This document describes an IoT-based surveillance system that uses sensors to acquire data. A Raspberry Pi is used as a gateway device connected to sensors on a Sensor Tag to measure environment variables. The sensor data is published to the cloud using MQTT protocol and can be monitored remotely. A camera is also used to stream visual data to a server.

1. IoT Implementation of Sensor
Data Acquisition in
Surveillance Applications
Presented by
ARUN JOE JOSEPH
Roll No: 8
S3 M.Tech VLSI & ES
3February2016
1

2. Introduction
• Surveillance is an important aspect of both military and
civilian security, anywhere in the world.
• It is essential to gather data or intelligence in different forms,
to add an extra layer of security in either one of the cases.
• In this project, we implement an IoT powered surveillance
equipment.
3February2016
2

3. Introduction
3February2016
3

4. Objective
• Our aim in this project is to implement Internet of Things (IoT)
model for surveillance which:
• Acquires data using sensors.
• Pushes the collected data into the Cloud / Server.
• Monitor this data using a remote terminal in the network.
3February2016
4

5. Methodology
• Raspberry Pi is used as a gateway device for the sensors that
are used to collect data.
• Sensor tag consisting of different sensors, is used to measure
different environment variables.
• MQTT protocol is used to publish and subscribe the sensor
data into and from the cloud.
• Visual data is also collected using a camera. The collected data
is streamed to a server/ cloud platform, where it can be
monitored.
3February2016
5

6. Literature Review
3February2016
6

7. Internet of Things - IoT
• The Internet of Things (IoT) is an environment in which
objects, animals or people are provided with unique
identifiers and the ability to transfer data over a network
without requiring human-to-human or human-to-computer
interaction. IoT has evolved from the convergence of wireless
technologies, micro-electromechanical systems (MEMS) and
the Internet. The concept may also be referred to as the
Internet of Everything.
3February2016
7

8. Internet of Things – IoT (contd.)
3February2016
8

9. Internet of Things – IoT (contd.)
3February2016
9

10. Internet of Things – IoT (contd.)
3February2016
10

11. Raspberry Pi
3February2016
11

12. Raspberry Pi - Technical
Specifications
• Broadcom BCM2836 Arm7 Quad Core Processor powered
Single Board Computer running at 900MHz
• 1GB RAM
• 40pin extended GPIO
• 4 x USB 2 ports
• 4 pole Stereo output and Composite video port
• Full size HDMI
• CSI camera port for connecting the Raspberry Pi camera
• DSI display port for connecting the Raspberry Pi touch screen
display
• Micro SD port for loading your operating system and storing
data
• Micro USB power source
3February2016
12

13. No – IR Camera
3February2016
13

14. No – IR Camera Features
• 5 megapixel native resolution sensor-capable of 2592 x 1944
pixel static images
• Supports 1080p30, 720p60 and 640x480p60/90 video
• Camera is capable of 2592 x 1944 pixel static images
• No Infrared filter making it perfect for taking Infrared
photographs or photographing objects in low light (twilight)
conditions
• 1.4 µm X 1.4 µm pixel with OmniBSI technology for high
performance (high sensitivity, low crosstalk, low noise)
• Optical size of 1/4"
3February2016
14

15. Sensor Tag CC2650
3February2016
15

16. Sensor Tag Features
• Supports 10 Low-Power Sensors
• Ambient Light
• Infrared Temperature
• Ambient Temperature
• Accelerometer
• Gyroscope
• Magnetometer
• Pressure
• Humidity
• Microphone
• Magnetic Sensor
3February2016
16

17. Sensor Tag – Block Diagram
3February2016
17

18. Design and
Implementation
3February2016
18

19. Block Diagram
3February2016
19

20. Raspberry Pi – Camera
Interfacing
• Simple approach to streaming video using a buffer and a raw
byte stream.
• Leads to small delays (<100ms) and a high frame rate (~30fps)
of the streamed video, making it perfect for live video
streaming and feedback.
• Raspberry Pi used a utility called netcat to send data from the
Pi to the computer.
3February2016
20

