XL-TrashSonar
™
-WR
™
Series
XL-TrashSonar -WR Series
IP67 Weather Resistant, Ultrasonic Trash Sensor
MB7137, MB7138, MB7139
3
™
™
The XL-TrashSonar-WR sensor series provide users with robust range
information in air. These sensors also feature high-power acoustic output along
with real-time auto calibration for changing conditions (supply voltage sag,
acoustic noise, or electrical noise), operation with supply voltage from 3.0V to
5.5V, object detection from 0-cm to 350-cm, and sonar range information from
20-cm out to 350-cm with 1-cm resolution. Objects from 0-cm to 20-cm typically
range as 20-cm. (
25cm for the MB7138
2
)
The sensor is housed in a robust PVC housing,
designed to meet the IP67 water intrusion standard. This sensor line is available in the following package types
— 3/4” PVC threading, 1” NPS pipe threading, 1” BSPP pipe threading, and 30mm 1.5 pipe threading.
The user interface formats included are pulse-width, analog voltage output, RS232 serial output, and
I2C (MB7137).
Features
•
Real-time auto calibration and noise
rejection
•
High acoustic power output
•
Precise narrow beam
•
Object detection includes zero range
objects
•
3V to 5.5V supply with very low
average current draw
•
Free run operation can continually
measure and output range
information
•
Triggered operation provides the
range reading as desired
•
All interfaces are active
simultaneously
•
RS232 Serial, 0 to Vcc, 9600 Baud,
81N (MB7138, MB7139)
•
I2C Bus operates up to 400KHz with
clock stretching (MB7137)
•
Analog, (Vcc/1024) / cm (MB7138,
MB7139)
•
Sensor operates at 42KHz
Benefits
•
Acoustic and electric noise
resistance
•
Reliable and stable range data
•
Robust, low cost IP67 standard
sensor
•
Narrow beam characteristics
•
Very low power excellent for battery
based systems
•
Ranging can be triggered externally
or internally
•
Sensor reports the range reading
directly, frees up user processor
•
Easy hole mounting or mating with
standard electrical fittings
•
Filtering allows very reliable
operation in most environments
Applications & Uses
•
•
•
•
•
•
•
•
Tank level measurement
Bin level measurement
Trash level measurement
Environments with acoustic and
electrical noise
Distance measuring
Long range object detection
Industrial sensor
-40°C to +65°C operation
1
Notes:
1
Please reference page 15 for minimum operating
voltage verses temperature information.
2
Minimum distance is 25cm for the MB7138
3
Please reference page 20 for part number key.
Close Range Operation
Applications requiring 100% reading-to-reading reliability should not use MaxSonar sensors at a distance closer than
20cm. Although most users find MaxSonar sensors to work reliably from 0 to 20cm for detecting objects in many
applications, MaxBotix
™
Inc. does not guarantee operational reliability for objects closer than the minimum reported
distance. Because of ultrasonic physics, these sensors are unable to achieve 100% reliability at close distances.
25cm for the MB7138
2
_______________________________________________________________________________________________________________________________________
Warning: Personal Safety Applications
We do not recommend or endorse this product be used as a component in any personal safety applications. This product is
not designed, intended or authorized for such use. These sensors and controls do not include the self-checking redundant
circuitry needed for such use. Such unauthorized use may create a failure of the MaxBotix
™
Inc. product which may result
in personal injury or death. MaxBotix
™
Inc. will not be held liable for unauthorized use of this component.
MaxBotix
®
Inc.
Copyright 2005 - 2015 MaxBotix Incorporated
Patent 7,679,996
MaxBotix Inc., products are engineered and assembled in the USA
Page 1
Web:
www.maxbotix.com
PD13516f
XL-TrashSonar
™
-WR
™
Series
MB7137 Pinout
For I2C informa on please skip to page 12
Pin 1 - Temporary Default:
This pin is internally pulled high. On power up, the state of this pin is checked. If the pin is
left high or disconnected the sensor will use the address stored in memory for I2C communication. If pulled low, the
sensor will use its default address for the current power cycle.
Pin 2 - Address Announce / Status:
While the sensor is performing a range reading. During non-ranging operation, this
pin is held low and the sensor is listening for incoming I2C communication. Operationally, users may poll this pin to
determine if the sensor has finished its ranging cycle and is ready to report the latest range information.
During power-up this pin will provide a pulse width representation of the sensor’s current address with a length of ~100
microseconds per digit. (The default address of 224 will announce with a pulse of 22,400 microseconds in length)
Pin 3 - Not Used:
This pin is not used.
Pin 4 - SDA (I2C Data):
This is the data line for I2C communications. These sensors operate as I2C slave devices.
Pin 5 - SCL (I2C Clock):
This is the clock line for I2C communications. These sensors support I2C clock frequencies up
to 400KHz provided clock stretching is supported by the master devices. Without clock stretching the devices can run at
speeds up to 50KHz.
V+
Operates on 3V - 5.5V. The average (and peak) current draw for 3.3V operation is 2.7mA (50mA peak) and 5V
operation is 4.4mA (100mA peak) respectively. Peak current is used during sonar pulse transmit. Please reference page 15
for minimum operating voltage verses temperature information.
