Article
ECG using a Sound Card
Medical signal processing on a PC
Is it possible to use a computer with an ordinary sound card to record an ECG (electrocardiogram) signal and measure someone’s pulse? This question has been researched in a university dissertation and answered convincingly in the positive. The heart monitor described here is the fruit of this work, and the software is available for free downloading.
Materials
Gerber file
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PCB
Component list
Resistors
R1,R2,R4,R6,R7,R19-22 = 10k
R3,R5 = 22k 1%
R8 = 47k
R9 = 42k2
R10,R11 = 3M3
R12 = 150k
R13 = 4k7
R14,R16 = 47k
R15 = 220
R17,R18 = 100
R23, R24 = 1M
P1 = 10k preset
Capacitors
C1,C2 = 27pF
C3,C10 = 1µF 63V, 5mm lead pitch (no electrolytic cap)
C4 = 100nF
C5-C8 = 100µF 16V radial
C9 = 1nF
C11 = 22pF
Semiconductors
IC1 = TL074 DIP14
IC2,IC4 = TS921 or TL071 DIP8
IC3 = IL300
Miscellaneous
Two wire links
Two 9-V PP3 batteries with connecting clips
Two DIL8 IC sockets
One DIL14 IC socket
PCB, order code 040479-1
PC software and source code, 040479-81
R1,R2,R4,R6,R7,R19-22 = 10k
R3,R5 = 22k 1%
R8 = 47k
R9 = 42k2
R10,R11 = 3M3
R12 = 150k
R13 = 4k7
R14,R16 = 47k
R15 = 220
R17,R18 = 100
R23, R24 = 1M
P1 = 10k preset
Capacitors
C1,C2 = 27pF
C3,C10 = 1µF 63V, 5mm lead pitch (no electrolytic cap)
C4 = 100nF
C5-C8 = 100µF 16V radial
C9 = 1nF
C11 = 22pF
Semiconductors
IC1 = TL074 DIP14
IC2,IC4 = TS921 or TL071 DIP8
IC3 = IL300
Miscellaneous
Two wire links
Two 9-V PP3 batteries with connecting clips
Two DIL8 IC sockets
One DIL14 IC socket
PCB, order code 040479-1
PC software and source code, 040479-81
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