What kind of things can be done with a LabJack?

Here is a good forum topic about frequency measurement:

http://forums.labjack.com/index.php?showtopic=1105

You are probably going to want the U3 or U6, and you will probably use a timer in 32-bit period measurement mode.  There is really no minimum Hz limit.  If the signal was too slow, you could always switch to software timing to go as long as you want.  The 32-bit period measurement mode will certainly work for your 0.5 - 30 Hz range.

I searched around and did not find any other mention of SpectraPlus software.  If the software has an open API that lets you call functions from a Windows DLL then you should be able to talk to a LabJack yourself, otherwise PHS would have to add the support.

There are no plans to port LabJackPython to Python 3.x.  We are currently developing a multi-platform Modbus driver, and have not decided what Python versions we will support in that interface.

Reading a couple pots is pretty straightforward.  A U3-HV is probably what you should look at.  As for controlling the motor, unless the motor is very small you need something between the U3 and the motor.  Perhaps you use a PWM output timer on the U3 to control the duty cycle of some sort of switch (transister, SSR, etc.), or perhaps you use an analog output on the U3 to control a motor controller or motor driver.  Try searching at labjack.comhttp://labjack.com/search using the term "motor control", and beyond that to get into more detail I suggest posting on our forum.

That is not a trivial task.  I suggest you start by reading some forum topics:

http://forums.labjack.com/index.php?showtopic=4263

http://forums.labjack.com/index.php?showtopic=4630

http://forums.labjack.com/index.php?showtopic=4856

http://forums.labjack.com/index.php?showtopic=5519

Then you want to work on what you are going to use to turn the motor on/off (3-phase relay or some sort of motor controller?) and selecting voltage and current sensors.  To get into more detail, post on the forums.

So the U6 will measure the signal from some light sensor, and then your software will perhaps use Windows API calls to adjust the brightness of the monitor?  The latter is not related to LabJack.  For the former, start a forum topic with a link to details about your light sensor.

How fast are you sampling the readings?  What are you using for software?  Typically you use software to provide timestamps.  I suggest you continue this discussion on the LabJack forums.

The things to consider are whether the signals can be measured by the U3 and how fast they need to be acquired.  I suggest using the forum to go in to more detail.

What sort of signal do you get from the sensors?  Voltage signal?  Max and min voltage?

The max sampling rate of the U3 is 50 ksamples/second.  That means you can scan 4 channels at 12.5 kscans/second.  At that scan rate you acquire frequencies up to 6.25 kHz, but anything higher than that will alias and appear as a lower frequency.

I would first recommend that you get started by opening our LabVIEW example programs to see how each of our provided VI blocks is used.  We have many provided VI's that let you open, configure, and control our devices.  Once you install the driver you should be able to open the VI's and they should run. Just in case you are having trouble finding our LabVIEW page:

http://labjack.com/support/ud/examples/labview

Once you have become comfortable with our device I would recommend using the google custom search bar on our site to look for more specifics on controlling servo motors with our devices.  We have many forum posts regarding stepper motor use with our devices:

http://labjack.com/search?cx=010374980958928572819%3Axqdgmh0dmmq&cof=FORID%3A11&query=stepper+motor&op=Search&form_build_id=form-4351bbb8c71994ba57d5fee7b97da396&form_token=5cf7601b329aef2ab2543b069b409a1d&form_id=google_cse_searchbox_form

It looks like the TE-0105 is a dimmer for low-voltage halogen lights.  Sounds like you want to control the dimmer by computer, so are wondering if the LabJack an go between the computer and dimmer to provide the interface.

We need more details about how the dimmer is controlled.  In Tridonic's "Transformers Overview" document, I see quick mention that communication with the dimmer is "switchDIM, DSI, DALI, or 1-10V switches".  Does the TE-0105 support 1 of these or all of these?  We need more details about these communication options.