Home security system with remote user interface

• A complete example of a medium-complexity system controller modelled on an actual home security system product
• Use as a template for your own embedded control and monitoring application software architecture that promotes reliability, scalability, and maintainability
• Visualizes internal states and interactions of the system
• Uses virtual I/O devices so that you can experience the system immediately, but is straightforward to upgrade to physical devices from the NI Project Essentials Guide:
  • Keypad
  • LCD display using either SPI, I2C, or UART interface
  • Hall-effect sensor or photointerrupter as the door sensor
  • Sonic range finder as the motion sensor
• Coding techniques illustrated:
  • Queued message handler (QMH) for multiple parallel process loops that interact with each other through message queues
  • Queued state machine (QSM) to implement behavior within each process loop
  • Event-driven producer-consumer state machine to implement a responsive user interface on the PC host
  • Network-published shared variables (NPSVs) bound to front-panel indicators to monitor state of the RT controller application
  • Network stream for sending command messages to RT

Real-time audio processor

• Use a custom FPGA personality to acquire stereo audio from the Academic RIO Device “Audio In” port, stream the audio to the RT target by DMA FIFO or to the PC host by DMA FIFO for processing, and stream it back through the FPGA to the “audio out” port
• A similar example demonstrates how to stream from the FPGA to the RT (by DMA FIFO) and then stream from the RT to the PC with network streams
• Coding techniques illustrated:
  • High-speed data streaming with DMA FIFOs
  • High-speed data streaming with network streams
  • Full custom FPGA VI
  • Audio I/O ports

Headless datalogger (file I/O)

• “Headless” means the datalogger application has an empty front panel; all interaction with application takes place through network files
• Monitor process variables and sensor measurements, timestamp them, and log them to a file
• Remote access the datalog file through the network with WebDAV, web browser, or HMI (human-machine interface) VI running on a PC host
• Control the datalogger application by editing the remote configuration file either manually or through the HMI

Remote webcam photo logger

• Capture a webcam image at a user-defined interval
• Save the images to a USB thumbdrive
• Email the image as an attached file
• Coding techniques illustrated:
  • Timer interrupts and interrupt handling
  • External interrupts
  • File system I/O
  • SMTP email

High-precision waveform measurement

• Obtain high precision (high time resolution) by an FPGA-based measurement
• Measure the width of the high-level portions of a digital signal
• Investigate the pulse width of signals generated by the FPGA as well as by the RT target to experience and better understand jitter
• Coding techniques illustrated:
  • Augment the Academic RIO Device FPGA personality with custom FPGA functionality while retaining the Academic RIO Device Toolkit features, i.e., Express VIs and low-level VIs
  • Timed loops on the RT target

Call a web service

• Retrieve information stored in an online database:
  • Current weather data
  • Latitude and longitude of an address
• Post photos to Twitter and Instagram
• Learn more technical information about web services, especially the fundamental concept of calling a web service
• Coding techniques illustrated:
  • Form a query string as the URL of a Web service
  • Retrieve the JSON string served by the Web service
  • Parse the JSON string to extract useful information
    
    

Host a web service

• Serve any information available to the Academic RIO Device to a remote client:
  • Onboard sensors (push button, accelerometer)
  • Digital and analog I/O
  • External sensors and controls
• Use information sent by the remote client to control system state and external indicators and actuators
• Learn more technical information about web services, especially the fundamental concept of hosting a web service
• Coding techniques illustrated:
  • Serve system information: date, time, and IP address
  • Serve the state ob onboard devices
  • Retrieve information as JSON strings for machine-to-machine communication
  • Retrieve information as a web page
    

TCP and UDP networking: “ping”

• Use low-level UDPUser Datagram Protocol, a connectionless protocol based on sending data packets known as datagrams, a word play on “data” and “telegrams” and TCPTransmission Control Protocol, a connection-based means to send and receive data packets with guaranteed reliability Internet protocols to communicate messages between LabVIEW applications as well as other systems
• Develop an IoTInternet of Things, i.e., networking in the context of machine-to-machine interactions; ubiquitous communication ability of embedded systems. application based on well-established Internet standards
• Choose UDP for connectionless simplicity or connection-based TCP for guaranteed reliability
• Experiment with the UDP “ping” and TCP “ping” applications to “bounce” a message to/from another host on the network
• View the all known IP addresses for the PC host and RT target
• Coding techniques illustrated:
  • Open a TCP connection, send and receive messages, listen for remote hosts to request a connection
  • Send and receive UDP datagrams
  • Look up all IP addresses of the host

TCP and UDP networking: client-server

• Use low-level UDPUser Datagram Protocol, a connectionless protocol based on sending data packets known as datagrams, a word play on “data” and “telegrams” and TCPTransmission Control Protocol, a connection-based means to send and receive data packets with guaranteed reliability Internet protocols to communicate messages between LabVIEW applications as well as other systems
• Develop an IoTInternet of Things, i.e., networking in the context of machine-to-machine interactions; ubiquitous communication ability of embedded systems. application based on well-established Internet standards
• Choose UDP for connectionless simplicity or connection-based TCP for guaranteed reliability
• Experiment with the UDP client-server and TCP client-server applications to send a client request from the PC host to the server running on the Academic RIO Device; the client controls onboard peripherals on the Device and receives Device sensor information
• View the all known IP addresses for the PC host and RT target
• Coding techniques illustrated:
  • Open a TCP connection, send and receive messages, listen for remote hosts to request a connection
  • Send and receive UDP datagrams
  • Look up all IP addresses of the host

Related content

Tags:

• application example

Targets:

• RIO