HRLV-MaxSonar
®
- EZ
™
Series
HRLV-MaxSonar - EZ Series
High Resolution, Low Voltage Ultra Sonic Range Finder
MB1003, MB1013, MB1023, MB1033, MB1043
The HRLV-MaxSonar-EZ sensor line is the most cost-effective solution for applications
where precision range-finding, low-voltage operation, space saving, and low-cost are
needed. This sensor component module allows users of other more costly precision
rangefinders to lower the cost of their systems without sacrificing performance.
Additionally, this sensor line allows cost-sensitive designers to choose this precision sensor
as a performance upgrade over other lower performance sensors.
The HRLV-MaxSonar-EZ sensor line provides high accuracy and high resolution ultrasonic proximity detection and
ranging in air, in a package less than one cubic inch. This sensor line features 1-mm resolution, target-size and
operating-voltage compensation for improved accuracy, superior rejection of outside noise sources, internal speed-
of-sound temperature compensation and optional external speed-of-sound temperature compensation. This
ultrasonic sensor detects objects from 1-mm to 5-meters, senses range to objects from 30-cm to 5-meters, with large
objects closer than 30-cm typically reported as 30-cm. The interface output formats are pulse width, analog voltage,
and serial digital in either RS232 or TTL. Factory calibration is standard.
®
™
Precision Ultrasonic Range
Sensing
•
Range-finding at a fraction of the
cost of other precision rangefinders
•
Reading-to-reading stability of
1-mm at 1-meter is typical
•
Accuracy is factory-matched at
1-meter to 0.1% providing a typical
large target accuracy of 1% or better
for most voltages and uses
1
•
Calibrated acoustic detection zones
allows users to choose the part
number with the detection zone that
matches their specific application
•
Compensation provided for target
size variation and operating voltage
range
•
Internal temperature compensation is
standard
•
Optional external temperature
compensation
Easy to use Component
Module
•
Stable and reliable range readings
and excellent noise rejection make
the sensor easy to use
•
Easy to use interface with distance
provided in a variety of outputs
•
Target size compensation provides
greater consistency and accuracy
when switching targets
•
Sensor automatically handles
acoustic noise
1,2
•
Sensor ignores other acoustic noise
sources
•
Small and easy to mount
•
Calibrated sensor eliminates most
sensor to sensor variations
•
Very low power ranger, excellent for
multiple sensor or battery based
systems
•
Object proximity detection from
1-mm to 5-meters
•
Resolution of 1-mm
•
Distance sensor from 30-cm to
5-meters
•
Excellent
2
Mean Time Between
Failure (MTBF)
•
Triggered operation yields a
real-time
•
100mS measurement cycle
•
Free run operation uses a 2Hz filter,
with 100mS measurement and
output cycle
•
Operating temperature range
from -15°C to +65°C, provided
proper frost prevention is employed
•
Operating voltage from 2.5V to 5.5V
•
Nominal current draw of 2.5mA at
3.3V, and 3.1mA at 5V
Applications & Uses
Bin level measurement
Proximity zone detection
People detection
Robots ranging sensor
Autonomous navigation Distance
measuring
•
Long range object detection
Notes:
1
Users are encouraged to evaluate the
sensor performance in their
application.
2
Range Outputs
•
Pulse width, (1uS/mm)
•
Analog Voltage, (5mm resolution)
•
Serial, (RS232 or TTL, where TTL
format by solderable jumper or
volume orders available as no-cost
factory installed jumper)
Very Low Power
Requirements
•
Wide, low supply voltage
requirements eases battery powered
design
•
Low current draw reduces current
drain for battery operation
•
Fast first reading after power-up
eases battery requirements
•
•
•
•
•
General Characteristics
•
Low cost ultrasonic rangefinder
•
Sensor dead zone virtually gone,
•
Size less than 1 cubic inch with easy
mounting
By design.
MaxBotix
®
Inc.
