EE 200 Problem Set 10 Cover Sheet Spring 2014Last Name (Print):First Name (Print):ID number (Last 4 digits):Section:Submission deadlines:• Each EE 200 student must complete the circuits in problem 37 prior to attending Laboratory #20. At thebeginning of Laboratory #20, each student must show the completed circuit to the instructor to receive agrade for problem 37.• Demonstrate compl etion of problem 3 8 during the evening lab oratory session on either Monday March 31 orTuesday April 1 from 6:30 pm to 8:30 pm in 302 EE West. You must sign up for a ten minute slot usingSignUpGenius. You will receive an emai l message via your Penn State email address when the sign up sheet isavailable online at SignUpGenius. Slots are filled on a first-come, first-served basis.• Turn in the written solutions for problems 39 and 40 by 4:00 pm on Tuesday April 1 in the homework slotoutside 121 EE East.Problem Weight Score37 2038 3039 2540 25Total 100Problem 37: (20 points)A goal of Laboratory #20 i s to read the angular displacement of a mechanical encoder using the dsPIC33EP64MC502microcontroller using the C programming language and the myDAQ usi ng the LabVIEW programming environment.You will also realize a LED dimmer system that utilizes the mechanical encoder a long with the microcontroller.Eve ry EE 200 student must construct the circuits in Figures 1 and 2 and bring them to Laboratory #20. Detailsfor completing the microcontroller interface circuit in Figure 1 are available in Problem Set 7 Problem 25. To avoidcontact bounce producing undesirable changes in the encoder count, the circuit in Figure 2 incorporates two 0.01 µFcapacitors, that in conjunction with the 27 kΩ resistors, form low-pass filters that attenuate the multiple pulsesresulting from contact bounce. The 0.01 µF capacitors are not contained in th e EE 200 Component Kitand will be distributed by t he instructor at the start of Laboratory #20. Identify the terminals A, B, andC of the mechanical encoder using the specification sheet, Bourns encoder.pdf, included with Problem Set 10.Figure 1: Basic connections for all EE 20 0 microcontroller exercises.Figure 2: Additional circuit connections required for Laboratory #20.Problem 38: (30 points)Each EE 200 student must realize the finite state machine for robot naviga tion introduced in Problem Set 3 Problem10 using the dsPIC33EP64MC5 02 microcontroller, and demonstrate their circuit to the laboratory instructor duringthe grading session on either Monday March 31 or Tuesday April 1 from 6:30 pm to 8:30 pm in 302 EE West. Toreceive full credit, your system must comply with the following specifications:1. Use the signal assignments in Table 2.Signal Designation Signal Description Microcontroller I/O designation Pin NumberMLleft mo tor dri ve RB15 26MRright motor drive RB14 25SLleft sensor signal RA0 2SRright sensor signal RA1 3SBback sensor RPI32 4Table 1: The myDAQ Digital I/O assignments.2. Connect the input swi tches and output LEDs as indicated in Figure 3. Note that pressing a given button setsthe signal to a logic hi gh state, while the corresponding logic level at the microcontroller peripheral I/O pinconnector is at logic l ow state. For example, when the user presses the button SL, the value of SLbecomesone while the corresponding logic level at pin 2 (RAO) i s zero.Figure 3: Microcontroller connections to i nput switches and o utput LEDs.3. Implement the FSM in C using Exercise 3 in Laboratory #16 as a guide.4. R ealize the finite state machine using two nested switch statements within a while-loop as discussed in Labo-ratory #16. The inner switch statement acts on the values of the sensor inputs SLand SR. Simplify the codefor the inner switch statement by using a single integer variable, called input, to represent SLand SRas shownin Table 2.Input IntegerSRSL0SRSL1SRSL2SRSL3Table 2: Representation of front sensor inputs using an integer.5. R ead the front sensors SLand SRonce per second, and appropriately up date the state and outputs.6. Implement an a synchronous reset usi ng interrupt I NT1. Pressing the button SBmust trigger an interrupt thatsets outputs MLand MRto one and the state to S1.During the project demonstration, the instructor will award points using the following criteria.1. (5 points) Each tactile switch and LED must be labeled with the corresponding signal, SL, SR, SB, ML, andMR. Use a post-it note or, alternatively, tape a piece of paper to the wiring connecting the switch or LEDwith the appropriate signal label. Credit for pa rt 1 is awarded only if the work for part 2 is compl ete.2. (4 points) Show the C code to the instructor and demonstrate that you can compile and down load the codeto the micro controller.3. (5 points) Show that the C code uses two nested switch statements to realize the finite state machine, and tha tthe inner switch statement acts on an integer represnting the values of the sensor inputs SLand SRas definedin Table 2.4. (8 points) Demonstrate that pressing the back sensor button triggers an interrupt that returns the system tostate S1 and appropriately sets the o utputs.5. (8 points) Demonstrate that system responds correctly to the inputs SLand SR.Problem 39: (25 points)It is sometimes necessary to regulate the temperature of precision instrumentation as temperature fluctuations causesmall drifts in bias currents that can corrupt the measurement of small signals. As an example, the integratingpreamplifier in Figure 4 uses feedback to ma intain the temperature of the measurement circuit at 100◦F, despitevariations in ambient room temperature. A low-noise preampli fier along wi th an integrator realized using an opera-tional amplifier are contained within the shielded box mounted on the copper plate. The copper plate is heated bya set of power resistors affixed to the plate. A feedback system moni tors the plate temperature using a thermistorand automatically regulates the current flow through the heater resistors to maintain the copper plate temperatureat a desired value.Figure 4: Integrated preamplifier using temperature regulation.1. (10 points) Suppose the current through the heater i s controlled by varying a series control resistance Rcshownin Figure 5. The independent voltage source provides a constant value of 12 V while the heater consists ofthree 20 Ω, 25 W power resistors connected in parallel.(a) (4 points) Determine the value of Rcso that the power Pheaterdissipated by the heater is 10 W.(b) (2 points)