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Digital Impulse Relay
Introduction In the first
place, a relay is like a switch to a coil
assembly. This switch is activated when
electricity is applied to the coil. With a
common relay, the electricity must be
continuously applied to the coil to maintain the
contacts, but the impulse relay "remembers" and
only requires a momentary application of
electricity. Stated differently, apply pulse of
electricity to the coil to turn on the relay
contacts, apply another pulse of electricity to
turn off the relay contacts. So, impulse
relay use it for to turn on a lamp with
pushbuttons and not toggle switches. What is
really neat is connecting several momentary
pushbuttons in parallel and placing them in
different locations. I can turn on the lamp in
one room, and turn it off from a different room,
because it was the relay that was providing
electricity to the lamp, not the switch.
Description
A
digital impulse relay
is a electronic circuit that mimics perfect
the all functions of a impulse relay
with ratchet mechanism:
the first press to the button turns the relay on and
the second press turns it off, and
relay in the circuit
operating room illuminates. Particularity of
this circuit is that it can be used in a centralized
system for home automation. Another advantage is
lower price compared with that of the
impulse relay with
ratchet mechanism. Digital impulse relay is
immune to electrical noise, connection between
buttons and circuit can be achieved with unshielded
cable and any length.
Schematic
This circuit is
operating the
room illuminates.
The
basic component
of the circuit is
a IC1 (CD4017). Push buttons
room are connected by normally wired to the circuit.
All circuit is separately by optocoupler, which
means that the circuit is immune to electrical noise
that can come on cable that connects with push
buttons.
First any button push put to
GND the optocoupler IN.
The output signal from
optocoupler
is amplified by transistor
Q1 (BC557) together by C1, R3, R4 circuit.
The
amplified signal is
attack
to clock pin 14 of decade counter
IC1 (CD4017),
the counter
advances by 1, pin 2 goes high and relay is ON.
Transistor Q2 (2N2222) connected to pin 2 of IC1
drives 12V relay. Diode 1N4004 (D1) acts as a
freewheeling diode. LED1
indicate the ON/OFF status.
Second any button press, the
IC1
advances by 1, pin 2 goes low, relay is OFF, and pin
4 goes high. If we connect by diode D2, pin 4 to
Reset pin of CD4017, the counter is going back to
the initial condition, and is ready to get another
button
press, to turn the relay ON.
The C2 - R6 component keep the Reset pin to +12V,
when the circuit is
powering, until
the C2 loaded at 12V.
From transistor
Q2 colector is IN/OUT for use in to microcontroller
system (GSM remote control, WEB control, etc.). When
use as IN, microcontroller system can put to GND Q2
colector, and relay is ON. Or the colector is use as
OUT, signal obtained say the microcontroller system,
if the relay is ON or OFF.
The power supply for the
circuit is DC 12V. In standby, when relay is OFF,
digital impulse
relay consume 0V. Otherwise,
when relay is ON, consume
depend of 12V relay current.
Installation
Parts List
IC1 - CD4017
PCB
Photos
Video
Download
Q1 - BC557
Q2 - 2N2222
OK1 - PC817 (optocoupler)
D1 - 1N4004
D2 - 1N4148
R1 - 3 K
R2 - 100 K
R3 - 1 K
R4 - 10 K
R5 - 1 K
R6 - 100 K
R7 - 1 K
C1 - 100 nF
C2 - 100 nF
С3 - 1 uF/25V
С4 - 1 uF/25V
С5 - 1 uF/25V
С6 - 1 uF/25V
LED1 - led diode
K1 - 12V relay
Download PCB and Schematic
Eagle files
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