Computer Alarm System

EECS 373 Fall 2004

Designed and Created by:
Erin Wakefield and Alfonso Martinez

*Brief Project Description:

Our design is computer alarm system that uses a distance sensor to be set-off, has PIN protected settings, displays the alarm status and menus on the LCD, and can be set to either audible or silent alarms.

Description of I/O Components:

LCD:
 Displays alarm status (on/off and audible/silent) and menus to make changes.
Buzzer:
sounds if alarm is set off by the distance sensor and is set to audible
LEDs:
Flash if alarm is set off by the distance sensor and is set to silent
Keypad:
Used to enter in PIN (needed to change settings), and make menu choices as displayed on the LCD
Distance sensor:
Sets off alarm if someone comes within so many feet

Problems Encountered:


*********Most of the problems we had dealt with hardware. When we first began using the keypad and LCD display together, the different signals were causing so much induction that we couldn’t get them to work at the same time. We also had many issues with the keypad itself, and for some reason could not get more than three columns working at the same time.
*********Xilinx itself was the cause of a lot of our problems. Some of our macros kept being randomly deleted from our project, and for awhile we could not get the ADC macro to save after we corrected it as described in lab 8. This caused a lot of frustration and irritation because it made it impossible to get any real work done.
*********We also experienced many problems with coupling and induction. Since our I/O devices were so numerous and close together, a lot of our signals irritated the other devices. We solved some of this problem by using thicker wires, physically separating wires, increasing time between reads and writes to allow signals to settle down, and adding ground lines and resisters – particularly to the keypad.
*********In addition, another problem we had was running out of pins. After we had attached the LCD and keypad, we only had two pins left for our three LEDS and buzzer. We solved this problem by adding the decoder, thus turning our two signals into four. This was a simple and effective fix.
*********Finally, our last and most awful problem was when the whole project stopped working altogether, except for the LCD and a very tempermental keypad. Of course this occurred the night before the demo, but we showed what we had and did our best.

*For more details see the Complete Project Report