Projects II Design Review: Floating LED Display Phil Sherry Josh Zimmerman

Project Outline Programmable 7 character LED display Programmable 7 character LED display Uses a single 14-segment display Uses a single 14-segment display  Characters appear to float in space due to rotating display Output fully customizable Output fully customizable  Can output 0-9, A-Z, some symbols

User Interface Display is controlled by HC12 and programmed via PC Display is controlled by HC12 and programmed via PC Parallel Port HC12 Port A

System Interface

Internal System Diagram LED display is flashed at specific times after detection by sensor LED display is flashed at specific times after detection by sensor Rotation of 30Hz gives illusion of stationary displays Rotation of 30Hz gives illusion of stationary displays

Initial Concerns LED dims appreciably at low duty cycles LED dims appreciably at low duty cycles Slip rings and synchronous AC motors hard to find Slip rings and synchronous AC motors hard to find  Price quotes not readily available Use an alternate design? Use an alternate design?

Alternate Internal Diagram Reflected image of seven stationary LED displays produces same result Reflected image of seven stationary LED displays produces same result Need front faced mirror to prevent ghosting effects from glass refraction Need front faced mirror to prevent ghosting effects from glass refraction

Alternate Interface

Comparison

Software Interface Recipes editable from GUI and loadable from text files Recipes editable from GUI and loadable from text files PC interfaces with HC12 with parallel port and handshaking PC interfaces with HC12 with parallel port and handshaking

LED Display Protocol Bits 1 and 0 of port T used for handshaking Bits 1 and 0 of port T used for handshaking Ill-formed requests are ignored Ill-formed requests are ignored

Recipe Command Syntax Current message stays displayed until another message is printed or loss of power Current message stays displayed until another message is printed or loss of power Ill-formed commands are ignored Ill-formed commands are ignored

Example Recipe

Budget

Timeline and Milestones

Q&A