Laser Safety .......................................................0
Power Safety .....................................................0
Specifications ..................................................... 1
Physical .............................................................1
Electrical ............................................................1
Measurement Performance ..............................1
Field of View .....................................................1
Measurement Error Test Data ..........................1
Overview of Interfaces ....................................... 2
Connector .........................................................2
Mounting and Vibration Considerations ............ 2
Mounting Features and Orientation .................3
Ingress Protection Rating ..................................3
Enclosure Window Design ................................3
sweep
v1.0
Theory of Operation ........................................... 3
Distance Measurement .....................................3
Angle Measurement .........................................3
Applications ....................................................... 4
Internal Filters .................................................... 4
Visualizer Overview ............................................ 4
Serial Protocol Specification ............................... 4
Data Encoding and Decoding ............................4
Communication Format ....................................4
Available Command Codes ................................. 4
General Communication Packet Structure.......... 5
Definition of terms: ...........................................5
This device contains a component which emits laser radiation. The
laser product is designated Class 1 during all operating modes.
This means that the laser is safe to look at with the unaided eye,
however it is advisable to not look directly into the beam when in
use.
Cost efficient design
Operates in full sunlight
Low power consumption
Wide field of view
Small footprint
Simple serial connectivity
Long Range
CAUTION
DS - Start data acquisition .................................5
DX - Stop data acquisition .................................6
MS - Adjust Motor Speed ..................................6
MS
–
Adjust Motor Speed .................................7
LR
–
Adjust LiDAR Sample Rate .........................7
LI
–
LiDAR Information ......................................7
MI
–
Motor Information ....................................7
IV - Version Details ............................................8
ID - Device Info ..................................................8
RR - Reset Device ..............................................8
When connecting a Sweep sensor to a 5VDC power source, it
should be limited to a maximum of 8A as defined in EN 60950-1,
sub clause 2.5, Table 2B.
Documentation Revision Information
Rev
0.9
0.91
0.92
Date
12/19/2016
01/05/2016
01/06/2017
Changes
Initial Release
Added MS, LR, LI Packets
Added power safety text
SPECIFICATIONS
USER’S MANUAL
SWEEP
V1.0
Specification
Horizontal Field of View
Vertical Field of View
Value
360 degrees
0.5 degrees
Sweep is a single plane scanner. This means that as
its head rotates
counterclockwise,
it records data in
a single plane. The beam starts out at approximately
12.7mm in diameter and expands by approximately
0.5 degrees as show in Figure 2.
Figure 2, Sweep Field of View
Long Range Error With 75% Reflective Target
25%
Figure 1, Sweep Dimension Drawing
% Error
ALL DIMENSIONS ARE IN MM, DRAWINGS ARE NOT TO SCALE
20%
15%
10%
5%
0%
0
1000
2000
3000
Range in Centimeters
20
10
0
4000
Specification
Weight
Operating Temperature
Storage Temperature
Value
120 g (4.23 oz.)
-10
to 60° C (14 to 140°F)
-40 to 80° C (-40 to 176°F)
Close Range Error With 75% Reflective Target
±
cm Measurement Variability
Specification
Power
Current Consumption
% Error
Value
5VDC ±0.5Vdc
Up to 650mA
450mA nominal
30%
25%
20%
15%
10%
5%
0%
30
20
10
Specification
Range
(75% reflective target)
Resolution
Update Rate
(75% reflective target)
Value
40 m (131ft)
1 cm (0.4 in)
Up to 1075Hz (see
“Theory of Operation”)
0
0
100
200
300
400
500
Range in Centimeters
Figure 3, Sweep Accuracy Graphs
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Copyright ©2014-2017 Scanse LLC - www.scanse.io
±
cm Measurement Variability
30%
30
SPECIFICATIONS
USER’S MANUAL
SWEEP
V1.0
Sweep can be connected to low level micro
controllers directly using its serial port, or to a PC
using the provided USB to serial converter.
Figure 5, Sweep Pigtail Cable Connector Detail
Figure 4, Sweep Cable Diagram
Sweep has two serial port connectors with identical
signals. This allows for more mounting options.
Pin
1
2
3
4
5
6
Color
Red
Orange
Yellow
Green
Blue
Black
Function
5 Vdc (+) (minimum 0.5A capable)
Power enable (internal pull-up)
Sync/Device Ready
UART RX 3.3V (5V compatible)
UART TX 3.3V (5V compatible)
Ground (-)
You can create your own cable if needed for your
application. These components are readily available.
Part
Connector
Housing
Description
6-Position,
rectangular
housing, latch-
lock connector
receptacle with
1.25 mm
(0.049 in.) pitch.
26-30 AWG crimp
socket connector
UL 1061 26 AWG
stranded copper
Mfg. Part No.
JST GHR-06V-S
Connector
terminal
Wire
SSHL-002T-
P0.2
N/A N/A
JST
Sweep can be mounted in any orientation.
