Sensors, Actuators and Computer Interfacing Labs with NI LabVIEW

University: University of California, Santa Barbara

Department: Mechanical Engineering

Course: ME 104 - Sensors, Actuators and Computer Interfacing

Below is a list of hardware-based exercises and labs that can be used to explore controls and mechatronics concepts. Click here to visit the current course website. 

Lab 1 - Introduction to LabVIEW

In this laboratory, students learn how to use the National Instruments LabVIEW development environment, which is based on the graphical programming language G. They then write a LabVIEW program to acquire, display, and save an external voltage signal. As an extra credit exercise, students may investigate the effects of undersampling.

Lab 2 - Hall Effect Sensors

In this laboratory, students learn how to use a Hall Effect sensor to detect the presence of a magnetic field due to a permanent magnet. Then, in a simulation of an attendance counter at a turnstile, they write a NI LabVIEW program to count the number of times that a magnet is moved past the Hall sensor. Finally, they write a program to compute and display the total (cumulative) duration of low pulses. As an extra credit exercise, students may write a program to count and display the number of long low pulses, that is, low pulses that are at least 200 ms in duration.

Lab 3 - Strain Gage Sensors

In this laboratory, students build an analog circuit that will enable them to use a strain gage to measure the deflection of a metal ruler. They then add a noninverting op-amp to amplify the voltage output from the circuit and an analog low-pass filter to remove voltage fluctuations caused by high-frequency noise. As an extra credit exercise, students may write a NI LabVIEW program to compute the power spectrum of the output from the strain gage circuit before and after the low-pass filter.

Lab 4 - Open-Loop Analog Control of a DC Motor

In this laboratory, students write a NI LabVIEW program to drive a DC motor using an analog voltage signal. They also learn how to measure and view both angular velocity and angular position feedback signals from the motor. The DC motor is part of the MS15 DC Motor Control Module. They can control the angular velocity of the motor using either an analog voltage signal or a pulse-width modulated (PWM) digital signal. This laboratory uses only analog signals.

Lab 5 - Frequency Response

In this laboratory, students build a NI LabVIEW VI to obtain the frequency response (magnitude and phase) of an external system. They then use this VI to obtain the frequency response of an analog low-pass filter, an analog high-pass filter, an analog band-pass filter, and a DC motor.

Lab 6 - Closed-Loop Analog Control of DC Motor Velocity

In this laboratory, students build analog circuits to implement proportional (P), integral (I), and proportional-integral (PI) control of a DC motor using NI LabVIEW. The ultimate goal is to control the DC motor so that the velocity (voltage) output VOUT is equal to a (desired) reference (voltage) input r.

For this laboratory, they power LMC6484 op-amp chips using V+ = 5 V and V- = -5 V. An MC7905 negative voltage regulator is used to convert the -12 V signal from the DC power supply to a -5 V signal for the op-amp.

Lab 7 - Stepper Motors

In this laboratory, students write a NI LabVIEW VI for generating digital TTL signals that they can use to generate the stepping sequence for a four-phase unipolar stepper motor. They then use a function generator and an analog drive circuit to control the rate of rotation of a unipolar stepper motor in full-step mode. As an extra credit exercise, students may build LabVIEW VIs for controlling the rotation of the stepper motor in full-step mode.

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