Copyright 2005 - 2012 MaxBotix Incorporated
Patent 7,679,996
MaxBotix Inc., products are engineered and assembled in the USA
Page 1
Web:
www.maxbotix.com
PD11721d
HRLV-MaxSonar
®
- EZ
™
Series
Applications & Uses Cont.
•
Automated factory systems
•
This product is not recommended as
a device for personal safety
•
Designed for protected indoor
environments
•
Motion detectors
•
Limited tank level measurements
•
Box dimensions
•
Environments with acoustic and
electrical noise
•
Height monitors
_______________________________________________________________________________________________________________________________________
®
™
HRLV-MaxSonar -EZ Pin Out
Pin 1- Temperature Sensor Connection:
Leave this pin unconnected if an external
temperature sensor is not used. For best accuracy, this pin is optionally connected to the HR-
MaxTemp temperature sensor. Look up the HR-MaxTemp (MB7955, MB7956, MB7957,
MB7958, MB7959) temperature sensor for additional information.
Pin 2- Pulse Width Output:
This pin outputs a pulse width representation of the distance
with a scale factor of 1uS per mm. Output range is 300uS for 300-mm to 5000uS for 5000-
mm. Pulse width output is up to 0.5% less accurate then the serial output.
Pin 3- Analog Voltage Output:
On power-up, the voltage on this pin is set to 0V, after
which, the voltage on this pin has the voltage corresponding to the latest measured distance.
This pin outputs an analog voltage scaled representation of the distance with a scale factor of (Vcc/5120) per 1-mm. The
distance is output with a 5-mm resolution. (This output voltage is referenced to GND, Pin 7.) The analog voltage output
is typically within ±10-mm of the serial output.
Using a 10bit analog to digital convertor, one can read the analog voltage bits (i.e. 0 to 1024) directly and just multiply the
number of bits in the value by 5 to yield the range in mm. For example, 60 bits corresponds to 300-mm (where 60 * 5 =
300), and 1000 bits corresponds to 5000-mm (where 1000 * 5 = 5000-mm).
For users of this output that desire to work in voltage, a 5V power supply yields~0.977 mV per 1 mm. Output voltage
range when powered with 5V is 293mV for 300-mm, and 4.885V for 5000-mm.
Pin 4- Ranging Start/Stop:
This pin is internally pulled high. If this pin is left unconnected or held high, the sensor will
continually measure and output the range data. If held low, the HRLV-MaxSonar-EZ will stop ranging. Bring high for
20uS or longer to command a range reading.
Real-time Range Data:
When pin 4 is low and then brought high, the sensor will operate in real time and the first reading
output will be the range measured from this first commanded range reading. When the sensor tracks that the RX pin is low
after each range reading, and then the RX pin is brought high, unfiltered real time range information can be obtained as
quickly as every 100mS.
Filtered Range Data:
When pin 4 is left high, the sensor will continue to range every 100mS, but the output will pass
through a 2Hz filter, where the sensor will output the range based on recent range information.
Pin 5-Serial Output:
By default, the serial output is RS232 format (0 to Vcc) with a 1-mm resolution. If TTL
output is desired, solder the TTL jumper pads on the back side of the PCB as shown in the photo to the right.
For volume orders, the TTL option is available as no-cost factory installed jumper. The serial output is the
most accurate of the range outputs. Serial data sent is 9600 baud, with 8 data bits, no parity, and one stop bit.
V+ Pin 6 - Positive Power, Vcc:
The sensor operates on voltages from 2.5V - 5.5V DC. For best operation, the sensor
requires that the DC power be free from electrical noise. (For installations with known dirty electrical power, a 100uF
capacitor placed at the sensor pins between V+ and GND will typically correct the electrical noise.)
GND Pin 7 – Sensor ground pin:
DC return, and circuit common ground.
