Ultrasonic Sensor features Amazing 1 mm Resolution

MaxBotix Inc., has released the HRLV-MaxSonar-EZ for sale to the public. The HRLV-MaxSonar-EZ sensor line features 1 mm resolution, target size compensation for improved accuracy, simultaneous automatic multi-sensor operation, superior rejection of outside noise sources, internal temperature compensation, optional external temperature compensation, a 5-meter range, and adds TTL serial output to the RS232, pulse width, and analog voltage outputs that are already standard on other MaxSonar products.

The 1 mm resolution is so stable, that when measuring typical objects at a distance of one meter, the readings do not change by more than 1 mm. The best stability is available with the TTL and RS232 serial outputs with a typical error of ± 0.1% at one meter. The pulse width has a stability of ± 0.2 %, while the rail to rail analog voltage output has a resolution of 5 mm.

Most low cost ultrasonic rangefinders will report the range to smaller size targets as farther than the actual distance. In addition, they will also report the range to larger size targets as closer than the actual distance. The HRLV-MaxSonar-EZ sensor line correctly compensates for target size differences. This means that, if an object is large enough to be detected, the sensor will report the same distance regardless of target size.

Other ultrasonic rangefinders will fail when used with other ultrasonic sensors nearby. By comparison, the HRLV-MaxSonar-EZ sensors can be used with other sensors in close proximity. Other nearby ultrasonic sensors will have little to no affect on the reported range of the HRLV-MaxSonar-EZ sensors. The noise filtering of the HRLV-MaxSonar-EZ is now even better than the previous MaxSonar products, and will work in the presence of many more noise sources and outside noise sources with higher amplitudes. Most range readings are accurately reported, but if the range readings are affected, the effect is typically less than 2 cm.

The HRLV-MaxSonar-EZ sensor allows for accurate temperature compensation. The speed of sound changes up to 0.6% per degree centigrade. To compensate for this effect the sensor must monitor the changes to air temperature, while ignoring self-heating. Self-heating is an issue with internal temperature sensors, where the temperature increase is typically 2 to 5 degrees centigrade. If ignored, this will cause a drift of the reported range of up to 3%. Alternatively, when using an external temperature sensor, it will not be affected by self-heating of the main sensor electronics. The HR-MaxTemp is an external temperature sensor that can be easily connected to an HRLV-MaxSonar sensor. Once connected, the HRLV-MaxSonar sensor will auto detect the presence of the external temperature sensor, and it will accurately compensate for temperature effects. The HR-MaxTemp is available as an option as an non-assembled kit for $4.95 (MSRP).

The HRLV-MaxSonar-EZ comes with the easy to use outputs and standard pin configuration of the previous MaxSonar products. In addition to the three standard sensor outputs of RS232 serial, Analog Voltage, and Pulse Width, there is now a user selectable TTL serial output.

Similar ultrasonic products may have frequent side lobe detection and can even falsely trigger on objects behind or to the sides of the sensor. The HRLV-MaxSonar-EZ offers a controlled beam that is designed to reject small objects (clutter) outside of the central beam area and provides a long range sensitivity without detecting frivolous or unwanted targets. The HRLV-MaxSonar-EZ is 100% factory calibrated and tested before it is bagged and shipped. This ensures proper sensor operation and consistent performance from sensor to sensor.

The final assembly is a small unit less than 1 cubic inch, weighs 4.3 grams, and operates from 3 V to 5 V.

Contact:

Scott Wielenberg

Operations Manager

MaxBotix, Inc.

Brainerd, MN, USA

Tel.: 1-218-851-5941

E-mail: Scott@maxbotix.com