rotating R4 until LED1 just goes out and then back off R4
until LED1 comes back on. Remove the jumper from pins
1 and 2, and move it to pins 2 and 3 instead for normal
If all has gone according to plan, you should now be
able to walk your hallway without ever having to turn on
another light again!
Now that my hallway is automated, I plan on building
additional modules to control other rooms in the house.
The laundry room was built with the same problem — you
have to walk across the room in the dark before you can
turn on the light. In the bedroom — where I’d want the
light to come on when I enter but turn off when I’m ready
to go to sleep — I’ll add a SPST momentary pushbutton
switch between pin 2 of IC2 and ground. Then, when I’m
ready to turn in for the night, I just push the button and …
lights out! In the master bathroom, there’s a double-door
that stays closed (due to el gato). There, I will replace the
IR detector with a magnetic reed switch pair, increase the
delay time constant for IC2, and do away with IC1 and its
related components. As you can see, the base circuit is
Don’t think that lights are all you can control with this!
The relay I used (scrounged from an old CRT TV chassis)
can switch loads up to 10 amps at 250 VAC or 24 VDC.
Depending on the exact relay you select, your mileage
may vary. Hopefully you found this interesting, or at least
■ FIGURE 9. How NOT to mount the receiver!
Live and learn.
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