———————————————————————————————————————————————————————–————————————
About Ultrasonic Sensors
Our ultrasonic sensors are in air, non-contact object detection and ranging sensors that detect objects within an area. These
sensors are not affected by the color or other visual characteristics of the detected object. Ultrasonic sensors use high
frequency sound to detect and localize objects in a variety of environments. Ultrasonic sensors measure the time of flight
for sound that has been transmitted to and reflected back from nearby objects. Based upon the time of flight, the sensor
then outputs a range reading.
MaxBotix
®
Inc.
Copyright 2005 - 2012 MaxBotix Incorporated
Patent 7,679,996
MaxBotix Inc., products are engineered and assembled in the USA
Page 2
Web:
www.maxbotix.com
PD11721d
HRLV-MaxSonar
®
- EZ
™
Series
HRLV-MaxSonar
®
-EZ
™
Auto Calibration
Each time the HRLV-MaxSonar-EZ takes a range reading, it calibrates itself. The sensor then uses this data to range
objects. If the temperature, humidity, or applied voltage changes during sensor operation; the sensor will continue to
function normally over the rated temperature range while applying compensation for changes caused by temperature and
voltage.
Sensor Operation: Free-Run
When operating in free run mode, the HRLV-MaxSonar-EZ sensors are designed to be used in a variety of indoor
environments. Most range readings are accurately reported. If the range readings are affected, the effect is typically less
than 5 mm. This allows users to employ real-time ultrasonic distance sensing without the need for additional supporting
circuitry or complicated user software.
Many acoustic noise sources will have little to no effect on the reported range of the HRLV-MaxSonar-EZ sensors.
However, users are encouraged to test sensor operation in the operating environment.
Sensor Minimum Distance - No Sensor Dead Zone
The sensor minimum reported distance is 30-cm (11.8 inches). However, the HRLV-MaxSonar-EZ will range and report
targets to within 1-mm of the front sensor face. Large targets closer than 30-cm will typically range as 300-mm.
Sensor Operation from 30-cm to 50-cm
Because of acoustic phase effects in the near field, objects between 30-cm and 50-cm may experience acoustic phase
cancellation of the returning waveform resulting in inaccuracies of up to 5-mm. These effects become less prevalent as the
target distance increases, and has not been observed past 50-cm. For this reason, industrial users that require the highest
sensor accuracy are encouraged to mount the HRLV-MaxSonar-EZ from objects that are farther than 50-cm.
Range “0” Location
The HRLV-MaxSonar-EZ reports the range to distant targets starting from the back of the sensor PCB as shown in the
diagram below.
In general, the HRLV-MaxSonar-EZ will report the range to the leading edge of the closest detectable object. Target
detection has been characterized in the sensor beam patterns.
Target Size Compensation
Most low cost ultrasonic rangefinders will report the range to smaller size targets as farther than the actual distance. In
addition, they may 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, provided an
object is large enough to be detected, the sensor will report the same distance, typically within 2%, regardless of target
size. Smaller targets can have additional detection noise that may limit this feature. In addition, targets with small or
rounded surfaces may have an apparent distance that is slightly farther, where the distance reported may be a composite of
the sensed object(s). Compensation for target size is applied to all range outputs: pulse width, analog voltage, and serial
RS232 or TTL.
MaxBotix
®
Inc.
Copyright 2005 - 2012 MaxBotix Incorporated
Patent 7,679,996
MaxBotix Inc., products are engineered and assembled in the USA
Page 3
Web:
www.maxbotix.com
PD11721d
HRLV-MaxSonar
®
- EZ
™
Series
Supply Voltage Droop and Charge Compensation
During power up, the HRLV-MaxSonar-EZ sensor line will calibrate itself for changes in supply voltage. Additionally,
the sensor will compensate if the supplied voltage gradually changes.
If the voltage applied to the sensor changes faster than 0.5V per second, it is best to remove and reapply power to the
sensor.
The sensor requires noise free power for best operation. If the sensor is used with noise on the supplied power, the
readings may be affected. Typically adding a 100uF capacitor at the sensor between the V+ and GND pins will correct
most power related electrical noise issues.
