Appendix D Ideas for Term Projects

Transcription

1 Appendix D Ideas for Term Projects Most of the labs in this course are activities directed by the instructor, and lack much opportunity for the student to exercise creativity. The purpose of a project is to give you that chance. A project is like research it is a task you can solve for yourself over a number of days (or even weeks) and which requires independent planning and thought. The more thought you put into a task the more you will no doubt learn about science and programming. Don t leave your project to the last minute. Level I There are Level I projects and Level II projects. A level I project is easier than a Level II project in that it involves some aspect of the instrumentation of science not recessarily requiring instrument control. If a least squares fit is requested you may use Excel or pro Fit. A level 1 project may also be selected with the instructor s consent from the end-of-chapter practice problems. 1. Standard Form I The color code for carbon composition resistors was given in Table 2-3. Write a G program to display the resistance of a resistor in standard form, i.e., as (resistance ± uncertainty) x unit. Your program should take four controls: one for each color band on the resistor. 2. Standard Form II Instruments are not yet provided with the firmware to display itheir measurements in standard form, viz., (measurement ± uncertainty) unit. Write a G program that takes a typical measurement from, say, a Radio Shack digital multimeter in a control and returns the result in an indicator in standard form. Use the specifications of the RS DMM as given in Table AA-4. Equip your VI with three additional controls: Function, Range and Value. 3. Formatting Number Strings A number returned by an instrument may be in standard floating point notation (1.23E 05) or in scientific format ( ). Write a program in G to take a number in any format and return the number as a string a.bc mu, where U stands for any unit and m stands for one of the common prefixes p pico 10 12, n nano 10 9, etc. etc. 4. Properties of a Sine wave The oscilloscope display of a sine wave signal is reproduced in figure AD-1. The data on which this display is based was saved using Oscar and is stored as the file sine.osc in LabVIEW Demos >> Data >> Oscar Files. Write a G program to input the data from this disk file and calculate the amplitude, peak-to-peak voltage, frequency and period of the wave. As a check on your work, compare your results with the results obtained by the oscilloscope and displayed in the measurement boxes in the figure. Figure AD-1. The display of an oscilloscope showing a sinewave. 5. Properties of a Triangle wave The oscilloscope display of a triangle wave signal is reproduced in figure AD-2. As in problem 3, the data on which the display is based is stored as the AD-1

2 Term Project Ideas file triangle.osc in LabVIEW Demos >> Data >> Oscar Files. Write a G program to input the data from the disk file and calculate the amplitude, peak-to-peak voltage, frequency and period of the wave. As a check on your work, you can compare your results with the results obtained by the oscilloscope and displayed in the measurement boxes in the figure. so forth you used. HINT: You might work at getting a screen save as is shown in Figure AD-4. You can then use the oscilloscope cursors to find the frequency. Figure AD-3. The display of an oscilloscope showing a square wave. Figure AD-2. The display of an oscilloscope showing a triangle wave. 6. Properties of a Square wave The oscilloscope display of a square wave signal is reproduced in figure AD-3. The data on which the display is based was saved using Oscar and is stored as the file square.osc in LabVIEW Demos >> Data >> Oscar Files. Write a G program to input the data from the disk file and calculate the amplitude, peak-to-peak voltage, frequency and period of the wave. As a check on your work, you can compare your results with the results calculated by the oscilloscope and displayed in the measurement boxes in the figure. 7. Blinking LED Module The Blinking LED Module sold by Radio Shack (part number ) produces red light from an LED that blinks at the rate of approximately once a second. (This module is designed to be placed on signboards in stores to attract the attention of customers.) Use this module with a silicon solar array and the Tek TDS210 digital oscilloscope to calculate the blink frequency. For full credit your solution must include a screen dump and a listing of the settings on the oscillo-scope, time base, and Figure AD-4. The signal from a Blinking LED module. 8. Instrument Waveform Preamble Instruments such as the Tek TDS210 digital oscilloscope output their data as I8 integers in binary or as comma-delimited ASCII values. These integers need to be converted to floatingpoint numbers by the controlling computer using calibration data contained in the waveform preamble. 9. Solar Array AD-2

