Devices - Internet Of Things

• Sensing
• Actuation
• RFID (Radio Frequency Identification)
• Wireless Sensor Network (WSN)

Sensing

• Obtaining value for a specific property
• Types
  • Based on Output
    • Analog
      • Gives continuous output signals
    • Digital
      • Gives non-continuous (Discrete) output signals
      • Binary values
  • Based on DataType
    • Scalar
      • Measuring magnitude of value
    • Vector
      • Measuring magnitude & direction of value

Actuation

• Component of a machine that provides movement to perform a specific task
• Takes Control Signal (CS) and Source Energy
• Movement
  • Linear
  • Rotating
  • Oscillating
• Types
  • Hydraulic
    • Actuator is a cylinder containing liquid to generate pressure that creates force
  • Pneumatic
    • Actuator is a cylinder containing high pressured compressed air to generate pressure that creates force
    • Response is quicker as compared with hydraulic
  • Electrical
    • Electrical signals are used that trigger mechanical motion
    • Converts electrical to mechanical energy
  • Thermal
    • Temperate sensitive material is used that expands or contracts with change in temperature which is used to generate mechanical motion
  • Magnetic
    • Electric current is used to generate magnetic flux via a Coil that generates mechanical motion
  • Mechanical
    • Rack and Pinion mechanism is used to convert rotational motion into linear motion

RFID (Radio Frequency Identification)

• RFID Tag
  • Data is encoded and stored in this tag
• RFID Reader
  • Data is decoded from the tag
• 
• Components
  • Integrated Circuit (IC)
  • Antenna
  • Protective Covering
• Types
  • Passive
    • Dependent of RFID reader for power supply
    • Smaller in size
  • Active
    • Has its own power supply
• Automatic Identification and Data Collection (AIDC)
  • Less human intervention to identify object and map that data to computer system
  • Wired connection
  • RFID uses AIDC using radio waves

Wireless Sensor Network (WSN)

• Network is made up of Sensor Nodes
• Sensor Nodes Components
  • Sensors
  • Sensing Unit
  • Communication Unit (Transreceiver)
  • Processing Unit
  • Storage Unit
  • Analog to Digital Converter (ADC)
  • Power (Battery)
    • Has very limited life span
  • Options => Can add
    • Location => Used in mobile Sensor Nodes
• Sensor Nodes Types
  • Stationary
    • Stays in the same location and communicates with other nodes
  • Mobile
    • Arial Sensor Nodes
      • Moves above land (on Air)
    • Terrestrial Sensor Nodes
      • Moves on land
    • Underwater Sensor Nodes
      • Moves below land (on Water)
• Sensor Nodes Features
  • Size should be as small as possible
  • Power consumption should be low
  • Should have adaptive nature w.r.t environment
  • Tiny OS is generally used
  • Multihop Path
    • Data travel from Source to Sink/Gateway to Internet to User
    • When having short radio transmission range, data can not be transferred from Source to Sink at once
    • Source will use other nodes in the network which will act as Relay nodes to transfer data
• WSN Types
  • Stationary Wireless Sensor Network (SWSN)
    • Stationary Sensor Nodes are present
    • Node failure can lead to disconnection of the network
  • Mobile Wireless Sensor Network (MWSN)
    • Mobile Sensor Nodes are present
    • Faliure node can be Healthy node to connect network