NXP Semiconductors SLN-VIZNAS-IOT User manual

1 SLN-VIZNAS-IOT User Guide, Rev. 1.1, 10/2020 NXP Semiconductors
MCU VIZNAS Solution User’s Guide
TABLE OF CONTENTS
1INTRODUCTION ............................................................................................................................................ 6
1.1 RT106F VISION CROSSOVER PROCESSOR OVERVIEW ......................................................................................6
1.2 ADDITIONAL PERIPHERALS......................................................................................................................................7
2GET STARTED WITH SLN-VIZNAS-IOT ............................................................................................................9
2.1 BOX CONTENTS....................................................................................................................................................9
2.2 RUNNING THE DEMO ............................................................................................................................................9
2.2.1 Access the Camera...............................................................................................................................10
2.2.2 Register a Face.....................................................................................................................................12
2.2.3 Liveness Detection and Anti-Spoofing..................................................................................................14
2.2.4 Connect to Serial CLI ............................................................................................................................16
2.2.5 Enable Verbose Mode ..........................................................................................................................18
2.2.6 (Optional) Enable Low Power Mode ....................................................................................................20
3ADDITIONAL FEATURES .............................................................................................................................. 22
3.1 PUSH BUTTONS..................................................................................................................................................22
3.1.1 SW1 –Toggle GUI ................................................................................................................................23
3.1.2 SW2 –Manual Deregistration..............................................................................................................24
3.1.3 SW3 –Toggle IR/RGB Output ..............................................................................................................26
3.1.4 SW4 –Manual Registration .................................................................................................................27
3.2SERIAL COMMANDS............................................................................................................................................29
3.2.1 List Available Commands .....................................................................................................................29
3.2.2 List All Registered Users .......................................................................................................................31
3.2.3 Manually Add Users .............................................................................................................................31
3.2.4 Manually Delete Users .........................................................................................................................32
3.2.5 Rename Users ......................................................................................................................................32
3.2.6 Verbose Mode......................................................................................................................................32
3.2.7 Configure IR LED Brightness.................................................................................................................35
3.2.8 Configure White LED Brightness ..........................................................................................................35
3.2.9 Print Version Information ....................................................................................................................35
3.2.10 Save Users Through Resets .............................................................................................................36
3.2.11 Enable OTW (Over-the-Wire) Update Mode ...................................................................................36
3.2.12 Reset the SLN-VIZNAS-IOT...............................................................................................................36
3.2.13 Configure Emotion Recognition ......................................................................................................37
3.2.14 Configure Liveness Detection ..........................................................................................................38
NXPSemiconductors
Document Number: SLN-VIZNAS-IOT-UG
User's Guide
Rev.
1.1,
10/2020