_______________________________________________________________________________________________________________________________________
HRLV-MaxSonar
®
-EZ
™
Mechanical Dimensions
_______________________________________________________________________________________________________________________________________
HRLV-MaxSonar
®
-EZ™ Temperature Compensation
On Board - Internal Temperature Compensation
The speed of sound in air increases about 0.6 meters per second, per degree centigrade. Because of this, each HRLV-
MaxSonar-EZ is equipped with an internal temperature sensor which allows the sensor to apply a compensation for speed
of sound changes.
The self heating (15mW at 5V, or 8mW at 3.3V) will change the temperature of the sensor by about 1 degree C. The
amount of self heating is dependent upon user mounting.
Most importantly, the actual air temperature of the path between the sensor and the target may not match the temperature
measured at the sensor electronics. Sensors mounted in vertical applications, or applications where the environmental
temperature gradient is severe, may experience a large temperature measurement error which will effect the sensor
accuracy. For example, buildings with a height of 2-meters can have floor to ceiling temperature variations of 5°C or
more. Because of these temperature effects, users desiring the highest accuracy output are encouraged to use a properly
mounted external temperature sensor or to manually account for this measurement error.
HR-MaxTemp
®
External Temperature Sensor
Although the HRLV-MaxSonar-EZ
has an internal temperature sensor; for best accuracy, users are encouraged to use the
optional external temperature sensor. On power-up the HRLV-MaxSonar-EZ will automatically detect an attached
HR-MaxTemp temperature sensor and begin to apply temperature compensation using the external temperature sensor.
The external temperature sensor allows for the most accurate temperature compensation, by eliminating sensor
self-heating from the sensor electronics, and by allowing the user to place the temperature sensor closer to the center of
the acoustic ranging path.
For best results users are encouraged to connect the temperature sensor midway between the HRLV-MaxSonar-EZ and
the expected target distance.
MaxBotix
®
Inc.
Copyright 2005 - 2012 MaxBotix Incorporated
Patent 7,679,996
MaxBotix Inc., products are engineered and assembled in the USA
Page 4
Web:
www.maxbotix.com
PD11721d
HRLV-MaxSonar
®
- EZ
™
Series
HRLV-MaxSonar
®
-EZ
™
Operating Modes
Multiple Sensor Operation
When using multiple ultrasonic sensors in a single system, there can be interference (cross-talk) from other sensors.
MaxBotix Inc., has engineered a solution to this problem for the HRLV-MaxSonar-EZ sensors. The solution is referred to
as chaining. We have 3 methods of chaining that work well to avoid this issue of cross-talk.
The first method is an Analog Voltage Output Commanded Loop. The first sensor will range, then trigger the next sensor
to range and so on for all the sensors in the array. Once the last sensor has ranged, the array stops until the first sensor is
triggered to range again. Below is a diagram on how to set this up.
The next method is Analog Voltage Output Constant Looping. The first sensor will range, then trigger the next sensor to
range and so on for all the sensors in the array. Once the last sensor has ranged, it will trigger the first sensor in the array
to range again. This will cause the array to loop indefinitely, or until the chain is broken. Below is a diagram on how to
set this up.
The final method is Analog Voltage Output Simultaneous Operation. This method does not work in all applications and is
sensitive to how the other sensors in the array are positioned in comparison to each other. Testing is recommended to
verify that this method will work for your application. All sensors RX pins are connected together and are triggered at the
same time causing all the sensors to take a range reading at the same time. Once the range reading is complete, the
sensors stop ranging until they are triggered again. Below is a diagram on how to set this up.
MaxBotix
®
Inc.
Copyright 2005 - 2012 MaxBotix Incorporated
Patent 7,679,996
MaxBotix Inc., products are engineered and assembled in the USA
Page 5
Web:
www.maxbotix.com
PD11721d
Embedded System
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