GND:
Return for the DC power supply. GND (& V+) must be ripple and noise free for best operation.
_______________________________________________________________________________________________________________________________________
MB7138 & MB7139 Pinout
Pin 1 - BW:
Leave open (or high) for serial output on the Pin 5 output. When Pin 1 is held low the Pin 5 output sends a
pulse (instead of serial data), suitable for low noise chaining.
Pin 2 - PW:
This pin outputs a pulse-width representation of range. To calculate the distance, use a scale factor of 58uS
per cm.
Pin 3 - AN:
This pin outputs analog voltage with a scaling factor of (Vcc/1024) per cm. A supply of 5V yields ~4.9mV/
cm., and 3.3V yields ~3.2mV/cm. The output is buffered and corresponds to the most recent range data.
Pin 4 - RX:
This pin is internally pulled high. If Pin-4 is left unconnected or held high, the sensor will continually
measure the range. If Pin-4 is held low the sensor will stop ranging. Bring high 20uS or more to command a range
reading.
Pin 5 - TX:
When Pin 1 is open or held high, the Pin 5 output delivers asynchronous serial data in an RS232 format,
except the voltages are 0-Vcc. The output is an ASCII capital “R”, followed by ASCII character digits representing the
range in centimeters up to a maximum of 350, followed by a carriage return (ASCII 13). The baud rate is 9600, 8 bits, no
parity, with one stop bit. Although the voltages of 0V to Vcc are outside the RS232 standard, most RS232 devices have
sufficient margin to read the 0V to Vcc serial data. If standard voltage level RS232 is desired, invert, and connect an
RS232 converter such as a MAX232.When Pin 1 is held low, the Pin 5 output sends a single pulse, suitable for low noise
chaining (no serial data).
V+
Operates on 3V - 5.5V. The average (and peak) current draw for 3.3V operation is 2.1mA (50mA peak) and 5V
operation is 3.4mA (100mA peak) respectively. Peak current is used during sonar pulse transmit. Please reference page 15
for minimum operating voltage verses temperature information.
GND-Return
for the DC power supply. GND (& V+) must be ripple and noise free for best operation.
_______________________________________________________________________________________________________________________________________
About Ultrasonic Sensors
Our ultrasonic sensors are designed for use in air, non-contact object detection and ranging sensors that detect objects
within a defined 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 - 2015 MaxBotix Incorporated
Patent 7,679,996
MaxBotix Inc., products are engineered and assembled in the USA
Page 2
Web:
www.maxbotix.com
PD13516f
XL-TrashSonar
™
-WR
™
Series
Supply Voltage Compensation
During power up, the XL-TrashSonar-WR sensor line will calibrate itself for the supply voltage. Additionally, the sensor
will compensate if the supplied voltage gradually changes.
If the average voltage applied to the sensor changes faster than 0.5V per second, it is best to remove and reapply power to
the sensor.
For best operation, the sensor requires noise free power. If the sensor is used with noise on the supplied power or ground,
the accuracy of 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.
_______________________________________________________________________________________________________________________________________
MB7139
The MB7139 is the base model of the XL-TrashSonar-WR sensor line. This sensor is recommended for general purpose
use. The additional features are mentioned below.
The MB7139 reports the range to the first detectable target. Unless the target is barely detectable, this sensor will have a
very stable output. If a smaller object is in front of the target, the sensor may report the range to the object depending on
the object’s size and position.
_______________________________________________________________________________________________________________________________________
MB7137
The MB7137 communicates using the I2C bus protocol. This sensor reports the range to the first detectable target in
real-time. This sensor is capable of outputting new range readings with speeds up to 40Hz if the status pin is being
monitored. The recommended refresh rate is 10Hz or slower.
_______________________________________________________________________________________________________________________________________
MB7138
The XL-TrashSonar-WRM sensors prioritize large targets over both small targets and noise. These sensors report the
target that gives the largest acoustic reflection. This stands in contrast to other units such as the MB7139 which are
designed to report the distance to the first detectable target. If the largest target is removed from the field of view, the
MB7138 will switch to the target that gives the next largest detectable return.
25cm for the MB7138
2
The XL-TrashSonar-WRM sensors are designed for applications where users are concerned with ranging the distance to
flat targets (such as water and fuel tanks).
When targets are of similar amplitude reflections, preference is given to the closer target. The sensor expects to see a
target by 3.5 meters. If no target is found, the sensor will increase in sensitivity until a target is found, or until no targets
can be found.
In addition to the most-likely filtering, the MB7052 and MB7092 come equipped with a three-reading filter and reading
hold which requires three consecutive range readings within 1cm of the most recent reading to be considered a valid range
reading. If readings are found to be outside 1cm, or no target can be found by the sensor, then the sensor will report the
last valid range reading. Upon power-up the sensor will default to reporting 3.5 meters unit a valid range reading is found.