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3.2.15 Configure Detection Resolution.......................................................................................................39
3.2.16 Display IR Output ............................................................................................................................40
3.2.17 Configure Display Output Device (Requires Riverdi Display)...........................................................41
3.2.18 Toggle GUI.......................................................................................................................................41
3.2.19 Toggle Wi-Fi Enablement ................................................................................................................42
3.2.20 Reset Wi-Fi ......................................................................................................................................43
3.2.21 Retrieve Wi-Fi Credentials ...............................................................................................................43
3.2.22 Configure Wi-Fi Credentials.............................................................................................................43
3.2.23 Retrieve IP Address..........................................................................................................................44
3.2.24 Erase Wi-Fi Credentials ...................................................................................................................44
3.2.25 Configure Application Type .............................................................................................................44
3.2.26 Configure Low Power Mode ............................................................................................................45
3.3 REMOTE (WIRELESS)REGISTRATION ......................................................................................................................45
3.3.1 Select Wireless Configuration ..............................................................................................................45
3.3.2 Connect Kits .........................................................................................................................................46
3.3.3 Manage Users......................................................................................................................................48
3.4 REMOTE CREDENTIAL PROVISIONING .....................................................................................................................51
3.5 APP CONFIGURATIONS ........................................................................................................................................52
3.5.1 Light vs. Heavy .....................................................................................................................................52
3.5.2 E-Lock vs. Door Access vs. UserID ........................................................................................................53
3.6 LOW POWER MODE ...........................................................................................................................................54
3.7 AUDIO FEEDBACK...............................................................................................................................................55
3.8 DISPLAY CONFIGURATIONS...................................................................................................................................56
4TROUBLESHOOTING ................................................................................................................................... 58
4.1 REGISTERING A FACE...........................................................................................................................................58
4.1.1 Turn off Liveness Detection..................................................................................................................58
4.1.2 Change App Type .................................................................................................................................58
4.1.3 Debug Using Verbose Mode.................................................................................................................58
4.1.4 Ensure Lighting is Sufficient .................................................................................................................59
4.1.5 Adjust Face Proximity and Position......................................................................................................60
5DOCUMENT DETAILS................................................................................................................................... 62
5.1 REFERENCES......................................................................................................................................................62
5.2 ACRONYMS,ABBREVIATIONS,&DEFINITIONS..........................................................................................................62
5.3 REVISION HISTORY..............................................................................................................................................63
TABLE OF FIGURES
FIGURE 1: SLN-VIZNAS-IOT ADDITIONAL PERIPHERALS...........................................................................................................7
FIGURE 2: DUAL CAMERA ADAPTER KIT CONFIGURATION...........................................................................................................7
FIGURE 3: SLN-VIZNAS-IOT BOX CONTENTS.........................................................................................................................9
FIGURE 4: PLUGGING IN SLN-VIZNAS-IOT KIT .......................................................................................................................9
FIGURE 5: WINDOWS CAMERA APP .....................................................................................................................................10
FIGURE 6: SLN-VIZNAS-IOT CAMERA OUTPUT IN CAMERA APP..............................................................................................11
FIGURE 7: CHANGE CAMERA BUTTON IN WINDOWS CAMERA APP.............................................................................................11
FIGURE 8: SLN-VIZNAS-IOT MANUAL REGISTRATION BUTTON...............................................................................................12
FIGURE 9: REGISTRATION IN PROGRESS.................................................................................................................................12
FIGURE 10: SUCCESSFUL REGISTRATION................................................................................................................................13
FIGURE 11: REGISTRATION FAILED.......................................................................................................................................13

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FIGURE 12: "WELCOME HOME"MESSAGE ...........................................................................................................................14
FIGURE 13: PHONE DISPLAY SPOOF ATTACK..........................................................................................................................14
FIGURE 14: PRINTED PICTURE SPOOF ATTACK........................................................................................................................15
FIGURE 15: FAKE FACE DETECTED .......................................................................................................................................15
FIGURE 16: SERIAL CONNECTION SETTINGS ...........................................................................................................................16
FIGURE 17: SERIAL COMMANDS "HELP"MENU .....................................................................................................................17
FIGURE 18: "VERBOSE 0"...................................................................................................................................................18
FIGURE 19: EXAMPLE VERBOSE MODE DEBUG MESSAGE.........................................................................................................18
FIGURE 20: ON-SCREEN INFO FOR REGISTERING FACE .............................................................................................................19
FIGURE 21: ON-SCREEN INFO FOR RECOGNIZED FACE..............................................................................................................20
FIGURE 22: "RECOGNITION TIMEOUT"MESSAGE ...................................................................................................................21
FIGURE 23: HIBERNATION WAKE-UP TRIGGER (SW3).............................................................................................................21
FIGURE 24: SW1 .............................................................................................................................................................23
FIGURE 25: GUI TOGGLED OFF...........................................................................................................................................23
FIGURE 26: SW2 .............................................................................................................................................................24
FIGURE 27: DEREGISTRATION IN PROGRESS...........................................................................................................................24
FIGURE 28: "USERNAME REMOVED"MESSAGE ..................................................................................................................25
FIGURE 29: "REMOVE FAILED" ...........................................................................................................................................25
FIGURE 30: SW3 .............................................................................................................................................................26
FIGURE 31: SW3 .............................................................................................................................................................26
FIGURE 32: SW4 .............................................................................................................................................................27
FIGURE 33: REGISTRATION IN PROGRESS...............................................................................................................................27
FIGURE 34: SUCCESSFUL REGISTRATION................................................................................................................................28
FIGURE 35: REGISTRATION FAILED.......................................................................................................................................28
FIGURE 36: "WELCOME HOME"MESSAGE ...........................................................................................................................29
FIGURE 37: "LIST"COMMAND............................................................................................................................................31
FIGURE 38: "ADD COOPER"COMMAND ...............................................................................................................................31
FIGURE 39: "ADD -S"COMMAND........................................................................................................................................32
FIGURE 40: "DEL COOPER"COMMAND ................................................................................................................................32
FIGURE 41: "DEL -A"COMMAND.........................................................................................................................................32
FIGURE 42: "RENAME USER_0 COOPER"COMMAND ..............................................................................................................32
FIGURE 43: "VERBOSE 0"...................................................................................................................................................32
FIGURE 44: EXAMPLE VERBOSE MODE DEBUG MESSAGE.........................................................................................................33
FIGURE 45: ON-SCREEN INFO FOR REGISTERING FACE .............................................................................................................34
FIGURE 46: ON-SCREEN INFO FOR RECOGNIZED FACE..............................................................................................................34
FIGURE 47: "IR_PWM 60" COMMAND.................................................................................................................................35
FIGURE 48: "CAMERA IR PWM NOT SUPPORTED"MESSAGE ...................................................................................................35
FIGURE 49: "IR_PWM 60" COMMAND.................................................................................................................................35
FIGURE 51: "VERSION"COMMAND......................................................................................................................................35
FIGURE 52: "SAVE 3" COMMAND........................................................................................................................................36
FIGURE 53: "SAVE"COMMAND ..........................................................................................................................................36
FIGURE 54: "RESET"COMMAND .........................................................................................................................................36
FIGURE 55: "EMOTION 4" COMMAND SUCCESS OUTPUT.........................................................................................................37
FIGURE 56: "EMOTION 4"..................................................................................................................................................38
FIGURE 57: "LIVENESS OFF"COMMAND................................................................................................................................38
FIGURE 58: "LIVENESS ON"COMMAND ................................................................................................................................38
FIGURE 59: VGA VS.QVGA DETECTION RESOLUTION MAX RANGE ..........................................................................................39
FIGURE 60: "DETECTION RESOLUTION VGA"COMMAND...........................................................................................................39
FIGURE 61: "DETECTION RESOLUTION QVGA"COMMAND ........................................................................................................40
FIGURE 62: "DISPLAY OUTPUT_MODE IR"COMMAND .............................................................................................................40

