| RPC2 -
A
Basic Features:
1. Uses MT8870
2. Screw type Output Terminals
3. May be powered from terminals or 2.1mm Jack
This PIC16F84a based repeater
(DTMF) controller
is very
simple
&
economical
to build.
It also
gives you hand-on
experience
of using
&
programming
PIC Micro
controllers. Controller measures 10cm
X 6 CM and may be housed in your repeater project enclosure
Controller
here is
based on a
design idea from
Dave
Robinson/WW2R
who has
provided
necessary
software
&
hardware
information
on this
controller.
Design of
this
Controller
is based on MT8870 DTMF
receiver,
a
Microchip
16F84A
Micro-Controller
and
an
ULN2803A relay
driver .
Controller has 8
OC outputs
to drive 8
relays.
Outputs
are
available
at 12pin
header
socket or screw-in terminal blocj where a
ribbon
cable may
be
connected.
In
addition
to 8 OC
outputs,
header/terminal
socket
also
provides
12V,
Ground
& 5V
(for
pull-ups
only).
Controller is without
relays
& is designed to be accommodated within an existing
project, where DTMF
control is
required. It
will
drive
5/12V
relays of
any type, without
problems.
Firmware
for PIC is
available
here for
download
in .ASM
file
with
password
1234 which
may be
changed at
the time
of
programming
the PIC. This firmware was tested & controller worked
perfectly without missing any command.
Another version of Firmware which is supposed
to "remember" last status of relay after a power failure, is also available but
I have not tested it yet.
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