensor Details

The line includes four separate types of sensors, each designed to detect movement in a different pattern or range:

The manufacturer offers application suggestions based on the detection range and on the typical detection requirements of movement:

  • Spy 1: Corridor - A narrow, long ranged sensor ideal for detecting movement in glassed corridors or hallways where other motion sensors may 'false alarm' based on light changes our movement in adjacent areas.
  • Spy 2: Large room: A moderately wide, but deep range sensor, useful for covering long rooms from a wall mounted location.
  • Spy 3: Wide room: The widest range sensor, covering up to 100 degrees of width.
  • Spy 4: Door RTE or Tripwire: A specialty unit designed specifically for RTE applications, but also can be used in corridors as a virtual 'trip line'

Detection Regions Not Adjustable

However, while the different SPY models are useful in a range of situations, detection regions are not adjustable or maskable - a feature seen in several 'high end' PIRs. 

Not Pet Immune - Commercial/Industrial Only

Another potential dealbreaker is that SPY series offers no 'pet immunity', that is ignoring moving objects with a small mass. This is useful in residential applications where pets may roam hallways/rooms at night when the alarm system is armed. Omitting this feature limits the SPY series to commercial or industrial types of systems

Price Comparison

The Visonic SPY series ranges between $40 - $50 online, depending on the particular unit. This is more expensive than many 'Pet Immune' intrusion alarm style PIRs (ie: ~$20), but are less expensive or roughly equal to specialty sensors like RTE or curtain types.

When false alarms are a problem, many suggest using costly 'dual technology' PIRs that require more than one (integrated) unit sensor to detect motion before tripping. 'Dual Tech' sensors can cost $75 up to $250, and the mount flexibility/ tighter sensing range of a SPY PIR may ultimately result in similar accuracy with a lower cost solution than a dual technology PIR.

Application Advantages

The benefit of using smaller, recessed sensors is obvious in many situations. Take the example below, where motion up the stairs needs to be detected, but motion outside of the stairwell is not an alarm condition:

Rather than hanging a traditional PIR on the most convenient wall, which is considerable distance from the foot of the staircase, a SPY can be hung adjacent to the rail and shoot a tight curtain only the width of the staircase. Rather than detecting motion over many square feet, the detection area is tight and only just a few feet surrounding stair access.

Biggest Strength

Because the SPY series is small and recessed, sensors can readily be inserted into walls and doorframes, even at heights that would be risky for 'traditional' larger and flush mounted units. The physical orientation and positioning of the sensor is key to accuracy, and while traditional sensors are limited in where they can be placed, SPY allows for placing PIRs into more useful positions.

Just as camera position plays a key role in surveillance effectiveness, sensor position for PIRs is key for prime detection. If the 'false alarm' risk can be cut by simply sticking the right detection sensor in an ideal location, using SPY could improve performance, Intrusion, CCTV, or EAC system alike.

Comments (0) : Members only. Login. or Join.

Related Reports

Cheap Camera Problems at Night on Feb 19, 2020
Cheap cameras generally have problems at night, despite the common perception...
Door Fundamentals For Access Control Guide on Aug 24, 2020
Doors vary greatly in how difficult and costly it is to add electronic access...
Integrated IR Camera Shootout 2020 - Avigilon, Axis, Bosch, Dahua, Hanwha, Hikvision, Panasonic, Uniview, Vivotek on Jan 30, 2020
The best and worst cameras tested in this IPVM shootout showed major...
Multipoint Door Lock Tutorial on Jan 23, 2020
Despite widespread use, locked doors are notoriously weak at stopping entry,...
Injes Tiny Temperature Terminal Tested on Jul 17, 2020
While temperature terminals have trended bigger, the Injes DFace801 is...
The Problem With Fever Detecting Thermal Sunglasses on Apr 15, 2020
While the media has promoted using thermal sunglasses to detect fevers, this...
Coronavirus Hits Manufacturers, Standing Now, Worse To Come on Apr 06, 2020
Coronavirus is hitting security manufacturers, though overall modestly for...
K7 Wall Mounted IR Temp Gun Tested on Jun 26, 2020
The original K3 model was missing a number of important features but the...
Infinova, March Networks and Swann H1 2020 Financials Examined on Sep 02, 2020
While Dahua and Hikvision, helped by fever camera sales, are recovering from...
New: Mobile Access Proxy Releases 'World's Smallest Mobile Reader' on Mar 04, 2020
Mobile access provider Proxy claims its new Nano is 'the world’s smallest...
Spectron IR Thermal Fever Screening System Examined on Apr 14, 2020
Most are quick to avoid "fever screening" and "medical" labels, but...
Access Credential Form Factor Tutorial on Feb 10, 2020
Deciding which access control credential to use and distribute, including...
Facial Recognition: Weak Sales, Anti Regulation, No Favorite, Says Security Integrators on Jul 07, 2020
While facial recognition has gained greater prominence, a new IPVM study of...
Temperature Tablet Shootout - Dahua, Hikvision, ZKTeco, TVT + 5 More on Sep 30, 2020
Temperature tablets, aka terminal or stations, have emerged as a 'low-cost...
Drain Wire For Access Control Reader Tutorial on Sep 23, 2020
An easy-to-miss cabling specification plays a key role in access control, yet...

Recent Reports

Consultants Online Show LIVE Today! on Oct 27, 2020
IPVM's 7th online show will feature 20+ consultants and recruiters presenting...
Eagle Eye Networks Raises $40 Million on Oct 27, 2020
Eagle Eye has raised $40 million aiming to "reinvent video...
Hikvision Q3 2020 Global Revenue Rises, US Revenue Falls on Oct 27, 2020
While Hikvision's global revenue rises driven by domestic recovery, its US...
VICE Investigates Verkada's Harassing "RawVerkadawgz" on Oct 26, 2020
This month, IPVM investigated Verkada's sexism, discrimination, and cultural...
Six Flags' FDA Violating Outdoor Dahua Fever Cameras on Oct 26, 2020
As Six Flags scrambled to reopen parks amid plummeting revenues caused by the...
ISC Brasil Digital Experience 2020 Report on Oct 23, 2020
ISC Brasil 2020 rebranded itself to ISC Digital Experience and, like its...
Top Video Surveillance Service Call Problems 2020 on Oct 23, 2020
3 primary and 4 secondary issues stood out as causing the most problems when...
GDPR Impact On Temperature / Fever Screening Explained on Oct 22, 2020
What impact does GDPR have on temperature screening? Do you risk a GDPR fine...
Security And Safety Things (S&ST) Tested on Oct 22, 2020
S&ST, a Bosch spinout, is spending tens of millions of dollars aiming to...
Nokia Fever Screening Claims To "Advance Fight Against COVID-19" on Oct 22, 2020
First IBM, then briefly Clorox, and now Nokia becomes the latest Fortune 500...
Deceptive Meridian Temperature Tablets Endanger Public Safety on Oct 21, 2020
IPVM's testing of and investigation into Meridian Kiosk's temperature...
Honeywell 30 Series and Vivotek NVRs Tested on Oct 21, 2020
The NDAA ban has driven many users to look for low-cost NVRs not made by...
Ubiquiti Access Control Tested on Oct 21, 2020
Ubiquiti has become one of the most widely used wireless and switch providers...
Avigilon Aggressive Trade-In Program Takes Aim At Competitors on Oct 20, 2020
Avigilon has launched one of the most aggressive trade-in programs the video...
Mexico Video Surveillance Market Overview 2020 on Oct 20, 2020
Despite being neighbors, there are key differences between the U.S. and...