Using Laser Distance Finders

Author: Brian Rhodes, Published on Jun 04, 2012

Calculating correct distances can be a pain but are an essential part of properly estimated projects. For years, the tape measure has been a constant companion on site surveys, but even the simple task of taking measurements can be a time consuming, two man job - especially for longer distances. Does a better alternative exist? In this note we review laser distance meters, a simple handtool that we have found to be a great alternative to tape measures when taking measurements in the field.

Overview

The time it takes light to travel can be used to calculate distance. The longer it takes for a laser to bounce off of a remote target and return to the sending point, the farther away the target is located.

Laser distance finders, or 'rangefinders' are handheld, battery powered devices that use this principle to measure distance. These units emit a low power laser matched to a sensitive collector that measures minute amounts of reflected light. A very precise timer measures this loop many thousands of times in a second, and the time value is converted to read as a distance measure on the meter's display.

Common Features

While a wide variety of models exist, features common to most units can also be found in the example below:

Features like extended measurement distance (lengths exceeding 650' are common), area measurements, memory capacity, and enclosure durability all influence final cost. However, for most security installers the basic, most inexpensive models are sufficient.

Analysis

Pros

Get Video Surveillance News In Your Inbox
Get Video Surveillance News In Your Inbox

Quick: The speed that measurements are taken might be the biggest advantage of laser distance finders. When compared with the process of unreeling measuring tape, stepping off a distance with a wheel, or counting ceiling tiles, the laser unit is almost instantaneous. The term 'point and shoot' is often used to describe the process required to collect a measurement, and several measurements covering hundreds of feet can be taken in a minute or less.

Lightweight and small: The physical dimensions of a distance finder are small, approximately the same size as a multimeter. Devices can be easily carried on belt clips or in tool bags, and can be operated using only one hand.

Inexpensive: Laser distance finders can be purchased for under $100, and while more expensive than traditional tape measures, models are not so expensive they cannot be purchased as a common hand tool.

Accurate enough for most measurements: Early versions of laser distance finders were prone to being wildly inaccurate, but current models are accurate and precise to fractions of an inch. For example, this 650' distance model is accurate to +/- 0.04 inches at maximum measured length. The more significant concern for modern models is angularity error the operator introduces in holding the unit 'off-target'. In any case, for the rather coarse measurements taken during a site survey, the laser distance finder is sufficient for most video security work.

Cons

Hard to see in bright sunlight: The most common complaint of using laser distance finders are that finding the 'laser dot' can be difficult in brightly lit areas. While the ambient brightness and reflectivity do not affect the accuracy of the tool, it is easy to lose the dot location in sunlight flooded areas. A variety of tools exist to help reduce this problem, including 'laser enhancement glasses' that make the dot appear more intense in sunlight.

Hard to see at extreme distances: Along with brightness, successfully locating a 'laser dot' at extreme lengths can be difficult. The diameter of the laser dot is often 1/4" or less, and over hundreds of feet it can be very difficult to locate. Some 'high end' distance finders include a built-in camera with zoom to help with this. Some users may opt to fabricate a 'target', like we demonstrate in the video below, that simply provides a dark, high contrast target to bounce a beam from in the field.

Humidity, heat can affect accuracy: While modern units have been engineered to overcome the weaknesses of early models, certain environmental situations can affect unit performance. For example, heat influences beam divergence (expanding beam diameter) over distance and can distort the timing of beam travel. While this distortion may be an extremely minute amount,even a small visual disturbance can result in a significant distance error. Likewise, high humidity (the presence of moisture in the air) not seen with the naked eye can sometimes contains enough water vapor to introduce meter error. The best approach to take to prevent these errors are to read the unit manual and apply the meter only within environment parameters defined by the manufacturer.

Not all units are create equal: As with any manufactured device, the quality of components affect usability. Modern units are built with 'pulsed emitters' designed to minimize measurement error, but older 'fixed emitter' technology is still used in lower-cost alternatives. Because 'laser distance finder' is a generic term, care should be taken to select a unit with a proven history of use. This risk is often most significant when specifying units with extreme maximum distances (>800 feet) and multi-function units (Ultrasonic stud finder/laser distance finder combos) Fortunately, units built with good technology can be found even at the low-end of pricing. Simply reading product reviews on these units can go a long way in choosing the right unit.

Demonstration Video

Here is a quick video that introduces this tool and shows basic operation. While exact operation may vary from unit to unit, the function below is common to most tools in the category:

The measuring wheel is the most common alternative to laser meters. In a future post, we will review measuring wheels and compare.