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FIGURE 63: IR DISPLAY OUTPUT .........................................................................................................................................40
FIGURE 64: "DISPLAY MODE NOT SUPPORTED"MESSAGE.........................................................................................................40
FIGURE 65: RIVERDI DISPLAY..............................................................................................................................................41
FIGURE 66: "DISPLAY OUTPUT_DEVICE RIVERDI"COMMAND.....................................................................................................41
FIGURE 67: "DISPLAY INTERFACE LOOPBACK"COMMAND.........................................................................................................41
FIGURE 68: GUI TOGGLED OFF...........................................................................................................................................41
FIGURE 69: "WI-FI WILL START"MESSAGE ...........................................................................................................................42
FIGURE 70: "WI-FI DRIVER IS CONNECTING"MESSAGE............................................................................................................42
FIGURE 71: "WI-FI DRIVER IS ON"MESSAGE .........................................................................................................................42
FIGURE 72: "WIFI ON"COMMAND ......................................................................................................................................42
FIGURE 73: "WI-FI WILL STOP"MESSAGE.............................................................................................................................42
FIGURE 74: "WI-FI DRIVER IS OFF"MESSAGE ........................................................................................................................42
FIGURE 75: "WIFI RESET"COMMAND...................................................................................................................................43
FIGURE 76: "WIFI CREDENTIALS"COMMAND .........................................................................................................................43
FIGURE 77: "WI-FI CREDENTIALS NOT FOUND"MESSAGE........................................................................................................43
FIGURE 78: "WIFI CREDENTIALS"W/ARGS............................................................................................................................43
FIGURE 79: "WIFI CREDENTIALS"W/BAD ARG.......................................................................................................................43
FIGURE 80: "WIFI IP"COMMAND SUCCESSFUL.......................................................................................................................44
FIGURE 81: "WIFI IP"COMMAND UNSUCCESSFUL...................................................................................................................44
FIGURE 82: "WIFI ERASE"COMMAND ..................................................................................................................................44
FIGURE 83: "APP_TYPE"COMMAND....................................................................................................................................45
FIGURE 84: "LOW_POWER ON"COMMAND ..........................................................................................................................45
FIGURE 85: FACEREC MANAGER HOME SCREEN ....................................................................................................................46
FIGURE 86: "SMART LOCKS"MANAGEMENT PAGE.................................................................................................................46
FIGURE 87: BLE CONNECTIONS IN RANGE.............................................................................................................................47
FIGURE 88: CONFIGURE SMARTLOCK INFORMATION ...............................................................................................................47
FIGURE 89: "MANAGE SMART LOCKS"TAB...........................................................................................................................48
FIGURE 90: CONNECTED LOCKS...........................................................................................................................................48
FIGURE 92: REMOTE REGISTRATION SCREEN .........................................................................................................................49
FIGURE 91: REMOTE FACE CAPTURE SCREEN.........................................................................................................................49
FIGURE 93: "MANAGE USERS"TAB.....................................................................................................................................50
FIGURE 94: USER LIST SCREEN............................................................................................................................................50
FIGURE 95: REMOTE DELETION SCREEN................................................................................................................................51
FIGURE 96: LOW POWER TIMEOUT FLOW.............................................................................................................................54
FIGURE 97: "RECOGNITION TIMEOUT"MESSAGE ...................................................................................................................55
FIGURE 98: J3 SPEAKER CONNECTOR ...................................................................................................................................56
FIGURE 99: RIVERDI RVT28UEFNWC10 ............................................................................................................................56
FIGURE 100: "REGISTRATION FAILED"+VERBOSE MODE OUTPUT ............................................................................................59
FIGURE 101: BAD RGB LIGHTING .......................................................................................................................................59
FIGURE 102: BAD IR LIGHTING ...........................................................................................................................................60
FIGURE 103: IMPROPER FACE ANGLE &PROXIMITY................................................................................................................60
TABLE OF TABLES
TABLE 1: SUPPORTED COMPUTER CONFIGURATIONS .................................................................................................................8
TABLE 2: WI-FI FREQUENCY &POWER...................................................................................................................................8
TABLE 3: VERBOSE MODE CONFIGURATION TABLE..................................................................................................................18
TABLE 4: VERBOSE MODE ABBREVIATION TABLE ....................................................................................................................19
TABLE 5: PUSH BUTTONS FUNCTIONALITY .............................................................................................................................22
TABLE 6: SERIAL COMMAND TABLE......................................................................................................................................31

