Enhancing Class Participation Device: Senior Design at Univ. of Illinois, Urbana-Champaign, Study Guides, Projects, Research of Electrical and Electronics Engineering

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University of Illinois, Urbana-Champaign

ECE445 – Senior Design Lab

Spring 2006

Design Review:

Improved Class Participation Input Device

Ching Man Hui

Debi Misra

TA: Hyesun Park

Improved Class Participation Input Device I. Introduction Recently, several professors at the University of Illinois, Urbana-Champaign (UIUC) began to enforce student attendance and participation by implementing a wireless input device system in their classes. It is a simple concept: professors ask a question, the students then pick a choice using their input devices and the answer is recorded. If a student answers a question correctly, he or she receives a point for participation. However, the actual implementation of this system is not that simple. Currently, in a certain course held at UIUC, an input device by Turning Technologies, called Response Card RF, is used. The keypad contains 12 buttons labeled digits 0-9 (A-J), “Go” and “?”. There is also one LED on the input device to signal successful transmission. What inspired us to improve the class participation input device was the tremendous confusion during the first few lectures of the semester. Due to the lack of a display on the input device, students were not able to confirm that their input device:

1. worked properly,
2. was on the correct channel, and
3. sent the desired answer. Students were also unable to confirm that their answer was received and recorded. Our project aims to improve the current class participation input device by creating a more user-friendly version. We believe that the improved input device will benefit students and ease their anxiousness in submitting answers. It will also benefit professors by not wasting valuable class time to set up the system and ensure that each student’s input device works properly. Objectives: In order to demonstrate the effectiveness of our improved input device, we will create the input device and the CPU. We will use 2 sets of the HP series transmitters/receivers to complete this project. One set will be used to send data from the input device to the CPU. One set will be used to send confirmation from the CPU to the input device. For the input device, we will use 2 LEDs: an LED to confirm the signal has been sent and an LED to confirm the answer has been received and recorded. We will also add an LCD display to the input device to confirm channel and answer to be sent.

Input Device CPU Receiver Transmitter Recorder Transmitter

LCD

Receiver

LED LED

PIC

Number Pad RF RF Power Supply

Block Descriptions: Our project contains two units: an input device and a CPU. Input Device The input device will contain 7 modules: a PIC, a number pad, an LCD, 2 LED’s, a transmitter, and a receiver. This wireless device is used by students to enter, confirm and send an answer, as well as to receive a signal for answer processing confirmation. PIC This module is the core of the input device and is linked to each of the 6 modules using a microcontroller on a PCB. When students input their answers using the number pad, this module registers the answer and displays it onto the LCD. After students confirm the answer, the answer will be sent to the CPU by the transmitter, and LED A will illuminate to confirm that the answer has been sent. Once the CPU has recorded the answer, the receiver will obtain a signal to confirm that the answer has been processed and recorded. The PIC registers this signal and the LED B will illuminate to acknowledge the student of the confirmation. Number Pad Students will use this module to input their answers by pressing the buttons for digits 0-9 or letters A-D. Students will also use the number pad to confirm their answers by pressing the asterisk button or to request to re-enter their answers by pressing the pound button. LCD This module will display the channel of the input device and the answer that a student has entered by the use of the number pad. LED A This module will illuminate when the answer is confirmed and ready to send. Transmitter The transmitter sends a signal (the answer) to the receiver of the CPU. Receiver The receiver obtains a signal from the transmitter of the CPU to acknowledge that the answer has been processed and recorded. Then the receiver sends a signal to the PIC to illuminate LED B. LED B This module will illuminate after the PIC registers the signal obtained by the receiver.

