Checkouta specialpodcaston thisproject! Goto www.savagecircuits.com fordetails.
BY CHRIS SAVAGE
When we moved into our new house, we upgraded to a bigger garage than
we had before. My wife now parks in the garage — something she did not do
before. Her main problem is not knowing how far forward to pull the car in to
leave enough room in front of and behind the car. Instead of the traditional
tennis ball hanging from a string, I decided to take a more hobbyist approach
to the problem at the risk of negatively impacting tennis ball sales.
Free of Tennis Balls
The Garage Parking Assistant makes it easy to park in
the garage by signaling you with a traffic-light style display
of when to pull in (GREEN), slow down (YELLOW), and
stop (RED). If you pull in too far, the red LED blinks to let
you know you need to back up a bit.
Although this type of project has been done several
■ FIGURE 1.
Zone range map.
ways, I wanted to take my own approach and simplify
the code and hardware while making it easy to adjust
and personalize for your own use. By default, all
measurements are in inches, although you could easily
use centimeters since that information is available as
well. All you would need to do is replace all instances
of inches in the main loop with cm. If you’re using a
laptop to debug distance, you will need to uncomment
the debug line that displays cm and comment the one
that displays inches. Finally, you will need to change
the constants for each zone since they are specified in
The range of the PING))) sensor we’ll be using is ~0.8
inches up to 3. 3 yards and is split up into four zones
labeled Zone1 through Zone4. Figure 1 shows a map of
the zones. The values in the constants section for each
zone are inches from the sensor/wall.
Zone1 (Striped) is closest to the sensor/wall and
indicates the area you don’t want to occupy. When you
are in this zone, the red LED will flash on/off to indicate
you are too close. In our garage, this area is big since we
want to have plenty of room in front of the car. The
default setting for Zone1 is 36 inches (three feet).
Zone2 (Red) is the area where you want the front of
the car to stop in. This will be between the Zone1 and
Zone2 settings. When you are in this zone, the red LED
will be solid telling you to stop since you are in the
desired zone. You don’t want to make this zone too small
since you will need to stop within it without having to
keep adjusting. You also don’t want to make it too big.
The default setting is 46 inches, giving you a 12 inch
buffer. When you set this, you want to make sure it is
far enough away from the wall as well as have enough
clearrance from the garage door.
Zone3 (Yellow) is the area in which you want to
slow down and be prepared to stop. When you are in
this zone, the yellow LED will be on letting you know