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TABLE 7: VERBOSE MODE CONFIGURATION TABLE..................................................................................................................33
TABLE 8: VERBOSE MODE ABBREVIATION TABLE ....................................................................................................................33
TABLE 9: EMOTION RECOGNITION CONFIGURATION TABLE.......................................................................................................37
TABLE 10: VGA VS.QVGA................................................................................................................................................39
TABLE 11: APP TYPE ARGUMENTS.......................................................................................................................................44
TABLE 12: APP CONFIGURATIONS........................................................................................................................................52
TABLE 13: REFERENCE DOCUMENTS ....................................................................................................................................62
TABLE 14: ABBREVIATIONS AND DEFINITIONS ........................................................................................................................63
TABLE 15: REVISION HISTORY.............................................................................................................................................63

6 SLN-VIZNAS-IOT User Guide, Rev. 1.1, 10/2020 NXP Semiconductors
1 Introduction
NXP’s MCU-based SLN-VIZNAS-IOT development kit provides OEMs with a fully
integrated, self-contained, software and hardware solution. This includes the i.MX
RT106F run-time library and pre-integrated machine learning face recognition algorithms,
as well as all required drivers for peripherals, such as camera and memories.
This cost-effective, easy-to-use face recognition implementation facilitates the demand
for a face-based “Friction Free Interface”that can be embedded in a variety of products
across home, commercial and industrial applications, thus eliminating the need to use
hard to learn and time-consuming mechanisms to identify users.
TARGET APPLICATIONS
•Safety/Security/Alarm devices: E-locks, Alarm panels, remote sensors, and
automated access
•Smart appliances: Washing machines, dryers, ovens, refrigerators, stoves, and
dishwashers
•Home comfort devices: Thermostats, remote temperature sensors, and lighting
•Counter-top appliances: Microwaves, coffee machines, rice cookers, and
blenders
•Smart industrial devices: Power tools, ergonomic stations, machine access and
authorization
1.1 RT106F VISION CROSSOVER PROCESSOR OVERVIEW
The i.MX RT106F is an EdgeReady member of the i.MX RT1060 family of crossover
processors, targeting low cost embedded face recognition applications. It features NXPs
advanced implementation of the Arm® Cortex®-M7 core, which operates at speeds up to
600 MHz to provide high CPU performance and best real-time responses. This i.MX
RT106F-based solution enables system designers to easily and inexpensively add face
recognition capabilities to a wide variety of smart appliances, smart homes, and smart
industrial devices. The i.MX RT106F processor is licensed to run NXPs i.MX RT run-time
library for face recognition which may include:
•Camera drivers
•Image capture
•Image pre-processing
•Face alignment
•Face tracking
•Face detection
•Face recognition
•Liveness Detection
•Emotion recognition