Input Device Schematic:

CPU Schematic:

Performance Requirements: Our improved input device should meet the following performance requirements:  Illumination of LEDs to confirm data transmission  Less than 2 seconds response time for LEDs to illuminate  200 ft transmitting range The input device will be simulated in a classroom environment. The student will use the input device to submit their answers, and the professor will use the CPU unit to record students’ answers. Improving feedback is one of our main goals, and the LEDs will signal successful data transmission to the students. The response time should be less than 2 seconds to minimize confusion and anxiousness of students. A typical classroom would be no longer than 200ft, thus the input device should meet the 200ft transmitting range. III. Verification Testing Procedures: As we complete various parts of the design, we will test each component separately to validate that it functions on its own. The testing procedures for each component are described below: LCD We have powered the LCD to ensure it would light up. We will adjust and send the 8 bits of data from the PIC according to the character font codes on the data sheet to ensure that digits 0-9 and letters A-D can be properly displayed. Later, we will verify that the LCD is properly displaying the channel, as well as the selected answer. LEDs We have tested that the LEDs properly illuminate when voltage is high. We will test LED A to ensure that it illuminates after an answer has been confirmed and ready to be sent. We will also test LED B to ensure that it illuminates after the signal is received and recorded by the CPU. CPU If the transmitters and receivers are working properly, then the CPU should be able to record the answer correctly as well. We will test the CPU by monitoring the recorded answers. Transmitters/receivers First, we will test to ensure that we have set up the transmitters and receivers correctly and that the signals are being sent and received as desired by inputting a

square wave (from a function generator) and recording the output on the oscilloscope. We tested the RF network at a distance of 22 feet. Our results confirmed our set- up and the functionality of transmitters/receivers: DIAGRAM A This is the inputted square wave sent form the function generator to the transmitter on the input device. The top line represents a second channel that was not connected for this particular test. DIAGRAM B This is the output of the receiver on the CPU side. Once this works, we will test the different channels for the least noise. Upon programming the PIC, we will test the range for the input device.

After each component passes its function test, we will then test the input device system by running through the entire process. We will use the input device to enter the answer. This will re-confirm proper operation of the number pad and the LCD. We will then send the answer after the LCD displays an answer confirmation. When the answer is sent, the correct operation of the LEDs and the transmitters/receivers will be verified. Our goal is for the user to input, confirm, and send an answer and for the CPU to properly record the user’s input in less than 2 seconds. Our range will be tested through our tolerance analysis below. In the end, we will simulate a classroom to test and verify that our input device system meets our goal and performance requirements. A successful trial would indicate that our PIC functions perfectly as well. Tolerance Analysis: Our input device will rely heavily on the wireless RF networks for both answer submissions and feedback purposes. An important factor in a successful RF network is the distance between the CPU and the input device. One of our performance requirements is 200 ft range between the input device and the CPU. We will measure the effectiveness of our input device at various distances in a classroom. From our results we will analyze and determine the maximum distance between the input device and the CPU that still allows for proper operation. IEEE Code of Ethics We are new partners for this project, so our strengths and weaknesses regarding equipment usage and EE knowledge differ. In accordance to the IEEE Code of Ethics, we will work together as a team and support each other in making our project successful. We will admit our mistakes and seek help and criticism of our work. We will also credit contributions to others who have helped us. One of our goals for this project is to learn additional technical skills and technology applications. Finally, since our input device is already on the market, we will ensure that our input device is unique.

IV. Cost and Schedule Cost Analysis: Labor Ching Man Hui ($50/hr) x 2.5 x 100 hrs $12, Debi Misra ($50/hr) x 2.5 x 100 hrs $12, Estimated Labor Total $25, Equipment Description Part Number Quantity Price ea. Total Price Wireless RF Transmitters Linx HP Series 2 $24.10 $48. Wireless RF Receivers Linx HP Series 2 $32.20 $64. Antennas/cables 4 $4.61 $18. 32 characters *2 lines LCD Shelly 1 $5.00 $5. LEDs 2 $.20 $. 6” by 9” Protoboard 2 $100 $ Number pad 96BB2-006-R 1 $12.87 $12. Microcontroller PIC16F877A 1 $9.95 $9. Driver/Receiver MAX232 2 $1.55 $3. Serial Port Cable RS232 1 $12 $ 20MHz Crystal Oscillator 1 $1.50 $1. Miscellaneous (wires, resistors, capacitors, soldering materials, etc) $ Estimated Equipment Total $385. Estimated Total Costs (Labor + Parts) $25,385. Parts Status: We had received many of our parts through the TA and the Parts Shop. We have all our parts except for the RS232 cable.