128x128 LED Array

This time using "jumbo-tron" type display panels. More specifically, it will use eight of the 64x32 P5 panels which have a 5mm spacing (200/meter).

The original purpose of this project was to build a networked controller to drive this type of array.

Experimenting with a couple of 64x32 P5 Modules

Checking out a potenial diffuser

Since I originally created this page for a 128x128 array, my focus has changed a bit. I am now more interested in smaller pitch panels to allow for better viewing from a much closer distance.

Testing out a two 64x64 P2.5 modules as a single 128x64 array with 128 gray levels.

I used a frosted sheet of mylar as a light diffuser, then place a gray sheet of clear acrylic over the panels which makes it easier to photograph.

To simplify some of the initial experimenting I created a USB interface based on an FT232H from FTDI. The USB interface allows for coding and debugging code directly on the PC with Visual Studio. Note the board at the bottom of the photos.

Functioning analog clock (64x64)
Functioning analog clock (64x64 P2.5 Modules)

I am not too happy with the P2.5 modules. They still do not look so great up close. You need to be at least ten feet away. The next modules to try will be the P2 modules which have a 2mm spacing. They also manufacture P1.667 modules but they are not very common yet and have a higher per pixel price. The P2.5 modules look better in these photos since they appear smaller than actual size.

Functioning analog clock (128x128 P2 Modules)
Functioning analog clock (128x128 P2 Modules)

I have now acquired two P2 modules which are 128x64 pixels each to make a 128x128 panel. The 2mm pitch is a big improvement over 2.5mm when viewing up close. Now it looks very nice from five feet away or so. The panel is 256mm x 256mm which is a nice size for a wall clock.

The pixels at the very top and very bottom of the clock look different because the 4mil frosted mylar sheet I used as a diffuser was not tall enough to cover the entire display. Over that is a 1/8" light gray acrylic sheet to increase the contrast.

What I like about LED panels is the lack of backlight glow. Where the pixels are off it is completely dark.

USB to HUB75 Interface via FT232H
HUB75 Interface

This interface uses the FT232H in synchronous FIFO mode and clocks the LED modules at 30 Mhz.