Full Color Hi Res POV Display - MS&T Senior Design
This page describes progress on Robert Givens' and my Senior Design Project at Missouri S&T. Our project of choice was a Persistence of Vision (POV) display. However, to make it innovative, we decided to make ours particularly high resolution and most importantly with full color capability. Our current goal is 256 (8bit) colors. This project encompasses the fields of Microcontrollers, FPGAs, Inductive Power, Optics and high speed circuit design. These individual elements are broken down in detail below.
The rotor is made up of multiple PCB's which are held together with hardware and spun to draw the image in the air. The rotor is made up of three PCB's. The front most PCB which we call the "LED Board" contains the LED's and electronics to drive the LED's. The next PCB which is located in the middle is called the "FPGA Board". The "FPGA Board" contains an FPGA which decodes the signal and sends the data to the LED board to be displayed. The last board in the rotor stack is called the "Power Board" this board contains the power circuitry to rectify the AC power from the inductive transfer and it also contains the high speed photo diode circuitry.
The LED Board is just that - It is the board that contains the LED's and the led drivers/shift registers.
- RGB LED's
- Count: 48
- Type: Common Anode
- Model Number: PLCC4RGBCT-CA
- Bought From: http://leading-leds.com/rgb.html
- LED Drivers/Shift Registers
- Count: 9
- Model Number: STP16CPP05TTR
- Bought From: Digikey (Part Number: 497-8735-1-ND)
This is (perhaps obviously) the display Printed Circuit Board for our POV assembly. This board consists of 48 surface mount RGB LEDs mounted at precise spacing. This board was the most difficult due to the precise position, size and number of components. This PCB is a 2-layer (traces and components) standard FR4 PCB with 8mil minimum spacing and trace size. Layout was done in Mentor PADS after aborting the effort with Eagle. Without basic push/shove routing and enforced design rules, it was nearly impossible to make progress without having to go back and delete 15 traces because the 16th was 0.1mm too close to the edge.
- Altera Cyclone II FPGA
- Count: 1
- Model Number: EP2C8T144C8N
- Bought From: Digikey (Part Number: 544-1666-ND)
Optical Transfer Ring
In order to transfer data to the rotor in real time we had to find a method to transfer it wirelessly because the rotor is spinning. We decided to transfer the data optically because of the high data rates that would need to be achieved to allow at least 24 fps of streaming video. The optical transfer assembly uses two circular channels one for the clock and one for the data. The base of the assembly is a PCB which has the rings of high speed IR LEDS mounted to it.
Inductive Power Transfer
Motor and Base
So far two applications have been developed to make this project possible. Read more about them by clicking on the images below: