Scanse SWEEP V1.0 User manual

Cost efficient design
Operates in full sunlight
Low power consumption
Wide field of view
Small footprint
Simple serial connectivity
Long Range
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.
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
Date
Changes
0.9
12/19/2016
Initial Release
0.91
01/05/2016
Added MS, LR, LI Packets
0.92
01/06/2017
Added power safety text
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
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
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
CAUTION
sweep v1.0

SPECIFICATIONS USER’S MANUAL SWEEP V1.0
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Copyright ©2014-2017 Scanse LLC - www.scanse.io
ALL DIMENSIONS ARE IN MM, DRAWINGS ARE NOT TO SCALE
Figure 1, Sweep Dimension Drawing
Specification
Value
Weight
120 g (4.23 oz.)
Operating Temperature
-10 to 60° C (14 to 140°F)
Storage Temperature
-40 to 80° C (-40 to 176°F)
Specification
Value
Power
5VDC ±0.5Vdc
Current Consumption
Up to 650mA
450mA nominal
Specification
Value
Range
(75% reflective target)
40 m (131ft)
Resolution
1 cm (0.4 in)
Update Rate
(75% reflective target)
Up to 1075Hz (see
“Theory of Operation”)
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
Figure 3, Sweep Accuracy Graphs
0
10
20
30
0%
5%
10%
15%
20%
25%
30%
0 1000 2000 3000 4000
±cm Measurement Variability
% Error
Range in Centimeters
Long Range Error With 75% Reflective Target
0
10
20
30
0%
5%
10%
15%
20%
25%
30%
0100 200 300 400 500
±cm Measurement Variability
% Error
Range in Centimeters
Close Range Error With 75% Reflective Target
Specification
Value
Horizontal Field of View
360 degrees
Vertical Field of View
0.5 degrees

SPECIFICATIONS USER’S MANUAL SWEEP V1.0
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Copyright ©2014-2017 Scanse LLC - www.scanse.io
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 4, Sweep Cable Diagram
Sweep has two serial port connectors with identical
signals. This allows for more mounting options.
Figure 5, Sweep Pigtail Cable Connector Detail
Pin
Color
Function
1
Red
5 Vdc (+) (minimum 0.5A capable)
2
Orange
Power enable (internal pull-up)
3
Yellow
Sync/Device Ready
4
Green
UART RX 3.3V (5V compatible)
5
Blue
UART TX 3.3V (5V compatible)
6
Black
Ground (-)
You can create your own cable if needed for your
application. These components are readily available.
Part
Description
Mfg.
Part No.
Connector
Housing
6-Position,
rectangular
housing, latch-
lock connector
receptacle with
1.25 mm
(0.049 in.) pitch.
JST
GHR-06V-S
Connector
terminal
26-30 AWG crimp
socket connector
JST
SSHL-002T-
P0.2
Wire
UL 1061 26 AWG
stranded copper
N/A
N/A
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

SPECIFICATIONS USER’S MANUAL SWEEP V1.0
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Copyright ©2014-2017 Scanse LLC - www.scanse.io
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.

SERIAL PROTOCOL USER’S MANUAL SWEEP V1.0
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Copyright ©2014-2017 Scanse LLC - www.scanse.io
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
Value
Bit Rate
115.2 Kbps
Parity
None
Data Bit
8
Stop Bit
1
Flow Control
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)
Function
DS
Start data acquisition
DX
Stop data acquisition
MS
Adjust Motor Speed
LR
Adjust LiDAR Sample Rate
MI
Motor Information
IV
Version Info
ID
Device Info
RR
Reset Device

SERIAL PROTOCOL USER’S MANUAL SWEEP V1.0
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Copyright ©2014-2017 Scanse LLC - www.scanse.io
(HOST -> SENSOR)
Command with no parameter
Command Symbol
(2 bytes)
Line Feed
(LF)
Example: DS, DX, MS, MI, IV…
Line Feed (LF) or Carriage Return (CR)
or
Command with parameter
Command Symbol
(2 bytes)
Parameter
(2 bytes)
Line Feed
(LF)
(SENSOR -> HOST)
Response with no parameter echoed
Command Symbol
(2 bytes)
Status
(2 bytes)
Sum of Status
Line Feed
(LF)
or
Command with parameter echoed
Command Symbol
(2 bytes)
Parameter
(2 bytes)
Line Feed
(LF)
Status
(2 bytes)
Sum of Status
Line Feed
(LF)
Command Symbol: 2 byte code at the beginning of every command.
Parameter: Information that is needed to change sensor settings.
Line Feed (LF) or Carriage Return (CR): Terminating code. Command can have LF or CR or both as termination
code but reply will always have LF as its termination code.
Status: 2 bytes of data in reply that informs normal processing if command is authenticated or errors if undefined,
invalid or incomplete command is received by sensor. Status other than 00 and 99 are error codes.
Sum of Status: 1 byte of data used in authentication. Calculated by adding status bytes, taking lower 6 byte of this
sum and adding 30H to this sum.
Sum = 111111 = 3fH+30H = 6fH = o
Example: [LF] 0 0 [LF] = P
Responses to Invalid Commands: 11 -- Invalid parameter
Initiates scanning
Responds with header containing status.
Next responds with measurement packets indefinitely until commanded to stop.
(HOST -> SENSOR)
D
S
LF
(SENSOR -> HOST)
Header response
D
S
Status
(2 bytes)
SUM
(2 bytes)
LF
Data Block (7 bytes) Data Block
Sync/Error
(1 byte)
Azimuth - degrees(float)
(2 bytes)
Distance - cm(int)
(2 bytes)
Signal Strength (1
byte)
Checksum
(1 byte)