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1.2 Additional Peripherals
In addition to the i.MX RT106F, included in the kit are many additional peripherals
essential to experiencing everything the SLN-VIZNAS-IOT kit has to offer. Many of these
peripherals are shown in the figure below.
Figure 1: SLN-VIZNAS-IOT Additional Peripherals
Additionally, the SLN-VIZNAS-IOT kit comes with an IR+RGB Dual Camera Adapter like
that shown below for use in secure applications.
Figure 2: Dual Camera Adapter Kit Configuration
Depending on the mode of operation, devices using the Dual Camera Adapter can
emit highly concentrated non-visible infrared light which can be hazardous to the
human eye. Products which incorporate these devices must follow the safety
precautions given in IEC 60825-1 and IEC 62471.

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Recommended Computer Configuration
The MCU SLN-VIZNAS-IOT SDK requires an up-to-date computer which runs the
MCUXpresso IDE version 11.2. It also requires a terminal program to communicate with
the device via USB.
https://www.nxp.com/support/developer-resources/software-development-
tools/mcuxpresso-software-and-tools/mcuxpresso-integrated-development-
environment-ide:MCUXpresso-IDE
Table 1: Supported Computer Configurations
Usage Condition
The following information is provided per Article 10.8 of the Radio Equipment Directive
2014/53/EU:
(a) Frequency bands in which the equipment operates.
(b) The maximum RF power transmitted.
PN
RF Technology
(a) Freq Range
(b) Max Transmitted Power
SLN-VIZNAS-IOT
Wi-Fi
2412MHz-2472MHz
17.9dBm
Table 2: Wi-Fi Frequency & Power
EUROPEAN DECLARATION OF CONFORMITY (Simplified DoC per Article 10.9 of
the Radio Equipment Directive 2014/53/EU)
This apparatus, namely SLN-VIZNAS-IOT, conforms to the Radio Equipment Directive
2014/53/EU. The full EU Declaration of Conformity for this apparatus can be found at this
location: https://www.nxp.com/mcu-vision
**NOTE: See SLN-VIZNAS-IOT Developer’s Guide for information on changing preprocessor macros
Computer type
OS version
Terminal
Apple
Mac OS
PuTTY
PC
Windows 7 / 10
PuTTY/Tera Term
PC
Linux
PuTTY
To maintain EMC Compliance, the CLOCK_DRIVE_STRENGTH_LOW
preprocessor macro* must remain set to 1

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2 Get Started with SLN-VIZNAS-IOT
2.1 Box Contents
The SLN-VIZNAS-IOT kit arrives in a box alongside a printed Quick Start Guide and a
USB-C Cable.
Figure 3: SLN-VIZNAS-IOT Box Contents
Please check your kit for damage or marks, and, if seen, please contact your NXP
representative.
2.2 Running the Demo
To get started, take the USB-C cable provided inside the kit and plug the USB-A end into
your computer and the USB-C end into your kit.
Figure 4: Plugging in SLN-VIZNAS-IOT Kit
Once connected, a green LED (D1) will light up to indicate the kit is powered on.

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2.2.1 Access the Camera
NOTE: Camera enumeration is currently supported on Windows and Ubuntu.
With the kit powered on and connected to your computer, the SLN-VIZNAS-IOT kit will
automatically enumerate as both a serial device and USB camera device. To access the
kit’s camera, open Camera if using Windows, or Cheese, if using Ubuntu. In this guide,
we’ll be using Windows and the Windows camera app.
Figure 5: Windows Camera App

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After opening the camera app, video coming directly from the kit will be shown in the app’s
camera window:
Figure 6: SLN-VIZNAS-IOT Camera Output in Camera App
NOTE: The Windows Camera app has a “face finder” feature of its own, shown by the smaller blue
box around the face in the above screenshot.
If you have multiple cameras connected to your computer, you may need to change which
camera is being shown. In the Windows Camera app, this can be done by using the
“Change Camera” button located in the top right-hand corner of the app.
Figure 7: Change Camera Button in Windows Camera App