21. Raspberry Pi – Camera
Interfacing (contd.)
• On the receiving computer, we streamed the video through
the open source video player mplayer and used netcat to
capture the video bits that were sent from the Pi.
• Computer we use is made ready to accept the data that the
Raspberry Pi sends by running the following command in a
terminal.
• nc.traditional -l -p 5000 | mplayer -fps 60 -cache 1024 -
•
3February2016
21

22. Raspberry Pi – Camera
Interfacing (contd.)
• We use netcat to open up a connection on port 5000 of your
computer for receiving bytes from a connection, which is then
send (pipe) to the mplayer application used to play the video.
• The additional flags set the desired frame rate of the video to
60 frames per second and sets the video cache size to 1024
bytes.
3February2016
22

23. Raspberry Pi – Camera
Interfacing (contd.)
• At transmitting end, video bytes are captured from the camera
and saved into the fifo.500 pipe.
• The pipe essentially acts as a FIFO (first-in first-out) buffer that
stores the video bytes as they arrive and allows the bytes to
be read from the buffer by other utilities.
• We then use the netcat utility to read bytes from the
pipe and send them off to the receiving terminal that we’ve
already set up to wait for transmitted data.
•
3February2016
23

24. Raspberry Pi – Camera
Interfacing (contd.)
• mkfifo fifo.500
• Pipe fifo.500 ready to receive and send bytes.
• cat fifo.500 | nc.traditional <your ip> 5000 &
• We use the netcat utility to send any bytes that may be
written into the pipe off to port 5000 on the computer that
we’ve set up.
• /opt/vc/bin/raspivid -o fifo.500 -t 0 -b 10000000
• We use the built-in video capture script raspivid on the
Raspberry Pi to write data into the pipe created above.
• The -t parameter - time for which the video capture script
should capture video. Setting the -t parameter to 0 makes the
video stream with no timeout. The -b tag indicates the bitrate
of the video stream.
3February2016
24

25. Raspberry Pi – Sensor tag
CC2650 interfacing
• Raspberry Pi is interfaced to the TI Sensor tag using a
Bluetooth Low Energy (BTLE) BT 4.0 adapter connected to the
Raspberry Pi.
• CC2650 SensorTag is a BLE peripheral slave device.
• Python code is written to scan for the nearby Bluetooth
devices advertising its MAC ID.
• During the scan, the sensor tag must be turned on, for it to be
discovered.
3February2016
25

26. Raspberry Pi – Sensor tag
CC2650 interfacing (contd.)
• On start-up, the SensorTag advertises with a 100 millisecond
interval indicated by the green LED blinking at a 1 Hz rate.
Advertising can be stopped/started by pressing the power
button. The SensorTag MUST be advertising for the device to
be discoverable by the gateway device.
• The central device can only connect to a SensorTag that is
advertising.
• In the advertising state the central device can:
• Scan and discover the Sensor Tag. (Scan response contain name
“CC2650 SensorTag”).
• Establish connection based on user defined Connection
Parameters.
3February2016
26

27. Raspberry Pi – Sensor tag
CC2650 interfacing (contd.)
• The connection is established by the Central Device and the
sensors can then be configured to provide measurement data.
• When connected the central device can:
• Discover Characteristic by UUID.
• Write to and read from Characteristic Value (configure sensors
and read data).
• Disconnect the device and return it to an advertising state.
• To obtain the data, the corresponding sensor must first be
activated, which is done via a Characteristic Value write to
appropriate service.
3February2016
27

28. Raspberry Pi – Sensor tag
CC2650 interfacing (contd.)
• The most power efficient way to obtain measurements for a
sensor is to:
• 1. Enable notification
• 2. Enable Sensor
• 3. When notification with data is obtained at the Master side,
disable the sensor (notification still on).
3February2016
28

29. Raspberry Pi – Sensor tag
CC2650 interfacing (contd.)
• The sensors are enabled by writing 0x01 to the
corresponding configuration characteristic and then disabled
by writing 0x00.
• Since the SensorTag reference platform supplies the raw,
uncalibrated sensor outputs to the IoT enabled Raspberry Pi,
necessary calibration for the operating environment is to be
performed.
3February2016
29

