edge is used to insert the power
connector on the AC adapter.
Once fitted, remove the
piezo and set aside.
■ FIGURE 15
• STEP 12
First, we need to build the
base. This will allow the detector
to stand free. Cut a piece of
1-1/2” PVC pipe to about 2” as
shown in Figure 17a. Take a 1-
1/2” PVC cap and drill a 1/4” hole in the center as shown
in Figure 17b. Next, drill a 1/4” hole in the center of a 1-
1/2’ PVC cross as shown in Figure 17c.
To assemble the base, run a 2-1/2” #6 machine screw
down through the inside of the PVC cap, then the section
of pipe, and finally through the hole in the PVC cross as
shown in Figure 18. Place a nut on the end of the screw
on the inside of the cross and tighten. As an option, you
can drill a 1/2” hole on the other end of the cross and
insert the machine screw through the bottom of the PVC
cross. Then, go up through the small pipe section and into
the cap. The goal here is to have the cap attached to the
cross so that you can attach a 24” piece of tubing.
■ FIGURE 14
■ FIGURE 16a ■ FIGURE 16b
• STEP 13
Peel off four leads of ribbon cable about 3’ long as
shown in Figure 19a. Strip each lead on both ends. Attach
one end to the EZ4 sensor as shown in Figure 19b and
Figure 19c. You will use the GND, + 5, RX, and AN. The
RX lead is used to disable the sensor when not in use.
• STEP 14
Take both of the 24” pieces of pipe and drill a 1/2”
hole in each. The hole should be located at 18” from one
end and 6” from the other as shown in Figure 20.
I built my stand out of 1-1/2” PVC pipe. It’s inexpensive
and can be painted. For this part of the project, you
will need the following:
• Two pieces of 24” 1-1/2” pipe
• One piece of 2” 1-1/2” pipe
• Two 1-1/2” PVC caps
• One 1-1/2” PVC cross
• One 1-1/2” coupling
• One 2-1/2” machine screw and nut
• STEP 15
Using some double stick foam tape, attach the EZ4
sensor module to the pipe, and run the cable through the
hole as shown in Figure 21. As an option, you can use
some small wood screws to attach the module to the
pipe. Just mark and drill some small pilot holes into the
• STEP 16
Insert one of the pipes into the PVC cap on the base.
■ FIGURE 17a
■ FIGURE 17b
■ FIGURE 17c
December 2008 43