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2.2.2 Register a Face
To make full use of the face detection and recognition features of the SLN-VIZNAS-IOT,
you must register a face. To begin registering a new face, press the Manual Registration
button on the kit (SW4).
Figure 8: SLN-VIZNAS-IOT Manual Registration Button
Once pressed, a message indicating registration is taking place will appear at the top of
the screen, and the bounding box around the user’s face will turn from blue to green. To
register your face, stare straight-on at the camera while aligning your face inside the
bounding box. While registration is taking place, a “Registering” message will be shown.
Figure 9: Registration in Progress
NOTE: If pressing the button does not produce a “Registering” message, ensure that the “base”
board and “expansion” board are properly connected inside of the enclosure.
To cancel registration, simply press the registration button again, or, wait for the
registration process to timeout (~5s).

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Once successfully registered:
•A “USERNAME Added” message will be displayed
•The number of registered users will increase by one
•A username will be assigned to the registered face (usernames can be specified
through the CLI interface discussed in the following section)
Figure 10: Successful Registration
Should your face fail to register properly, either due to the registration being canceled or
timing out, a message like the following will be displayed:
Figure 11: Registration Failed
To retry, simply press the manual registration button again.
NOTE: If you are having trouble successfully registering a face, try adjusting proximity to the camera (either
closer or further away), slowly moving your head left-right and up-down so that the camera can get a better
view of different angles of your face, and ensure that the face being registered is sufficiently well lit for both
the IR and RGB cameras by adjusting the pwm values for the IR and white LEDs. For more information, check
out the Troubleshooting section near the end of this guide.

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Once registered, recognition of your face will prompt a “Welcome Home” message,
indicating the kit has detected a recognized face.
Figure 12: "Welcome Home" Message
Your face will continue to be recognized so long as the system is running. By default,
however, faces will be erased upon reset and must be explicitly saved into flash using the
“save” command if they should be retained (see Save Users Through Resets).
2.2.3 Liveness Detection and Anti-Spoofing
The SLN-VIZNAS-IOT comes with Liveness Detection and Anti-Spoofing turned ON
by default, meaning that the system can discern between your actual face and a print-
out/phone display picture of your face.
Figure 13: Phone Display Spoof Attack
By requiring a user’s actual face to be able to unlock the system, as opposed to a simple
picture of the user’s face, this feature helps to protect against some of the most common

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face recognition “spoof” attacks wherein a malicious actor will use a picture of someone
to gain access to their face-protected materials.
Figure 14: Printed Picture Spoof Attack
As shown in the screenshots above, using neither a phone display nor a printed picture
of a face triggers the “Welcome Home” message. In fact, if we enable verbose mode (see
2.2.5 Enable Verbose Mode) while attempting to recognize the printed picture in Figure
14, we can see that the inference engine detects a face, but recognizes that the image
captured by the IR camera is a “fake”/”spoofed” face.
Figure 15: Fake Face Detected

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2.2.4 Connect to Serial CLI
Using serial commands will give users access to the full suite of features the SLN-
VIZNAS-IOT has to offer. Issuing serial commands can be done via a serial terminal
emulator like PuTTY or Tera Term.
To connect to the serial CLI of the kit, identify the COM port associated with the kit and
connect using the [115200, 8, 1, N, XON/XOFF] serial settings shown below.
Figure 16: Serial Connection Settings
After connecting to the kit’s serial interface, you will encounter a blank terminal screen
that echoes any characters that you type. Use the “help” command to display a list of all
the available serial commands and their usage. We will be discussing a few of these
commands in the upcoming sections.

