The goal of this ATmega16-based project is to test the feasibility of producing a high resolution LED full-color display for a fraction of the cost. It is anticipated that a system like this will be capable of producing full-motion video; however the scope of the first phase of this project will be focused on developing the hardware and proving that this system is capable of producing images, by updating the display rapidly enough. The end result of the entire design effort will be to produce a product can be sold for very reasonable prices; making it affordable for many to be able to use. It is envisioned that this product will be seen in sporting arenas, theaters, nightclubs, shopping malls, and a variety of other places.
“The project applying the persistence of vision (POV) or flicker fusion threshold principles of the human vision system. By mechanically rotating a group of LED’s at a high speed, the individual LED’s become virtually invisible. Then by blinking (flickering) the LED’s at the precisely the correct times and intervals, the LED’s can produce a visible image,” said Toby Baumgartner, the project designer.
This prototype system uses only 32 RGB LED’s. These LED’s are physically attached a modified 52-inch ceiling fan as the physical spinning platform for the prototype system. The LED Display panel is setup and controlled by several MAX6974 by Maxim Integrated Circuits. The MAX6974 is an LED driver-IC capable of controlling 24 or 48 PWM (Pulse Width Modulation) outputs. It is being controlled in multiplexed mode; this will allow each device to control 48 LED’s (16 individual RGB LED’s).
A custom LabVIEW application was also written to setup and communicate with the LED display hardware. It also is able to import a BMP graphic file and convert it to a stream of polar pixel data. The polar picture data can then be downloaded into the hardware device.
RGB LED Visible Image
Project Firmware, Schematic and Documentation