Fig. 1
Schematic diagram
Fig. 2
Arrangement of components on the PCB
2
The circuit must be assembled on a single-sided PCB
as shown in Figure 2. Start by soldering resistors and
other small components onto the board and finish by
fitting electrolytic capacitors, transistors and screw
connectors
.
Microphone can be soldered directly to
the
angled goldpin strip. Device assembled flawlessly,
using functioning components, will work as soon as
the supply voltage is switched on.
Mounting and start-up
MEGA8-P
330R
330R
330R
10K
10K
10K
+12V
GND
10K
+5V
LM358N
LM358N
2.2K
GND
+5V
1uF
1M
33K
GND
+5V
220K
22K
GND
10p
390K
33K
+5V
GND
33K
GND
100K
10p
330R
1n
GND
1uF
GND
7805
+5V
+12V
GND
GND
10K
+5V
GND
GND
GND
GND GND
+12V
LINE
IN
+12V
PWR
GND
OUT1
GND
OUT2
OUT3
PB5(SCK)
19
PB7(XTAL2/TOSC2)
10
PB6(XTAL1/TOSC1)
9
GND
8
VCC
7
GND
22
AREF
21
AVCC
20
PB4(MISO)
18
PB3(MOSI/OC2)
17
PB2(SS/OC1B)
16
PB1(OC1A)
14
PB0(ICP)
15
PD7(AIN1)
13
PD6(AIN0)
12
PD5(T1)
11
PD4(XCK/T0)
6
PD3(INT1)
5
PD2(INT0)
4
PD1(TXD)
3
PD0(RXD)
2
PC5(ADC5/SCL)
28
PC4(ADC4/SDA)
27
PC3(ADC3)
26
PC2(ADC2)
25
PC1(ADC1)
24
PC0(ADC0)
23
PC6(/RESET)
1
US1
T1
T2
T3
R1
R2
R3
R4
R5
R6
R7
2
3
1
US2A
6
5
7
US2B
1
2
JP1
R8
C1
R9
R10
R11
R12
C2
C3
R13
R14
R15
R16
C4
R17
C5
C6
GND
VI
1
3
VO
2
US3
C7
C8
C9
C10
3
1
S1
R18
SEL
1
2
3
L1
C11
C12
D1
+
+
+
