Fig. A: Radar gun internals including waveguide antenna.
Fig. B: Vertical mount attachment using a sprinkler head.
Fig. C: Waveguide with coiled wire mounts.
Fig. D: Waveguide cable wiring to PCB.
wires to the signal contacts on the antenna’s round it into a U shape. Drill corresponding holes in the
printed circuit board. Also solder the uninsulated display housing and attach the handle using hex
drain wire, which connects to the shielding, to the bolts, nuts, and washers. One of the nice things
board’s ground contact in the middle (Figure D). about the handle is that it also functions as a stand,
Route the opposite end of the cable through the allowing hands-free viewing when the display unit
waveguide housing and PVC nipple, and then care- is on a tabletop or other flat surface.
fully push the waveguide assembly into the housing I needed to make a large hole in the lid of the display
(Figure E). To attach the housing to a camera tripod, housing to fit the LCD display panel. Since I didn’t
remove the tripod’s head assembly and support have any large-diameter bits, I used a ¼" bit to
tube from the base, then route the antenna cabling make a series of small perforations in the plastic.
through the hole, and slide in the PVC nipple and Punch out the section with diagonal cutters, and
waveguide housing. file the edges smooth. Then install the LCD panel
The other end of the cable would attach to the to the lid by running a couple of 1"×¾" sheet metal
display, but I wanted to make it easily detachable for screws through its 2 original mounting holes.
transport. So I obtained a 5-pin DIN male connector To replace the functionality of the original
plug and matching jack. Solder the 3 conductors momentary trigger switch, I chose a double-pole,
that were connected at the other end to 3 contacts double-throw rocker switch. This has the advantage
on the DIN plug. of allowing for automatic, hands-free speed measurements. To install the switch, drill a ¾" hole into the
display housing lid, centered below the display, and
secure the switch in place with its retaining nut.
To reinforce the display and switch, you might also
add some glue.
On the top of the display housing, install the
female DIN connector receptacle, for plugging in
the cable. Drill a ¾" hole into the top of the display
3. Build the display housing.
To house the radar detector’s display and controls,
originally on the back of the toy gun, I used a
6"× 3"× 2" project case. First I made a carrying
handle out of a bar of 0.1" thick steel (aluminum
would have been easier to work with).
Drill ¼" holes in each end of the steel and bend
150 Make: Volume 10