LabVIEW Projects

1. LCR Grapher

   
   LabVIEW can be used to output a precise voltage that can be used to tell the Tectronics Signal generator which frequency to produce. Read the signal generator manual about external control of the signal.

   Use a LabVIEW-controlled signal generator to feed a signal into an LCR circuit. Read the input voltage V_p(t) and the output resistor voltage V_R(t). Determine the frequency f and the ratio V_P/V_R. Sweep through a large range of frequencies and have LabVIEW graph V_R/V_P versus f., i.e. graph the resonance curve. Repeat for the RC and RL circuits.

2. 3 Channel Scope

   
   In the first lab session, we saw the roundabout way an oscilloscope can be used to show the phase difference signal between a capacitor and a resistor. LabVIEW can do better. Consider the following circuit:

   

   Channel 1 will read V_R, 2 will give V_C + V_R, and 3 displays V_L + V_C + V_R = ε. Construct a VI to shows the signals from Ch1, Ch2, and Ch3 twice. When the user flips a switch have the VI change plot 2 to show V_C and plot 3 to show V_L. The VI will have to manipulate the signals to do this of course. Produce a series of outputs to show the effects of resonance on the output. Note inductors have a resistance; make sure R is much bigger than R_L.

   Bells and whistles: Have the VI also determine and show the phase angle in degrees for each plot.

3. TV Remote Control

   
   Part A Search the internet for info on TV remote control signals.

   Part B. Use LabVIEW and a light detector to display the signals generated by a TV remote control when a button is pressed. Have LabVIEW record the signal patterns.

   Part C. Design a front panel that looks like the remote. When the user presses a button, LabVIEW will send a saved signal to an infrared (IR) LED. Test your remote VI on the lab's TV.

4. RMS voltmeter

   
   Design a VI to sample an AC signal. Calculate and display V_DC, V_RMS, and V_AC-RMS. Note the AC signal can be sine, square, or trianglular.

5. Photogate Timer.

   
   Build a VI to read several Photogate timer signals. Determine the acceleration of a cart as it's flag passes through two gates separated by a distance L.

6. Thermocouple Thermometer and Newton's Law of Cooling

   
   Build a thermocouple. Build a VI to calibrate the signal (i.e. convert the voltage reading into a temperature). Investigate Newton's Law of Cooling. We have some material on this.

7. Index of Refraction of Air

   The Michelson Interferometer produces a pattern of bright and dark fringes. By counting the fringes as a function of the pressurre in a small tube, we can determine the index of refraction. The awkward job is counting the fringes. Design a VI to use a light detector to count fringes.