Sweep’s
rotating head is dynamically balanced, which means
it is immune to linear vibration, but it can be
affected by rotational vibration. Sudden rotational
shocks can cause the head to either slow down or
speed up, which can affect data accuracy. If Sweep is
rotationally jerked hard enough, it can cause the
motor to lose sync, which will trigger a momentary
motor pause, and then restart.
DRAWINGS ARE NOT TO SCALE
Figure 6, Sweep Connector Diagram
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Copyright ©2014-2017 Scanse LLC - www.scanse.io
SPECIFICATIONS
USER’S MANUAL
SWEEP
V1.0
Sweep has four brass threaded inserts designed to fit
M2.5X0.45 screws in its base. These are the best
features for mounting Sweep to an application. The
screw holes are aligned with the scanner’s
measurement angles. The scanner’s zero
degree
starting angle is aligned with the status LED, as
shown in Figure 7.
Sweep is rated as IP51, which is to say, it is not dust
or water tight. It is recommended that Sweep be
placed inside a protective transparent enclosure if it
will be used in dusty or wet environments.
Figure 7, Sweep Mounting Features (all dimensions in mm)
Sweep uses 905nm laser light, which passes through several kinds of clear glass and plastic very well. Based on our
testing, clear Polycarbonate plastic is one of the best choices, as it can be molded to fit the profile of the
application’s enclosure, is very inexpensive, and in most
cases, is more than 95% translucent to Sweep’s
light
beam. Factors that can affect the performance of a window are:
Thickness of the window. Thicker windows will block more light, as well as bend the light more if the beam is
not hitting the window normal to the surface.
Scratches and dust. The presence of scratches and dust on the window will scatter the laser light, and may
reflect some of the light back into the sensor’s detector, causing measurement errors.
Surface coatings. There are a variety of coatings that can help with the performance of windows. One is an
anti-reflective (AR) coating, which can help reduce the amount of laser light that is reflected as it passes
through the window’s surface.
Sweep employs a time of flight ranging method. This technique involves transmitting a packet of micro pulses of
light in a unique pattern. When this light bounces off an object and returns to the receiving detector, a correlation
algorithm is used to identify the unique light pattern from ambient noise.
Each light packet is different from the
last, which allows multiple Sweep sensors to operate adjacent to each other without interference.
The light packets that Sweep uses can vary in length, which can affect accuracy of range measurements, as well as
the maximum range and update rate. Under normal operation, Sweep limits the maximum time per measurement
to a value determined by the sample rate set using the
LR
command (see LR packet structure description). If not
enough light is returned from the environment, the measurement fails, and a 1 is returned as the range value. On
the other hand, if allot of light is returned from the environment, the correlation algorithm can reach its maximum
accuracy early, and can return a range value more quickly. This is what makes the update rate of Sweep variable.
The value of setting a slower sample rate using the
LR
command, is that more light will be gathered from a target,
and the range measurements will be more accurate. The exact accuracy is determined by many factors, including
the target surface characteristics and ambient noise, so we cannot give an exact number for relative accuracy
between the different
LR
settings.
Sweep uses an optical encoder to measure the angle of the rotating sensor head. The angle that is recorded for a
range data point is the angle the sensor is at when the measurement is completed.
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Copyright ©2014-2017 Scanse LLC - www.scanse.io
SERIAL PROTOCOL
USER’S MANUAL
SWEEP
V1.0
Sweep can be used for a variety of applications, including robot guidance/obstacle avoidance, 3D scanning,
surveying, people tracking and many more.
Sweep has the ability to perform some simple data filtering within the sensor itself. These filters are still in
development, and are being made for specific customer segments. Examples include having Sweep split up its field
of view into eight sections, then transmit only the closest objects within each of those sectors. Another example is
to have Sweep only output data from a range of angles.
If you have an application that requires a specific filter,
please contact us.
You can download the Sweep visualizer at
www.scanse.io/downloads
The purpose of the Scanse visualizer is to provide a way to quickly evaluate Sweep’s performance in your
application/environment. For some applications, like surveying, our visualizer can be used to take quick
measurements between range data points within a scan. It
contains a programming tool for updating Sweep’s
firmware.
A full tutorial for using the visualizer can be found in software support section at
support.scanse.io.
Specification
Bit Rate
Parity
Data Bit
Stop Bit
Flow Control
Value
115.2 Kbps
None
8
1
None
All characters used for commands and responses are ASCII code in addition to CR and LF, except for the
measurement packet.
Responses with float values are sent as 16bit integer values.
Example conversion:
angle_f = 1.0f * ((float)(angle_i >> 4) + ((angle_i & 15) / 16.0f));
All communication packets between the host computer and the sensor begin with ASCII letter command codes.
ASCII Code (2 bytes)
DS
DX
MS
LR
MI
IV
ID
RR
Function
Start data acquisition
Stop data acquisition
Adjust Motor Speed
Adjust LiDAR Sample Rate
Motor Information
Version Info
Device Info
Reset Device
4
Copyright ©2014-2017 Scanse LLC - www.scanse.io
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