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Figure 17: Serial Commands "Help" Menu
SHELL>> help
"help": List all the registered commands
"exit": Exit program
"list": List all registered users
"add username": Add user
"add -s": Stop the former add command issued
"del username": Delete user
"del -a": Delete all users
"rename oldusername newusername": Rename user
"verbose <0|1|2|3> (none-all)": Debug message detail level setting
"camera ir_pwm <value>": PWM pulse width for IR led, value should be between 0 (inactive) to 100
"camera white_pwm <value>": PWM pulse width for white led, value should be between 0 (inactive) to 100
"version": The version information
"save n": Save database into flash memory
"updateotw": Reboot the board and start the OTW firmware update
"reset": Reset the MCU
"emotion <0|2|4|7>"
"liveness <on|off>"
"detection resolution <qvga|vga>": Set detection resolution and reset
"display output_mode <rgb|ir>"
"display output_device <usb|riverdi>"
"display interface <loopback|infobar>"
"wifi <on|off>": Turn the Wi-Fi connection on|off
"wifi reset": Reset wifi to re-link.
"wifi credentials": Get the credentials.
"wifi credentials SSID [PASSWORD]": Set Wi-Fi credentials.
"wifi ip": Get the ip address.
"wifi erase": Erase the Wi-Fi credentials from flash
"app_type <0|1|2|3|4>":
0 - Elock(light)
1 - Elock(heavy)
2 - Door access(light)
3 - Door access(heavy)
4 - Userid
"low_power <on|off>": Turn low power mode on|off

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2.2.5 Enable Verbose Mode
The SLN-VIZNAS-IOT kit supports debug message logging which provides important
inference performance information, for example, the time it took to detect a user. Serial
debug messages are disabled by default but can be enabled via a serial command.
To enable serial debug output, type the serial command “verbose 0”, “verbose 1”,
“verbose 2”, or “verbose 3.”
Figure 18: "verbose 0"
Using the verbose command will enable logging of the debug information indicated in
the table below.
Message Type
Importance
“verbose 0”
“verbose 1”
“verbose 2”
“verbose 3”
Critical
High
X
X
X
Detailed
Medium
X
X
Misc.
Low
X
On-screen
Debug Info
N/A
X
Table 3: Verbose Mode Configuration Table
The following is an example of a debug message a user might receive after a face
detection and recognition event.
Figure 19: Example Verbose Mode Debug Message

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The following table describes the different messages and the associated descriptions.
Abbreviation
Definition
dt
Time taken to detect face
rt
Time taken to recognize face
sim
Predictive accuracy/confidence value of face rec
face_id
Internal face database identifier
Table 4: Verbose Mode Abbreviation Table
In addition to debug logging over serial, enabling “verbose 3” will also display some
useful on-screen information as well that can be helpful when troubleshooting
registration/recognition issues. An example can be seen in the images below:
NOTE: Without any registered users, the on-screen debug info will not update until a registration
has been triggered. This is because the inference engine does not attempt to recognize any faces
if they are none currently registered.
Figure 20: On-screen Info for Registering Face
In the above example, registration is taking place, but according to the on-screen
debugging info, although the face has passed the blurriness check (hence “blur: 0”), the
“front face check” has passed (hence “front: 1”), and the RGB liveness check has
passed (hence “rgbLive: 1”), the IR liveness check has not passed (hence “irLive: 0”).
This would suggest that there may be an issue with the IR camera –likely a lighting issue.

20 SLN-VIZNAS-IOT User Guide, Rev. 1.1, 10/2020 NXP Semiconductors
Figure 21: On-screen Info for Recognized Face
In this example, the on-screen info reflects information about the face being recognized.
As shown in the screenshot, the face has been recognized with 95% similarity to the
matching face in the internal database (hence “sim: 95”) and has passed both the RGB
and IR liveness checks (hence “rgbLive: 1” and “irLive: 1”).
NOTE: The “front face check” is only performed by the inference engine for faces being registered
to ensure that no face gets registered that it is improperly angled towards the camera. For this
reason, the “front” value will not change unless a registration is being performed.
2.2.6 (Optional) Enable Low Power Mode
For many use cases, managing power consumption is critical. Fortunately, the SLN-
VIZNAS-IOT supports low power features out-of-the-box. Low power mode functionality
can be enabled or disabled through the use of the serial commands.
Use the command “low_power on”or “low_power off” to enable or disable the low
power mode feature supported on the SLN-VIZNAS-IOT.
When low power mode is enabled, the SLN-VIZNAS-IOT will automatically
sleep/hibernate in a state of much lower power consumption than normal, when no
registration/deregistration is taking place and no activity is detected by the camera for
~20s. A “recognition timeout” message like the one shown in Figure 22 will be displayed
on screen as a warning that the SLN-VIZNAS-IOT will be entering sleep mode within the
next 5 seconds.
SHELL>> low_power on
SHELL>> Low power mode enabled.