DIGILENT DESIGN CONTEST • DIGILENT DESIGN CONTEST • DIGILENT DESIGN CONTEST • DIGILENT DESIGN CONTEST
FIGURE 4. Manual driving demonstration.
software, the smart shopping cart achieves manual
cart driving, automatic following, an RFID electronic
key, a voice shopping guide, and self-checkout.
Following are brief descriptions about these features.
Manual Cart Driving
A game joystick is installed on the handle of cart
so users can control movement style in all directions,
including forward, backward, left, and right. The cart
will automatically stop when sensors detect obstacles
on any side. The cart’s running speed can be adjusted
to ensure safety of operation. When customers feel
tired during shopping, they can simply stand on the
supermarket cart and switch it to driving mode.
way for the RS-232 IP core to be supported by the Xilinx
Spartan 3E; we only need to call the IP core and change
some serial port parameters to achieve any related
functions, so operation is very simple. The supermarket
scanner module uses a PS/2 keyboard interface on the
FPGA. This is because the scanner output code signal is the
same output signal as the number keys on the keyboard.
The other module’s interfaces to the system use the Pmod
interfaces on the FPGA. Pmod interfaces are reserved for
additional sets of general-purpose input/output interfaces;
these are flexible and can link directly to the FPGA chip pins.
Through the development of the hardware and
The smart shopping cart provides a new
shopping experience: just release your hands and
focus your attention on the products you need to buy; your
supermarket cart will follow behind you. In case the smart
cart is faced with different environments, it has been set up
with infrared sensors and a camera for its following mode.
The infrared following mode is simple to implement. The
tracking effect is good and isn’t easily impacted by
interference in the environment. One issue is that the
infrared mode cannot distinguish between different people;
the cart will follow any moving objects that appears in front
of the cart. This error may occur unexpectedly, and is
difficult to autocorrect.
One way to avoid this problem is to join the camera
mode with the infrared sensor mode. When using the
image tracking algorithm and the wireless camera module,
the smart cart will follow the initial target image during the
following process. The algorithm
distinguishes the target image to
the rest of the environment, based
on relevant physical characteristics.
By using algorithms, the smart cart
can automatically find the target
image in the environment, achieve a
track positioning, and adjust itself to
the correct location. With a
combination of the two tracking
modes, the cart can achieve
automatic tracking and automatic
Voice Shopping Guide
To help make the supermarket
FIGURE 5. The automatic following
54 SERVO 02.2012