Signal Processing - January 2017 - 35

Usually, an ultrasonic signal and an IR signal are sent back
simultaneously from the leading car. The second car can
determine the distance by detecting the time-lag between the
receiving ultrasonic and IR signals.

Beacon-based racing
Unlike the other competition categories, there is no visible
racetrack in this competition. Several beacons are distributed
on the competition field and can be turned on by a referee
system in a random sequence. Model cars should move to
approach the lighting beacons. As long as a car moves inside
the detection region of a beacon, the referee system will turn
on the light of the next beacon. The arrangement of the beacon group field is illustrated in Figure 10.
The challenges of this competition include detecting targets
that may be located relatively farther away from the race car,
avoiding collision onto the beacon during the navigation, and
planning a motion path for the race car.
Many participating teams have used a camera to search for
the beacon. To differentiate from the surrounding light sources, the beacon flashes at about 10 Hz. This flash pattern is used
to locate the beacon in the middle of ambient light. Participants
have shown that target detection based on the frame difference
image is a robust approach to locate the beacon in most types
of environments.

Figure 9. Students preparing two chasing cars on the racetrack.

Beacon

Field Border
Judgement
Computer

B2
dc

Forward-looking innovation category

B1
B5

To foster creative thinking, the IMCC also has an open-ended
category inviting teams to contribute innovative ideas and
designs. Different themes are set up for each year. The most
recent competition's theme, for instance, was innovative
designs on energy saving and a future smart city. Teams are
required to submit a detailed technical report as well as a video
of their work. The top teams are invited to the final race each
August to showcase their work. Figure 11 shows a winning
entry of a recent competition, where the student team designed
and prototyped a parking facility in a futuristic community.

Bus Interface
Module

Competition Field

Figure 10. The beacon group competition field.

Signal processing techniques used in the competition
There are many different technologies used in a model car to
compete in the respective category [6], and signal processing
is one of the key components. Students receive hands-on
training and strengthen their understanding of signal processing through the competition.

Signal sensing and sampling
As the model car is controlled by the MCU, almost all signals coming from the sensors would be sampled and converted into digital. Some of these signals are already digitized by
the sensor module themselves so that they can be passed
directly from the sensor to the data transfer port of the MCU.
Some other sensing signals are obtained in an analog form,
for example, the photoelectric sensor signal and induction
coils signals. These signals need to be sampled after conditioning circuits by an analog-to-digital converter (ADC)
module on the MCU.

Figure 11. An exhibit of the creative design category of the IMCC.

As students learned from fundamental signal processing
courses, the sampling frequency need to be properly determined according to the property of the signal. For example,
the signal that comes from the induction coils in the two-wheel
competition has an alternate voltage with a fixed frequency of
20 kHz. It is a narrow-band signal, and thus with proper processing, it could be sampled at a frequency that is far lower

IEEE Signal Processing Magazine

January 2017

Table of Contents for the Digital Edition of Signal Processing - January 2017