LJStreamUD V1.09 has been posted.  Go to the LJStreamUD support page.

Mounting Stand and Circuity Complete

On the left is the 24V power supply, in the middle is the U3, and on the right lies the power switching circuit designed during "Phase 2" of this project. 

The mounting stand is comprised of 5/8" threaded rod situated in a PVC base.  There are large threaded nuts at the start of the PVC to allow for height adjustment. 

The solenoid valves are all wired into the power switching circuit, which is controlled through the EIO, CIO, and FIO lines on the U3. Using a python script running on a local PC the valves are opened and closed. The next step is to buy a bunch of alcohol and connect the piping.

Linux and Mac OS X users, prepare to get happy. For years we’ve had great language support for C and Python through the Exodriver and LabJackPython, and we’ve recently documented how to use LabVIEW on Mac OS X to call the Exodriver. We wanted programmers in other languages to leverage the work we’ve done, so we’re releasing LJFuse. LJFuse is a program that creates files for all the connections on a LabJack. For example, to read analog input AIN0 on a U6, read a file named “AIN0”:

  
$ cat MyU6/connection/AIN0
2.500
  

Now the problem of reading and writing to a USB LabJack has been reduced to reading and writing to a file. To show how simple it is, we wrote sample applications in the shell, C, Python, Ruby, PHP, Perl, Java, Scala, and LabVIEW. Here’s the sample Ruby application that logs AIN0 once per second with a timestamp in CSV format:

Without LJFuse, this type of application isn’t possible in Ruby. Even in C and Python, where it was possible without LJFuse, it’s now even simpler.

LJFuse isn’t perfect. Simple things are really simple (trivial), but hard things are still hard or impossible. If you have a use for LJFuse that isn’t simple yet, let us know.

Beta U3 firmware 1.30 adds the new Line-to-Line timer mode that can measure times between edges on two different lines with up to 20.8ns resolution. For more information see section 2.9.1.12 of the user's guide: http://labjack.com/support/u3/users-guide/2.9.1.12

We have started a new application note about arbitrary waveform generation with DAC channels (analog outputs).

In response to user demand, we have added new C# examples to our UD .NET example archive. These new additions include a GUI form that updates itself at regular intervals and two streaming examples, one using a traditional thread and another using a software timer. The updated archive can be found at http://labjack.com/support/ud/examples/dotnet

Best of luck,
LabJack Support

We have seen a few attempts from customers to try to create CINs for LabVIEW on Mac OS X. Here’s an example. We decided to try it ourselves, and it turned out be be a little more complicated than we had originally expected. In order to help future customers, here are the steps we took to build a CIN:

For the sake of this tutorial, we have installed LabVIEW 2009 to the default location of:

  
"/Applications/National Instruments/LabVIEW 2009/"
  

and Xcode 3.2.2 installed in its default location:

  
/Developer
  

Step 1: Get the CIN template to appear in Xcode

Copy the “LabVIEW Templates” directory from

  
/Applications/National Instruments/LabVIEW 2009/cintools/Xcode Files
  

to:

  
/Developer/Platforms/MacOSX.platform/Developer/Library/Xcode/Project Templates
  

Step 2: Create a blank CIN Project

Launch Xcode and create a new project, there should now be a section called “LabVIEW Templates” with a template called “CIN 9.0”. Click that and give your project a name.

Step 3: Set the correct architecture

Right-click on your project’s blue icon and select “Get Info”. From there, click the “Build” tab.

In the section called “Architectures”, click the “Architectures” sub-section and select “Other”.

Today DASYLab officially joins our growing selection of UD-family compatible software. Now, with the 0.1 release of LabJackDasy, users can communicate with U3, U6, and UE9 devices using DASYLab’s native controls. The following features are currently supported:

• Analog input
• Digital input
• Digital output
• Streaming
• On-board DAC
• Channel configuration
• Connection over both Ethernet and USB with LocalID

In response to customer feedback, timers and counters will be implemented for the next release. Also, as this is an alpha release, developers should review the limitations listed in the project’s Readme file.

Check it out on the new LabJackDasy page and, as always, we are looking forward to seeing what amazing applications our customers have for this new offering.

Circuit Design and Valve Placement

The drink elements will flow when their corresponding valve is opened, so I designed a circuit capable of switching power for each solenoid valve.  The AutoBart will be a modular system, starting with the capacity for 12 drink elements, but having the option of expanding to 24, or 36.  

The signal lines are isolated from the external 24V power supply through an opto-isolator, the FETs will be fuse protected and capable of ~1A, and each channel has an LED indicator.   The screw terminals and DB15 connector are arranged like the CB15 Terminal Board, so it will be compatible with any LabJack.  The next step will be to solder in components and write software.

Valve Pressure/Flow Testing

The humble beginnings of an automated bartender.  When complete, it will be a system of valves controlled through a LabJack that can dispense your favorite cocktail at the press of a button.  The test scenario above involves a 24V DC solenoid valve, a pressure tank filled with air to 20psi, a 2-litre bottle of Dr. Pepper, and some 1/4" nylon tubing.  Next phase: Assemble a circuit to interface a LabJack with the solenoids.