aucustic comm. project presentation
TRANSCRIPT
ARDUINO MASTER-SLAVE ACOUSTIC COMMUNICATION SYSTEM
(4 points project presentation)
Presenter: Elia Linzky (317608313)
Advisor: Dr. Samuel Kosolapov
Introduction
Motivation:
Universality: Acoustics - an already existing ability to (but not limited to) all cellphones
Immediacy: Doesn’t require pairing. Ideal to transfer small amounts of data, fast.
Solution for private cases like in ships, planes, safe-rooms
Project goal: Examination of short range acoustic communication as a replacement for NFC (IR, WiFi etc.)
Introduction
Arduino development kit as a control unit
Common and cheap – 3$
Slow processor – 16Mhz
C programming language
Two communication methods: Morse Code, SKFK
Symbolic functions implementation: MC – Arithmetic device, SKFK – Temperature measurement
Goertzel Algorithm as frequency detector
Project details:
System Configuration & Behavior
MasterDevice
SlaveDevice I
SlaveDevice II
An optional configuration
Universal devices (M/S)
Device Basic Block Diagram
Control Unit
(Arduino MEGA)
Amplifier )OP(
BPF(Resonance Circuit)
LPF
ADC
Receiver TransmitterUSB to PC
Microphone
Temperature sensor
Speaker
Method I: Morse Code
f=1500[Hz], BR=250[dots per sec]
Easy to implement
Frequency independent
Noise sensitive
Needs additional hardware
Dictionary (from left to right)
0
5
Method I: Morse Code
Dot duration X 3 Dot durationDot duration
Signal Reception process:
Sampling
Control Unit
LPF
ADC
MicrophoneA
B
C
Voff=2.5V
Method II: SKFK
‘Pause’ – 1400Hz BR=25[signs per sec]
‘0’ – 1500Hz
‘1’ – 1600Hz
Decoded by Goertzel filter
0
5
0 PP 1 EOTSOT
Semi binary data transfer
Method II: SKFK
High noise resistance Low error rate
No additional hardware required
Transmitting to/receiving from multiple devices at once is possible
Long processing time
Limited to low frequencies
0
5
0 PP 1 EOTSOT
Electrical Scheme & Hardware Solutions
CU Amp.
BPF
LPF
ADC
Main Scheme:
Thanks for listening!
Additional Context
Neutralizing speaker’s inductive component
Boucherot cell:
Additional Context
Thermistor temperature calculation:
y = 1300.7e-0.038x
0
250
500
750
1000
1250
1500
1750
2000
2250
-20 -10 0 10 20 30 40 50 60 70 80
R[Ω
]
T[̊C]
Thermistor Resistance vs Temperature
Additional Context
Amplifier gain capacitor:
Additional Context
Microphone circuit:
Sensitivity
Additional ContextReceiver: RC LPF:
Vc(t)
charging
discharging
Dotlenght = 4 [mSec]
τ= RC = 0.5 [mSec] = Fast but stable enough
Additional Context
Resonation Xc=Xl
BPF:
Additional Context
Speaker:
Additional Context
Microphone: