Laser distance measuring devices, also known as laser distance meters and laser distance finders, use laser light bounced off a fixed surface to determine the distance from a fixed reference point on the unit to the target at which the device is aimed.
A handy pocket electronic tool, they allow precise measurements of distances up to several hundred feet. The devices eliminate the issue of obstructions in the path of space being measured. What’s more, they allow measurements to be make in places where it might be dangerous to tread--high ceilings, over water, or wherever a ladder and traditional tape measure would be inconvenient or impossible. Contact points can include the front edge, the rear edge, the threaded bushing on the back side (used for supporting the unit on a tripod), and a fold-out extension.
As the operator cycles through the functions, an LCD display on the unit shows a graphic of the type of measurement being taken (in one , two, or three dimensions) and a place holder for each measurement to be taken, along with another place holder for the result.
Laser units measure more than linear distance. Many units can calculate area of a room or space, cube and cylindrical volume, indirect horizontal and vertical distances where the target is obstructed or there is no direct access to the target (e.g. on a wall on the façade of a building), indirect measurements on ceilings, and trapezoidal area--useful to measure the length of a roof. A laser distance finder can also save time and boost accuracy when setting out and marking positions for stud framing or other stake-outs.
Look for these differentiating factors: measurable distance, degree of accuracy, number of measuring modes, memory (number of measurements held), whether the unit supports Pythagoras functions for indirect measurement, inclination sensor (which enables height tracking, use of device as digital level/angle finder, and indirect horizontal distance measurement when line of sight is blocked), side viewfinder which helps in bright sunshine, screen options to optimize indoor and outdoor onscreen readout; type of battery; whether dust and splash proof (to IP54 standard), tripod mount, and Bluetooth technology.
Laser devices offer either single or continuous measuring mode. Single measurement is essentially a point-and-click at the target. Continuous measuring supports rapid updating (several times per second) of the measured distance as the device operator homes in on the target and then presses the button to freeze the measurement on the display. A laser device can also be used to home in on a designated distance.
The devices allow for
adding and subtracting distances. Adding is handy for determining the total
linear length of components such as molding, conduit, or fencing. Subtracting
would be useful in figuring out the distance between the underside of a duct
and the ceiling, eliminating the need to climb a ladder or fit into a tight
space with a measuring tool.
Some units feature Bluetooth technology for exporting data, Many are dust tight, others are water-protected, and several carry an IP rating.
Street prices range from around $50 for a basic unit to several
hundred dollars, depending upon measuring range and advanced features. Most
manufacturers offer a range of units—the more features, of course, the higher
1/ With a generously sized screen, the Hilti PD-E Laser Range Meter (www.us.hilti.com) features an optical sight on the side of the device for measuring distances greater than 30 feet; this is also handy for outdoors and when the laser spot is difficult to see or completely out of sight lines. The unit has rubber protection on all edges, a sensor automated backlight, an inclination sensor for fast indirect measurement, E-paper technology for enhanced readability in bright light, and LED reference indicators. The tool can measure from five different reference points and includes a fold-out spike that makes it easy to take measurements in inside corners. A “favorites bar” provides quick access to the most frequently used functions.
2/ The Leica DISTO™ E7400x (http://disto.leica-geosystems.us/) is a ruggedized unit that is IP 65 certified, with
housing and keypad that are dust tight and jet water protected. The unit has been tested to survive drops onto hard surfaces from up to six feet. It has an integrated 360º tilt sensor, it incorporates fiberglass-reinforced plastic bracing on the interior, and the solid rubber components protect the measuring elements against damage from drops. The unit measures from the front edge, back edge, and – using the integrated endpiece connected to the circuit board – from two additional reference points. When the endpiece is open to 90 degrees, the device measures from the back edge; if the endpiece is flipped open to 180 degrees, the unit measure it measures from the furthest edge, which is useful when measuring from an inside corner. A thread on the base allows for connection of the device to a tripod.
3/ Powered by a rechargeable Li-ion battery, the Bosch GLM 100 C Laser Measure with Bluetooth® wireless technology (www.boschtools.com) performs measurements at lengths up to 330 feet and angle measurements in two axes. The unit syncs with a free mobile measurement app to instantly transfer measurements from the device to smart phones or tablets (Android devices with Bluetooth 2.1/Bluetooth 3.0 and Apple iOS devices with Bluetooth Smart technology). Utilizing the unit’s measurement camera app, a user has the ability to sketch or overlay digital measurements onto jobsite photos taken with a smartphone. The device, which sports a tripod thread and an illuminated flip display with a tilt screen that supports reading and interpreting in all directions, can also be remotely controlled from a smartphone or tablet. In addition, Bosch’s GLM Transfer software (also free) supports transfer of measurement data via USB to the user’s Windows PC. Measured values are assigned a date and time stamp.
4/ The Spectra QM 55 (Trimble Navigation Limited, (www.spectralasers.com), a compact rugged unit designed for indoor use, features generous overmold and electronic isolation and incorporates a signal strength indicator for accuracy. Featuring nine types of measurements, and four reference points, it sports engineered plastics, generous overmold, and electronic isolation for drop protection up to five feet. The bright illuminating display supports reading in dim lighting. The illuminated display operates by a dedicated button, eliminating the need to scroll through menus to turn it off in bright lighting, helping to prolong the battery charge.
5/ Stanley TLM65 Laser Distance Measurer (www.stanleytools.com) is a lightweight compact point-and click unit that measures distance and calculates area and volume. Accurate to 1/8 inch, it’s a basic 2-button unit. One button activates on/off and continuous measuring; the other is pressed to calculate area/volume/units. The unit includes a handy continuous measurement function, enabling easy accurate location of a specific distance from the target.