June 2017 11
relay based on what kind of
load it will switch. The relay I
chose can handle a standard
120 VAC 60 Hz circuit with
up to two amps of current. I
operated a remote 60 watt
lamp. Choose your relay
contacts to operate whatever
the remote controlled device
is.
In experimenting with
range, I found it amazingly
long. All I needed was a
couple hundred feet, but
there was a clear path from
transmitter to receiver. If there
are obstacles like trees, fences,
or houses in the way, the
signal could be blocked. The
signal can penetrate walls, but
the walls do greatly attenuate
the signal and shorten the
range. You will need to
experiment with your setup to
see what works. NV
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FIGURE 3. The messy but fully operational breadboarded transmitter and receiver. The
nine volt batteries are not shown. Note the Radiometrix modules. The vertical wires are
the antennas. The relay is the black box on the right of the receiver in the foreground.