3 Using a silicon solar array, a digital oscilloscope and the application Oscar, analyze the intensity of the light emitted by the fluorescent lights in the physics lab. HINT: You may expect that the light signal is comprised of more than one frequency component. You will need to use Oscar s FFT capability. For a review of FFTs see Appendix E. Term Project Ideas 10. Thermistor Using the control ThermistorData.vi write a G program to graph the data in an XY graph. Your program must include a dynamic readout of the cursor position. In other words, as the user moves the cursor on the graph your program should output the cursor position giving resistance and temperature. Level II Projects Level II projects will require more time to complete than Level I Projects. They involve an actual experiment and the writing and successful demonstration of a G program for collecting and graphing data. Unless otherwise indicated, any of the instruments described in this course may be used. A report must accompany the successful demonstration of the program. A level II project counts for 20% of the final mark in this course. 1. Charge Capacity of a Chemical Cell As described in Chapter 2 the charge capacity of a consumer-type chemical cell is given as a rating in milliampere-hours (ma-hr). Design and perform an experiment to determine the charge capacity of a typical cell. 2. Temperature Dependence of Internal Resistance The power a chemical cell or battery can deliver to a load is determined by the cell s design and internal resistance. The internal resistance is expected to be dependent in some way on temperature. Design and perform an experiment to study the temperature dependence of the internal resistance of a chemical cell. HINT: At each temperature selected you must be able to measure the emf ε of the cell and the current delivered to a load of fixed resistance (see figure). Rin ε precision resistor voltage measuring instrument Switch S in the figure might be a low-current DC switch activated by a logic signal from a DAQ card. The output voltage can be measured via one of the analog input lines on the DAQ card. 3. Calculating Heat Capacity with a Thermistor Design and perform an experiment to graph the rise in temperature of a known amount of water in response to the input of a known amount of heat. The heat may be transferred by a resistor of known resistance and the temperature may be measured with a thermistor. Determine from the graph the heat capacity of water. You may find the apparatus from the first year physics experiment Temperature and Heat to be useful in this project. 4. Monitoring Temperature with a Thermocouple The physics lab is supplied with a number of small electrically-powered ovens. Design and perform an experiment to examine the heating characteristics of such an oven, i.e., how the temperature varies with time once the power is applied and how stable is the maximum temperature reached. 5. Cooling I Hot coffee in a styrofoam cup might be expected to cool less rapidly when the top is on than when it is off. Design and perform an experiment using two temperature sensors to test this hypothesis. For full credit your project must include a data AD-3

