* Tyrenny Hidy and Derek Russell EENG 383 – November 21, 2014

Tyrenny Hidy and Derek Russell
EENG 383 – November 21, 2014
This project has the following functions:
*Alarm is along the inside of a door with a break beam
*When the beam is broken, an alarm sounds.
*The user enters the code on the keypad, and the LEDs light
up as each number is pressed.
*If the code is correct, a fifth LED lights up, and a victory
song is played.
*Additional challenge given to us: Determine the optimum
distance for use of the break beam sensor
This project requires the use of:
*HCS12 Microcontroller board
*Break Beam Sensor System with IR receiver
and IR transmitter
*Additional protoboard
Pseudocode: Very basic premise of the design
Use delayusec code for song playing.
Initialize PT0 – PT3 as inputs, PT4 – PT6 as outputs (from
keypad), PT7 is an input from IR receiver
Initialize PM0-PM5 as outputs. PM4 is tied to the speaker;
PM0, PM1, PM2, PM3 and PM5 are LEDs.
If beam breaks, play alarm sound.
Keypad used to stop alarm sound.
If all four characters are correct, light green LED, play
victory song.
The team was asked by Dr. Hoff to investigate
the challenges the class had with the break
beam sensor.
Possible reasons and solutions for the challenges:
Oversaturation of the signal.
The frequency is incorrect.
The sensor was being held much too close.
Move the sensor further away.
What is the minimum distance?
What is the maximum distance?