Floating LED Display

Projects in Computer Engineering II

Phil Sherry
Josh Zimmerman

Utilizing a spinning mirrored surface attached to a DC Motor, a message appears on seven 14-segment LED displays.  This acts like a heads-up display (HUD).  The user controls the message(s) being displayed via a graphical interface on a PC.  The PC is connected to a Motorola HC12 microcontroller with the IEEE1284 interface (parallel port).  The seven character display is controlled with the HC12 and two Altera EPM7128SLC84 FPGAs.  The user can customize the output by following the provided recipe commands (print, loop, date, and time commands are included).

Figure 1 shows the user interface.  Messages are entered on the PC with a GUI generated with the Python programming language.  The message is then displayed by the LED display.  Figure 2 shows the LED display internal diagram.  A mirror is attached to a DC motor, which reflects the message displayed on the 14-segment LEDs.  An infrared LED is mounted across from a sensor.  As the rotating apparatus spins, the LED is obstructed from the sensor, causing the sensor to generate periodic TTL signal.  This signal is used to synchronize the flashing of the display as the mirror passes by.  Figure 3 shows the electrical connectivity of the system.  The HC12 is connected to the PC via port A (for commands) and port T (for handshaking).  The motor position sensor is fed into bit 7 of port T.  Ports B and P are used to control the FPGA that actually drives the seven 14-segment displays containing the message.  The A/D port is unused.

Figure 1:  User Interface

Figure 2:  Internal Configuration

Figure 3:  Electrical Connectivity

Design Review

Status Reports
Report I
Report II
Report III
Report IV
Report V
Report VI
Report VII

Report VIII