Comments : PRO Members only. Login. or Join.

Related Reports on Tools

Pole Mount Camera Installation Guide on Apr 11, 2019
Poles are a popular but challenging choice for deploying surveillance cameras outdoors. Poles are indispensable for putting cameras at the right...
Silicon Valley Cybersecurity Insurance Startup Coalition Profile on Mar 20, 2019
Many industry people believe cybersecurity insurance is not worth it, as the voting and debate in our Cybersecurity Insurance For Security...
Large US University End-User Video Surveillance Interview on Mar 18, 2019
Schools have become targets in modern days of active shooters and terrorist fears. The need for video and access security is high. Universities...
Installation Course - REGISTRATION CLOSED on Mar 14, 2019
This is the last chance to register for the March Installation course. CLOSED This is a unique installation course in a market where little...
City Physical Security Manager Interview on Mar 14, 2019
This physical security pro is the Physical Security Manager for the City of Calgary. He is a criminologist by training with an ASIS CPP credential....
Security Installation Tools Guide - 22 Tools Listed on Feb 19, 2019
In this guide, we cover 22 tools that security installers frequently use. This is one part of our upcoming Video Surveillance...
Ideal SecuriTest IP Vs Unbranded IP Camera Install Tool Tested on Nov 21, 2018
In our recent IP camera installation tool shootout, multiple members questioned the Ideal SecuriTest IP's features compared to low-cost unbranded...
ISC East 2018 Mini-Show Final Report on Nov 16, 2018
This is our second (updated) and final show report from ISC East. ISC East, by its own admission, is not a national or international show, billed...
IP Camera Installation Tool Shootout - Avigilon, Axis, Ideal, Hanwha, Triplett, Veracity on Oct 23, 2018
Setting up IP cameras has historically been challenging, with techs often precariously using a laptop on a ladder or lift. Some options for install...
Integrator Laptop Guide on Oct 16, 2018
This 18-page guide provides guidance and statistics about integrator laptop use. 150 integrators explained to IPVM in detail about their laptops,...

Most Recent Industry Reports

H.265 Usage Statistics on Apr 19, 2019
H.265 has been available in IP cameras for more than 5 years and, in the past few years, the number of manufacturers supporting this codec has...
ACRE Acquires RS2, Explains Acquisition Strategy on Apr 19, 2019
ACRE continues to buy, now acquiring RS2, just 5 months after buying Open Options. One is a small access control manufacturer from Texas, the...
Access Control Course Spring 2019 - Last Chance on Apr 19, 2019
Register for the Spring Access Control Course. IPVM offers the most comprehensive access control course in the industry. Unlike manufacturer...
Riser vs Plenum Cabling Explained on Apr 18, 2019
You could be spending twice as much for cable as you need. The difference between 'plenum' rated cable and 'riser' rated cable is subtle, but the...
Verint Victimized By Ransomware on Apr 18, 2019
Verint, which is best known in the physical security industry for video surveillance but has built a sizeable cybersecurity business as well, was...
Milestone Drops IFSEC on Apr 18, 2019
Milestone has dropped out of Europe's largest annual security trade show (IFSEC 2019), telling IPVM that they "have found that IFSEC in EMEA no...
The Fastest Growing Video Surveillance Sales Organization Ever - Verkada on Apr 17, 2019
Verkada has the fastest growing video surveillance sales organization ever. In less than 2 years, they already have more salespeople in the US...
Door Operators Access Control Tutorial on Apr 17, 2019
Doors equipped with door operators, specialty devices that automate opening and closing, tend to be quite complex. The mechanisms needed to...
Securadyne CEO: IPVM 'Entertaining For An Ignorant Few' on Apr 16, 2019
Securadyne's CEO Carey Boethel is unhappy with IPVM's report - Failed Integrator Rollup, Securadyne Sells to Guard Giant Allied. Indeed, he...
Dahua Repositionable IR Multi-Imager Camera Tested on Apr 16, 2019
Dahua has released their first repositionable multi-imager camera, the Multi-Flex 4x2MP, claiming integrated IR, true WDR, and flexible...

The world's leading video surveillance information source, IPVM provides the best reporting, testing and training for 10,000+ members globally. Dedicated to independent and objective information, we uniquely refuse any and all advertisements, sponsorship and consulting from manufacturers.

About | FAQ | Contact