SERIAL PROTOCOL USER’S MANUAL SWEEP V1.0
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Copyright ©2014-2017 Scanse LLC - www.scanse.io
sync bit : 0 bit indicates the sync value, a value of 1 indicates the packet is the beginning of a new scan, a value of 0
indicates all other measurement packets. Bits 1-6 are reserved for error codes, see below.
error code bits : 1st bit indicates whether or not there was a communication error with the LiDAR Module. A value
of 1 indicates that there was an error, and a value of 0 indicates there was no error.
bits 2-7 reserved for future use.
azimuth: Angle that ranging was recorded at. Azimuth is a float value - needs to be converted from 16bit int to
float, use instructions at the top
distance: Distance of range measurement.
signal strength: Signal strength of current ranging measurement. Larger is better. Range: 0-255
checksum: Calculated by adding the 6 bytes of data then dividing by 255 and keeping the remainder. (Sum of bytes
0-6) % 255
Status
00 -- Command received without any Error
22 -- Stopped to verify error
55 -- Hardware trouble
99 -- Resuming operation
Stops outputting measurement data.
(HOST -> SENSOR)
D
X
LF
(SENSOR -> HOST)
D
X
Status
SUM
LF
Default Speed: Sensor stores last speed command in non-volatile memory, and will return to that speed after a
power cycle, except if the last state was speed 00 (stopped).
(HOST -> SENSOR)
M
S
Speed Parameter
(2 bytes)
LF
Speed Parameter: 00 - 10 : 10 different speed levels according to revolutions per second (Hz), increments of 1.
Example: 01,02,..
00 = Motor stopped
(SENSOR -> HOST)
M
S
Speed(Hz)
(2 bytes)
LF
Status
Sum
LF

SERIAL PROTOCOL USER’S MANUAL SWEEP V1.0
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Copyright ©2014-2017 Scanse LLC - www.scanse.io
Default Speed: 5Hz
Once a speed is set, the sensor will always return to this speed, even after a power cycle (except when setting the
speed to 0Hz –in which case it will go back to 5Hz after a power cycle).
(HOST -> SENSOR)
M
S
Speed Parameter
(2 bytes)
LF
Speed Parameter: 00 - 10 : 10 different speed levels according to Hz, increments of 1. ie: 01,02,..
00 = Motor stopped.
(SENSOR -> HOST)
M
S
Speed(Hz)
(2 bytes)
LF
Status
Sum
LF
Default Sample Rate: 500-600Hz. See Theory of Operation section for explanation of why there is arrange of
sample rate values.
(HOST -> SENSOR)
L
R
Speed Parameter
(2 bytes)
LF
Sample Rate Parameter Code:
01 = 500-600Hz
02 = 750-800Hz
03 = 1000-1075Hz
(SENSOR -> HOST)
L
R
Speed(Hz)
(2 bytes)
LF
Status
Sum
LF
Returns current LiDAR Sample Rate Code
01 = 500-600Hz
02 = 750-800Hz
03 = 1000-1050Hz
(HOST -> SENSOR)
L
I
LF
(SENSOR -> HOST)
L
I
Speed(Hz)
(2 bytes)
LF
Returns current rotation frequency in Hz in ASCII 00 - 10 (increments of 1)
(HOST -> SENSOR)
M
I
LF
(SENSOR -> HOST)
M
I
Speed(Hz)
(2 bytes)
LF

SERIAL PROTOCOL USER’S MANUAL SWEEP V1.0
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Copyright ©2014-2017 Scanse LLC - www.scanse.io
Model
Protocol Version
Firmware Version
Hardware Version
Serial Number
(HOST -> SENSOR)
I
V
LF
(SENSOR -> HOST)
I
V
Model
(5 bytes)
Protocol
(2 bytes)
Firmware Version
(2 bytes)
Hardware Version
(1 byte)
Serial Number
(8 bytes)
LF
Example: IVSWEEP01011100000001
I
V
SWEEP
01
01
1
00000001
LF
Bit Rate
Laser State
Mode
Diagnostic
Motor Speed
Sample Rate
(HOST -> SENSOR)
I
D
LF
(SENSOR -> HOST)
I
D
Bit Rate
(6 bytes)
Laser state
Mode
Diagnostic
Motor Speed
(2 bytes)
Sample Rate
(4 bytes)
LF
Example: IV115200110050500
I
D
115200
1
1
0
05
0500
LF
Reset Scanner
(HOST -> SENSOR)
R
R
LF
(SENSOR -> HOST)
No Response