|
A few designs
for remote control switches, using VG40T and VG40R remote control
pair, are shown here.
The miniature transmitter module shown in Fig. 1, which just
measures 34 mm x 29 mm x 10 mm, can be used to operate all remote
control receiver-cum-switch combinations described in this
project. A compact 9-volt PP3 battery can be used with the
transmitter. It can transmit signals up to 15 metres without any
aerial. The operating frequency of the transmitter is 300 MHz. The
following circuits, using VG40R remote control receiver module
measuring 45 mm x 21 mm x 13 mm, can be used to:
(a) activate a relay momentarily,
(b) activate a relay for a preset period,
(c) switch on and switch off a load.
To activate a relay momentarily (see Fig. 2), the switch on the
transmitter unit is pressed, and so a positive voltage is obtained
at output pin of VG40R module. This voltage is given to bias the
relay driver transistor. The relay gets activated by just pressing
push-to-on micro switch on the transmitter unit. The relay remains
energised as long as the switch remains pressed. When the switch
is released, the relay gets deactivated. Any electrical/electronic
load can be connected via N/O contacts of the relay.
To activate a relay for a preset period (refer Fig. 3), the switch
on the transmitter unit is pressed momentarily. The transistor
gets base bias from VG40R module. As a result the transistor
conducts and applies a trigger pulse to IC 555, which is wired as
a monostable multivibrator. The relay remains activated till the
preset time is over. Time delay can be varied from a few seconds
to a few minutes by adjusting timing components.
To switch on and switch off a load (refer Fig. 4), a 555 IC and a
decade counter 4017 IC are used. Here the 4017 IC is wired as a
flip-flop for toggle action. This is achieved by connecting Q2
output to reset terminal while Q1 output is unused. Q0 output is
used for energising the relay. The relay is activated and
deactivated by pressing the transmitter switch alternately. So, to
activate the load, just press the transmitter switch once,
momentarily. The relay will remain activated. To switch off the
relay, press the transmitter switch again. This process can be
repeated. Time delay of monostable multivibrator is set for about
one second.
Note: Short length of shielded wire should be used between VG40R
receiver module output and the rest of the circuit. The
transmitter with 9V battery must be housed inside a nonmetallic
(say, plastic) cabinet for maximum range of operation.
|
