 PIC16F84A
The electric wave which was made with
oscillato is controlled by this PIC.
A control code
is made with the software of PIC16F84A. The control code can be easily
changed if changing software.
It uses RA0 and RA1
for the input to choose a control code and it is using RA4 for the control
of the oscillation circuit.
Transistor for high frequency oscillation and
high frequency power amplification ( 2SC1906 )
2SC1906 is used for the
high-frequency oscillator and the power amplification.
The transistor with high fT (the maximum cutoff
frequency) is needed because it handles a high frequency. The
fT of 2SC1906 is 600MHz-1000MHz. Because it handles an about
80-MHz frequency at the circuit this time, there is a lot of
leeway.
3 terminal regulator ( 78L05
)
The power of this transmitter is a
+9V battery.
3 terminal regulator is used to make
the power (+5V) of PIC from +9V power.
A 100mA type
is used.
Resonator
This is the oscillation
device to make the clock of PIC. A ceramic vibrator and capacitors are
incorporated.
The clock frequency this time is 4
MHz. It is possible to make do the operation of PIC16F84A with the a
maximum of 20MHz clock.
Diode
This is the diode to control the input of PIC
by the switch operation. This time, I used diodes for the rectification.
However, because few flowing electric currents occur, the switching diode
(Io=120mA) such as 1S588 and so on can be used.
Coil
The coil to be using this
time is using the one to have wound a tin plating wire with 0.6mm diameter
around the stick (the screwdriver) with 4.6mm diameter seven times. I make
a tap (the node of the power) at the position of 4.5 turns from the side
which connects with the collector.
You can use a
coil bobbin with the core, too.
IC socket
This is an 18 pins socket
for PIC16F84A.
I used a round hole type but you can
use a board type, too.
Resistor
As for the resistor,
all 1/8W are used.
Ceramic capacitor
Ceramic capacitors with good high
frequency characteristic are used for the resonance circuit of the
oscillator.
Multilayer ceramic
capacitor
The unnecessary high frequency which
influences circuit operation is bypassed with these
capacitors.
This capacitor has a large capacity
comparatively with 10000pF but it is small.
Printed board
The universal printed board which
was cut in the needed size is used.
When handling a
high frequency circuit, the length of the wiring influences the operation
of the circuit. Because it is, actually, it had better use a printed
board.
Stud
These studs are used to
fix a printed board on the case.
Battery
It used a 9V dry
battery.
This dry battery is called 006P in Japan.
Maybe this dry battery is called as 1604(NEDA) or 6F22(IEC).
Dry battery plug
The pole of the 9V dry battery
connects with the special plug.
Switch
These switchs combine the
power switch and the selection of the control code. These are a non lock
type. Only while pushing a switch, the electric wave which was controlled
with the code is emitted.
Case
I housed a transmitter in the
case which was made by bending acrylic board.
Cushion for battery
A sponge was used to fix a battery
in the case. I used the sponge of 6 mm of thickness.
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