Wednesday, 13 June 2012
Sunday, 27 May 2012
Scrape or retrieve data from a website using LabVIEW. This is also called data harvesting or data extraction from websites.
One difficulty is finding good HTML data to scrape. Most data like stock quotes have been replaced with dynamic data that doesn't have a clear and consistent text strings that can be searched.
Here is an example that opens a URL website, reads the HTML, picks out a string keyword and displays the data after that keyword. I've chosen a weather site that has a consistent keyword like "temp"> and the page is dedicated to only one city. So the number after "temp"> will be that city's temperature.
This vi will be great for any instrument attached to a network with a web-page to access.
One difficulty is finding good HTML data to scrape. Most data like stock quotes have been replaced with dynamic data that doesn't have a clear and consistent text strings that can be searched.
Wednesday, 23 May 2012
LabVIEW Web UI Builder is a Web-Based LabVIEW programming Environment that gives you the ability to develop lightweight VI's without needing to purchase LabVIEW.
Practice creating and programming VI's now. Try It Now Create your account to start programming with LabVIEW.
LabVIEW Web UI Builder is free to try out for an unlimited amount of time. Anyone can create an account and develop an application that runs inside the editor. Users can save their work to cloud storage or, if the editor is installed locally, to a local hard drive. The only feature that is not available for free is the ability to build and deploy standalone web applications that no longer require the editor.
I loaded it on my computer and tried it out… It’s awkward to use but it works.
Here are some screen prints and the example vi…
Monday, 26 March 2012
So you've completed STEP #1 Get LabVIEW and you've worked through the examples given in the tutorials. Then you followed STEP #2 Get an Arduino. You checked out your Arduino and now you are ready to program the LIFA files onto the Arduino with STEP #3 Load LIFA.
You need some way to test that everything is connected and working. You also need to get familiar with both LabVIEW and Arduino together.
Your first LabVIEW project needs to be something very simple and easy to understand. Most programming languages and starter circuits always have a "HELLO WORLD" to learn from.
Controlling an LED with an on-screen switch would be an easy way you can interface the on-screen controls of the LabVIEW Front Panel with the real-world LED connected to an output of the Arduino.
You can start by adding a switch, a stop button and an indicator LED to your first front panel. You can also add these items from the Block Diagram.
You need some way to test that everything is connected and working. You also need to get familiar with both LabVIEW and Arduino together.
Your first LabVIEW project needs to be something very simple and easy to understand. Most programming languages and starter circuits always have a "HELLO WORLD" to learn from.
Controlling an LED with an on-screen switch would be an easy way you can interface the on-screen controls of the LabVIEW Front Panel with the real-world LED connected to an output of the Arduino.
You can start by adding a switch, a stop button and an indicator LED to your first front panel. You can also add these items from the Block Diagram.
The Block Diagram shows the connection details of my Arduino Clone. Your settings may very depending on what Arduino device you have connected. You can always find the com port in your control panel, Hardware manager of Windows. Plug your Arduino into the USB jack and see what com port is listed when it connects.
LabVIEW has a free 30-day evaluation copy you can download at National Instruments or you can purchase the LabVIEW 2009 Student Edition
Once you install LabVIEW on your computer, you can go through the "Getting Started with LabVIEW" tutorials which help you get familiar with the inner workings of LabVIEW. You can learn how to convert degrees C to F by using only mathematical terms and the front panel controls. I've seen on YouTube video on building a calculator using LabVIEW. It's a bit long and tedious to build but it's a valuable learning experience if you work through it.
The first equipment you will need is an Arduino or compatible device. Here are photos of my Arduino's.
I bought the small board on the left from http://www.adafruit.com/ and the red board connected is the USB to
Arduino board I bought from http://www.sparkfun.com/products/9716
The board on the right is just a block of LED's and a pushbutton connected to the Arduino as outputs and inputs.
I used the USB board and connected it to a proto-board with a 10uf and 16MHz ceramic resonator which creates an Arduino compatable device.
 |
| UNO R3 |
All of these devices can be used to interface with LabView.
Setting up the LabVIEW Interface for Arduino (LIFA) is a six step process that you will only need to complete once you get LabVIEW setup on your computer and you have an Arduino or compatible device. Please follow the instructions below to start creating applications with the LabVIEW Interface for Arduino. LabVIEW Interface for Arduino Setup Procedure
Nice overview of using Labview-and-Arduino
Nice overview of using Labview-and-Arduino
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