30. Raspberry Pi – Sensor tag
CC2650 interfacing (contd.)
• When an enable command (0x01) is written to
the configuration characteristic, the sensor starts to perform
measurements each second (average over four
measurements) and the data is stored in
the data characteristic.
• When the disable command (0x00) is issued, the sensor is put
in stand-by mode and no data are cleared and no longer
reported.
3February2016
30

31. MQTT Publish & Subscribe
• Data obtained from the sensor tag is converted into a format
known as JSON (Java Script Object Notation) format.
• Why JSON?
• JSON is a valid subset of JavaScript, Python, and YAML.
• JSON parsing is generally faster than XML parsing.
• JSON is a more compact format, meaning it weighs far less on the
wire than the more verbose XML.
• JSON is easier to work with in some languages (such as javascript,
python, and php).
• Formatted JSON is generally easier to read than formatted XML.
• JSON specifies how to represent complex datatypes, there is no
single best way to represent a data structure in XML.
3February2016
31

32. MQTT Publish & Subscribe (contd.)
• This JSON data is published to the cloud using MQTT (Message
Queue Telemetry Transport) protocol.
• Why MQTT?
• Easy, Binary, Minimal overhead.
• Data agnostic.
• Publish / Subscribe.
• Push instead of Pull.
• Reliable even when used with unreliable networks, constrained
devices.
• Low bandwidth, high latency use case.
3February2016
32

33. MQTT Publish & Subscribe (contd.)
• mosquitto_sub -t “CC2650”
• The client can subscribe to multiple topics, downgrade topic
subscriptions to a lower QoS, provide an ID for persistent
sessions, define a will message, and many other options.
(mosquitto_sub -h will list them.)
• mosquitto_pub -t “CC2650" -m "message payload" -q 1 –r
• This will publish a message to a given topic at QoS 1, retained.
Many options will be listed by mosquitto_pub -h.
3February2016
33

34. MQTT Publish & Subscribe (contd.)
3February2016
34

35. MQTT Publish & Subscribe (contd.)
3February2016
35

36. MQTT Publish & Subscribe (contd.)
• Last known good value
• Broker saves last message for a topic.
• Client decides if the message is retained.
• Client receives the retained message after subscribing.
• Client defines Last Will and Testament.
• Broker sends message on behalf of the client after the client
‘died’.
• Real push.
• Useful for implementing on/off topic publishes.
• Mosquitto is an open source message broker that implements
the MQTT protocol.
3February2016
36

37. Boot time execution of scripts
• The python and shell scripts are run at boot time using a
crontab utility, using which scripts can be scheduled to be
executed after booting.
• The crontab is a list of commands that you want to run on a
regular schedule, and also the name of the command used to
manage that list.
• The below commands are appended to the crontab.
• @reboot sh /home/pi/launcher.sh >/home/pi/logs/cronlog 2>&1
• @reboot sleep 60 && sh /home/pi/livestream.sh
• Here, launcher.sh is executed at boot time and creates a
cronlog, while livestream.sh is executed 60 seconds after the
boot.
3February2016
37

38. Boot time execution of scripts
(contd.)
3February2016
38

39. Boot time execution of scripts
(contd.)
3February2016
39

40. Conclusion
3February2016
40

41. Conclusion (contd.)
• The objectives of the project have been accomplished.
• Published sensor data into the cloud using MQTT protocol via
Raspberry Pi as the gateway device.
• Subscribed to the sensor data in the cloud using MQTT via a
remote terminal.
• Implemented Live streaming of Low light visual data for
surveillance application.
3February2016
41

42. References
1. http://zacharybears.com/
2. https://www.raspberrypi.org
3. http://processors.wiki.ti.com/
4. http://mqtt.org/
5. https://github.com/
6. http://hackaday.com/
7. http://spin.atomicobject.com/
8. https://en.wikipedia.org
3February2016
42

43. THANK YOU
3February2016
43