The last reading hold is designed for users operating in environments with intermittent high noise who desire to poll the
MB7138 at intermittent times. This allows the sensor to report the previously valid reading until the sensor’s environment
improves. If no valid range reading is found for ~1.5 hours, the sensor will send a fail-safe output “000” on all interfaces.
MaxBotix
®
Inc.
Copyright 2005 - 2015 MaxBotix Incorporated
Patent 7,679,996
MaxBotix Inc., products are engineered and assembled in the USA
Page 3
Web:
www.maxbotix.com
PD13516f
XL-TrashSonar
™
-WR
™
Series
Sensor Integration
The XL-TrashSonar-WR sensors are designed to be mounted at the top of a trash receptacle near the center. For best
operation, it is recommended that end users conduct filtering of the sensor data to achieve the most reliable results.
Filtering Examples
•
History Filter — Verifies the reading is accurate when compared to the previous ranges.
•
Mode Filter — Output the sensor’s reported range that is shown the most.
•
Median filter — Output the reported range that is in the center of a range set.
Sensor Mounting
Trash bins that are lined with plastic bags may detect false reflections if there is air trapped behind the plastic bag.
If the sensor is mounted in a trash bin with stepping sides that get narrower from top down, shown in Diagram 1, the
sensor will typically not range properly to the trash. In this installation the sensor may report the range to the highest side
step.
For trash bins with internal side braces, shown in Diagram 2, the sensor will not report the range past the internal brace.
Like the side steps, this brace creates an ultrasonic echo that the sensor may report the range to.
For installations with that get wider from the top of the bin to the base, shown in Diagram 3, the sensor will typically
report the trash level properly. Testing is recommended for this configuration if side steps get dramatically wider as they
may be detected by the XL-TrashSonar-WR.
Diagram 4 shows the ideal sensor mounting for the XL-TrashSonar-WR sensor line. It is recommended that the sensor is
mounted in a trash bin with smooth sides. This either eliminates or dramatically reduces the secondary reflections that
may return to the sensor.
Diagram 1
Diagram 2
Diagram 3
Diagram 4
1ft
min.
2in
max.
In both of these configurations
the sensor will range to the first
indentation in the trash bin. The
indentation creates a large
detectable reflection.
This configuration
typically operates
properly.
In this configuration
the sensor typically
operates properly. This
is the recommended
mounting method.
As the bin increases in size, the less likely the installation is going to detect unwanted objects and noise.
Testing is recommended for any sensor mounting method and bin size.
MaxBotix
®
Inc.
Copyright 2005 - 2015 MaxBotix Incorporated
Patent 7,679,996
MaxBotix Inc., products are engineered and assembled in the USA
Page 4
Web:
www.maxbotix.com
PD13516f
XL-TrashSonar
™
-WR
™
Series
Sensor Minimum Distance
The XL-TrashSonar-WR sensors have a minimum reported distance of 20-cm (7.87 inches). However, the
XL-TrashSonar-WR will range and report targets to the front sensor face. Large targets closer than 20-cm will typically
range as 20-cm. For the alternative housings, objects between 4-cm and 20-cm will typically range as 20-cm.
_______________________________________________________________________________________________________________________________________
About Package Types
The XL-TrashSonar-WR sensor line is available in a variety of packages for applications with specific mounting
requirements. The full horn package provides peak accuracy and sensitivity in this sensor line. It is recommended that
testing is completed to ensure that the selected sensor will operate as desired in your application.
Package Types Currently Available
Full Horn — 3/4” NPT straight; back mounted thread (best performance)
Compact — 3/4” NPT straight; back mounted thread
Ultra-Compact — PCB with 4 moun ng holes
1”NPS — External thread over full sensor body (1”NPS)
1” BSPP — External thread over full sensor body (1”BSPP)
30mm1.5 — External thread over full sensor body (30mm1.5)
All package types have exposed PCB on user end for easy connec on.
Users desiring a fully enclosed assembly may purchase the “Shielded
Cable A ach Op on” along with their sensor.
Performance Changes when Selecting a Non-Full Horn Package
When selecting a XL-TrashSonar-WR without the full horn the sensor will experience the following performance
changes:
•
The sensor will have a wider beam shape for the first meter.
•
The sensor may have a dead zone from 0-6cm.
•
The sensor may have worse performance to small or soft targets.
•
The sensor may experience decreased noise immunity when ranging to small, soft, angled, or distant targets.
_______________________________________________________________________________________________________________________________________
Mechanical Dimensions
Full Horn
A
1.72”
dia.
43.8 mm
dia.
2.00”
50.7 mm
B
0.58”
14.4 mm
C
0.31”
7.9 mm
D
0.23”
5.8 mm
E
0.10”
2.54 mm
F
3/4”-14 NPS
G
H
1.032”
dia.
26.2 mm
dia.
1.37”
34.8 mm
I
Weight
50 grams
Values Are Nominal
C
D
E
Pin 1
B
A
F
G
H
I
MaxBotix
®
Inc.
Copyright 2005 - 2015 MaxBotix Incorporated
Patent 7,679,996
MaxBotix Inc., products are engineered and assembled in the USA
Page 5
Web:
www.maxbotix.com
PD13516f
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