4 Term Project Ideas analysis and the calculation of time constants. 6. Cooling II The heat absorbed by a metal surface is known to depend to some extent on the surface type, whether shiny or dull, white or black. Design and perform an experiment using a heat lamp shining with equal intensity on two metal containers of water, one painted white the other black. The two temperatures may be measured with two AD595 thermometers. 7. Controlling Oscilloscope Cursors The cursors on the Tek oscilloscope can be set as well as read programmatically. Devise an experiment involving a filter (RC circuit), the signal generator and oscilloscope to get two waveforms on the oscilloscope that differ significanly in phase. Write a G program to set the vertical cursors on zero crossings of the waveforms, read the cursors and thence determine the phase difference between the waveforms. 8. Measurement of Time Write and demonstrate a G program to perform the function of an electronic stopwatch using the DAQ card. A pushbutton switch with a debouncing circuit has been constructed for your use. This will require the connection of a 100 kω resistor and pushbutton switch as shown in the following circuit: 9. Digital Balance A modern digital balance is at heart a calibrated strain gauge. Design a procedure involving a G program to calibrate a sensor as a digital scale calibrated in kg. 10. Ohm s Law The IV characteristic of a carbon composition resistor (Ohm s Law) can be studied with the circuit drawn in the figure. can be read remotely. WARNING: You need to ensure that the power delivered to the resistor does not exceed the resistor s maximum power rating or the resistor may burn up. 11. IV Characteristic of a Solar Array Design and perform an experiment to graph and analyze the IV characteristic of a solar array. For this purpose you may use the apparatus that is used in the Solar Array experiment in the first year physics lab. Your project must involve the simultaneous reading of current and voltage across the load resistor. 12. IV Characteristic of an LED Design and perform an experiment to graph the IV characteristic of an LED which is forward biased. A similar caution applies as in the case of the resistor. 13. Temperature Dependence of V T The rectifier equation of a typical semiconductor diode is written I f = I r e V / V T ( 1 ) where V T = kt/e, k is Boltzmann s constant, T is the absolute temperature and e is the electronic charge. Design and perform an experiment to test the predicted temperature dependence of V T. 14. Temperature Dependence of Capacitance Much research is being done in an effort to find materials for making capacitors with a capacitance as independent of temperature as is possible. Design and perform an experiment to determine the temperature dependence of the capacitance of a capacitor over the range 0 to 100 C. 15. Photoresistance 16. Magnetic Field of a Coil The magnetic field strength at the centre of a solenoid of N turns of wire is given by The Agilent programmable power supply can be controlled via GPIB or serial interface such that the current and voltage delivered by the supply AD-4 Design and perform an experiment using the programmable power supply, a Hall effect sensor

5 and a standard solenoid to test this expression and determine the value of µ. 17. Transformer A transformer is designed to be more-or-less ideal over a fairly narrow range of frequency. Design an experiment to study the ideality/non-ideality of a common nominally 1:1 transformer. 18. Weather Station Data Write a G program to obtain via FTP a five-day dataset from the UTSC weather station and graph it. The project must include graphs of temperature, atmospheric pressure, relative humidity, wind speed and direction, precipitation and solar illumination. 19. Solar Illumination Maximum daily solar illumination (obtained at approximately local noon with a pyranometer as is used in the UTSC weather station) trends downward before the winter solstice and upwards after the solstice. Write a G program to extract via FTP and graph the solar illumination data from the UTSC weather station for one full year. Find a function for interpolating the average maximum solar illumination for any day of the year. 20. Instrument Calibration Because the Agilent 34401A DMM has 6-1/2 digits of precision it is commonly used to calibrate instruments having less precision. Design and perform an experiment to use the Agilent DMM to calibrate the RS DMM over the voltage range 0 to 5 volts. This project will involve controlling the RS DMM via the serial port and the Agilent DMM via a second serial port or GPIB. 21. Nyquist Frequency Design and perform an experiment to illustrate the effect of the Nyquist frequency. 22. Fourier Analysis I 23. Fourier Analysis II 24. Proximity Sensing Proximity sensing is of wide interest in the Life Sciences in monitoring the movement and behavior of small animals. Term Project Ideas 25. Temperature Control of Enclosures Controlling the temperature of an enclosure containing small animals is an important activity in the Life Sciences. This task can be simulated by controlling the temperature inside a popular cooler sold by Canadian Tire. 26. Heat Conduction in Water. Water is regarded as a good conductor of heat. In the process of heating a beaker of water on a hot surface like a hotplate it is of interest to know if the water heats uniformly throughout the volume of water or if the heat is conducted or convected from the bottom up. Set up an experiment as shown in the figure employing 4 Vernier Software standard temperature sensors at positions 4/5 H, 3/5 H, 2/5 H and 1/5 H, where H is the depth of the water. Connect the sensors to analog input channels 6, 4, 2, 0 of the DAQ beakout box. H B A C hot surface Write a G program to investigate the following questions: 1) Is the rate of temperature increase the same for sensors A, B, C and D? 2) How much time is required for the 4 sensors to reach the same temperature? 3) Does the data exhibit any evidence of thermalinduced currents in the beaker (i.e., is there any evidence of systematic variation in temperature?) D 27. AD-5

6 Term Project Ideas AD-6