sensitivity. If the unit is normally dark (in the mail box), set
the rotary switch to the zero position. It will alarm when
the detector senses light. If you want to detect when a
room light goes out or the sun goes down, set the rotary
switch to position 1 and it will alarm.
Solder IC2, noting pin 1. Solder the IC1 socket,
switch, R1, R2, and R3. Add IC1. Solder the speaker.
Clip off the plug to the battery eliminator, thread
through the strain relief hole, and solder the positive line
to the + and the negative lead to the -. Refer to Figure 6.
Put two 6-32 3/8” screws in the mounting holes from
the front of the box. Add two 3/8” spacers. Put the LEDs
with the long lead to the square pads and leave them
loose. Attach the screws to the board. Mount the antenna
as described above. Push the LEDs into their holes. Now,
solder the LED leads to the board. This will give the
correct distance for mounting the LEDs.
Let’s See If It Works
Add three AAA batteries to the transmitter and plug in
the receiver. The receiver LED may be red or green.
1. Put the transmitter in a dark box.
2. Push the reset button on the receiver. The LED
should be green and the alarm should be silent.
3. Take the transmitter out of the box and into the
light. The receiver should beep and the LED should
turn red. The beeper should stay on for about five
seconds. Press the reset button to change the LED
to green. Once the transmitter is placed in the dark,
it will reset.
If you are using the trespass or the proximity detector,
you may want to use the enunciator mode. Hold down
the reset button until the enunciator LED lights. To reset to
the alarm mode, hold down the reset button until the
enunciator LED goes off.
The unit can be built with several applications on the
board that can be changed with the rotary switch.
However, the light, proximity, and trespass use the same
circuit so only one can be used at a time.
Tilt and Switches
The tilt function was designed using an OncQue
RBS070500T tilt sensor. It can be mounted horizontally or
vertically using the pads labeled “tilt.” Check the
specification sheet of the tilt switch for how different
sensors perform. Mount the tilt on the bottom of the
board as shown in Figure 7.
32 October 2013
■ FIGURE 7.
■ FIGURE 6.