Download Sunrise Alarm Clock for the Hearing Impaired

Sunrise Alarm Clock for the
Hearing Impaired
Jim Follum
Senior Honors Project
Motivation
• Waking to sunlight is more natural and gradual
• Applications to assistive technology for the
hearing impaired became apparent
• Current alarm clocks for the hearing impaired
– Flashing lights
– Bed vibrators
– Adjustable frequency, high decibel audio alarms
• Project goal: prototype a more effective and
pleasant alarm clock for the hearing impaired
2
Approach
• Three alarm system
– Visual: sunrise mimicked using bedside lamp
– Physical: vibrating wristbands
– Audio: buzzers with two pitch options
• Two user functionality
3
Implementation: Visual Alarm
• Lamps controlled through
standard receptacle
• Supplied with pulse width
modulated (PWM) direct
current (DC) voltage
source
– Frequency: 122 Hz
surpasses the eye’s ability
to perceive flicker
– Duty cycle: adjusted to
control light output
Pulse Width Modulation (PWM)
10% Duty Cycle
30% Duty Cycle
50% Duty Cycle
Time
4
Implementation: AC to DC
Direct Current (DC) Signal
Alternating Current (AC) Signal
200
200
150
150
100
50
Rectifier
&
Capacitor
0
-50
-100
Voltage (V)
Voltage (V)
100
50
0
-50
-100
-150
-150
-200
0
5
10
15
20
Time (ms)
25
30
-200
0
5
10
15
20
25
30
Time (ms)
5
Implementation: Switching
6
Implementation: Opto-isolation
+
=
7
Implementation: Visual Alarm Circuitry
LR645N5
IN
120 VAC
L1
RS504-G
C4
470uF
Rect
From uC
F1
1A
Q1
STP30NF20
IRF620
6N137
R7
P1
P8
P2
P7
47 Optocoupler3
P3
P4
P6
P5
L2
R3
1k
78L05
OUT
IN
COM
F2
1A
OUT
COM
C6
1uF
C11
.1uF
Q2
STP30NF20
IRF620
R6
1k
C8
.1uF
6N137
R8
47
P1
P8
Optocoupler3
P2
P7
P3
P6
P4
P5
R4
1k
R5
1k
C7
.1uF
• Full wave bridge rectification with smoothing capacitor for 170
VDC voltage supply
• Power MOSFETs for switching action
• High input voltage regulator in tandem with 5 VDC regulator
for MOSFET switch voltage
• Opto-isolation for circuit protection
8
Implementation: Physical Alarm
• 3 VDC vibrating motors provide stimulation
• Housed in athletic wristband
• Controlled by driving BJT transistors with
PWM signal
• Pulse along with audio alarm
• Physically connected to alarm body
9
Implementation: Audio Alarm
• Two Piezo buzzers
provide stimulation
– 2.7 kHz, 75 dB maximum
– 3.5 kHz, 86 dB maximum
• Potentiometers provide
volume control
• Controlled
simultaneously with
physical alarm
10
Results
• Audio and physical alarms
fully functional
• One visual alarm
operational
– Effective at waking user
• Time keeping accuracy
very poor
– Delayed by approximately
2 seconds every minute
– External oscillator began
interfering with LCD after
damage to circuit board
occurred during testing
11
Future Work and Alternatives
• Visual alarm
– AC phase modulation to dim bulb
– Allow use of compact fluorescent and LED bulbs
– Remove user’s access to lamp control signal
• Physical alarm
– Wireless wristbands
– Conversion to bed vibrator
• Audio alarm
– Spectrum pitch control
– Improved ability to match hearing configurations
12
Acknowledgement
• Funding for this project was provided by the
National Science Foundation’s Biomedical
Engineering - Research to Aid Persons with
Disabilities program
• Jenny Catchpole
• Faculty of the Electrical and Computer
Engineering Department at the University of
Wyoming
• Dr. Barrett, Dr. Whitman, Dr. Legowski, Dr.
Muknahallipatna, Vic Bershinsky, and George
Janack
13
Questions?
14
Audio and Physical Alarm Circuitry
12V
R2
10k 40%
10k 40%
BZL1
R14
10k
BZL2
-
Q3
MPS2222A
+
BZH2
-
R12
10k
+
M1
BZH1
S2
M2
+
+
S1
From uC
R13
120
R11
120
Q4
MPS2222A
15