Extech Distance Meter

Laser Distance Meters are terrific and affordable alternatives to a tape measure for distance measurements. They offer the convenience of being able to make measurements without a second person to hold the measuring tape. Easily measure hard-to-access areas, like high ceilings or depths such as an elevator shaft or well, without climbing a ladder. As distance meters have evolved, features have been added to make them useful in performing calculations and in industries such as construction and sports like golf and hunting.

Features to look for in a Laser Distance Meter

• Look at the max distance specification and make sure it covers the desired range
• Calculation capabilities reduce estimating errors - let the meters do the math
  • Rectangular and triangular areas
  • Volume of a room
  • Angles in a triangle with measurements from three sides
  • Various types of Pythagoras functions. With Pythagoras’ theorem functions, you can find a distance with two auxiliary measurements, such as building height or width measurements. It is helpful to use a tripod for a height measurement that uses two or three measurements.
• Bluetooth or similar for PC communications
• Tilt sensor permits quick and simple measure tilt measurements. The inclination sensor also allows you to measure absolutely horizontally or measure past obstructions (horizontal distance). They help with leveling, height tracking, and measuring around obstacles.
• Compass. The compass feature lets you know the view or direction as you make measurements. This is useful indoors to set the building plans in the correct direction. It is also useful to know the correct direction when you calculate the efficiency for a solar panel.

General tips when using distance meters

• Choose a target that is flat, hard and smooth
• Use a piece of cardboard or similar material if the target size needs to be increased
• Always measure perpendicular to the target. Do not point at an angle
• Ultrasonic.Speed of sound increases with higher temperature and to a small extent speed increases at higher humidity. Ultrasonic distance meters compensate for temperature by including an ambient temperature sensor. Ultrasonics have a beam angle. Best analogy is a flashlight pointed at a wall. The cone increases and decreases as one moves away or comes closer. When using ultrasonics for long distances care must be taken not to have objects within the operating beam angle. Larger target sizes are needed at longer distances.
• Lasers have a narrow beam unlike ultrasonics. They can be affected, however, by bright ambient light or bad target reflectivity. Measuring errors can also occur when measuring to colorless liquids, glass, styrofoam or semi-permeable surfaces or when aiming at high gloss surfaces. Against dark surfaces the measuring time increases.

How does a distance meter work?
Distance meters operate on the principle of time of flight. Ultrasonic distance meters will excite a piezo crystal with high voltage low amperage to create a sound pulse in the kHz range. The time taken for the pulse to make a round trip to the target is measured. The speed of sound is known and so the distance can be calculated. Similarly laser distance meters send a pulse of light, however light pulses are much faster requiring high speed timers.

Take a look at an Extech laser distance meter