A laser rangefinder is an instrument that uses a laser to accurately measure the distance to a target. The laser rangefinder emits a very thin laser beam to the target when it is working, and the photoelectric element receives the laser beam reflected by the target. The timer measures the time from the emission to the reception of the laser beam, and calculates the distance from the observer to the target. The laser rangefinder is light in weight, small in size, simple in operation, fast and accurate, and its error is only one fifth to several hundredths of other optical rangefinders.

principle

1. Using the principle of infrared ranging or laser ranging

The principle of ranging can basically be attributed to measuring the time required for the light to travel to and from the target, and then pass

Laser rangefinder

The distance D is calculated from the speed of light c = 299792458m/s and the atmospheric refractive index n. Because it is difficult to measure time directly, it is usually to measure the phase of the continuous wave, which is called a phase-measuring rangefinder. Of course, there are also pulsed rangefinders, typically WILD's DI-3000.

It should be noted that the phase measurement does not measure the phase of the infrared or laser, but measures the phase of the signal modulated on the infrared or laser. The construction industry has a handheld laser rangefinder for house measurements that works the same way.

2. The plane of the measuring object must be perpendicular to the light

Usually, precise ranging requires the cooperation of a total reflection prism, and the rangefinder used for house measurement is directly measured by the reflection of a smooth wall, mainly because the distance is relatively close, and the signal strength of the reflected light is large enough. It can be known from this that it must be vertical, otherwise the return signal is too weak and the precise distance cannot be obtained.

3. The plane of the object can be measured as diffuse reflection

Usually it is also possible. In practical projects, a thin plastic plate will be used as a reflective surface to solve the problem of serious diffuse reflection.

4. The accuracy of ultrasonic ranging is relatively low, and the use is relatively small.

5. The accuracy of the laser rangefinder can reach 1 mm error, which is suitable for various high-precision measurement purposes.

Shop

Here are a few things to consider when buying a rangefinder:

1. Measuring range

2. Measurement accuracy

3. The occasion of use

Basically it is divided into the following situations:

a) Only need to measure the distance within a few meters or a dozen meters,

And when the accuracy requirement is not high.

Recommendation - "Ultrasonic rangefinder" can be used.

Remarks - The measurement effect of the ultrasonic rangefinder is greatly affected by the environment, and the stability and directionality are worse than that of the laser rangefinder, but the price is relatively cheap, suitable for indoor measurement.

b) The measurement distance is not long, and it is mostly used indoors, with high precision requirements.

Recommendation - Optional "Handheld Laser Rangefinder".

Remarks - The handheld laser rangefinder is most suitable for indoor use, and the measurement accuracy and effect are very good.

(If the user needs to detect in an outdoor environment, it is recommended to use a professional laser sight and reflector to achieve the expected range and effect.)

c) The measurement distance is long, and it is mostly used for outdoor use.

Suggestion - buy "telescopic laser rangefinder" (ie: laser rangefinder telescope)