LED Matrix Fairplay hack

Details

Using an old Fairplay Scoreboard LED matrix to display scrolling messages (one of which was also for the kiddos birthday, scrolling "HAPPY BIRTHDAY")

A PIC 16F870 was used for the controller. The factory controller was ditched as I was unsure how to use/program it. I still used the factory board for the 5V power supply (seems kind of silly to have the large board just as a 5V power source, but it worked)

To reverse engineer the LED driver board, I looked into the datasheets of the populated board and eventually came up with a shift register and clock design. (being it has been a few years since I actually reversed engineered it, I may get some of the facts mixed up, so bare with me).

From what I remember there is clock timing that will have to be seen by the board or it will error out and a red LED will light up (more or less a visual indicator to let the user know that there is a clock signal being sent to the board). But once that stays within its specs, the green LED will light up letting me know that I had the timing right.

There are 3 clock lines, two for the two separate boards column shift register clock and one for the row select clock.

There is then a single data line to send the LED light sequence for the selected row. This is sent to a shift register and then displayed.

Sticking to what I am comfortable with I used asm and timer interrupts.

I am throwing around the idea of making a serial interface to quickly change the scrolling text. Right now I have to reprogram the code to change what text I want to scroll. Currently it is set to "2 TICKETS = 1 PLAY".

Components

1 × Fairplay LED matrix with driver board

1 × 100 uF Cap (across the 5V to gnd)

1 × 4 MHz crystal (and two associated caps)

1 × 16f870

1 × 100W 7.5V power supply

Project Logs

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Code Release
willbaden • 11/23/2014 at 15:45 • 0 comments

Matrix_Display code can be viewed here:
https://github.com/baden0001/Matrix_Display
If you have questions, leave a comment or shoot a message over.
Omaha Mini Maker Faire
willbaden • 09/15/2014 at 00:13 • 1 comment

The display survived the whole day of the maker faire. A picture of it can be seen on the Claw Machines project logs page. It continuously scrolled "OMAHA MINI MAKER FAIRE 2014".
As for the other stickers that Kritina Panos gave me, here is where the other .IO sticker is now attached.
Speed Control
willbaden • 09/03/2014 at 02:24 • 0 comments

For an input, I used a 10Mohm pot to control the speed of the scrolling. This fed into AN0 of the 16F870 through a 10kohm resistor. The pot is installed on the lower side of the panel for easy access.
A jack was added to aide reprogramming of the PIC. The is located @ the top of the perf board in the picture below:
New Enclosure
willbaden • 09/02/2014 at 00:17 • 0 comments

The matrix display is being prepared for the Omaha mini maker faire. It needed to be enclosed to keep prying hands away from the 120V power. The enclosure was a scoreboard controller box that was saved from scrapping. This was the perfect size to fit the matrix display in.
As seen in the picture below, the left hand side is the cover to the right hand side base.
The cover had louvers punched into it that will eventually be removed for the matrix display to reside.
The controller box utilized a noise suppressor which will be reused for the scoreboard controller. The transformer and power plug-in will not be used. Instead a 7.5v power supply and standard plug in cable will be installed.
The ends had 7 - 15 pin connectors which were removed. These will be kept for future projects.
Below is the layout of the boards and power supply. Starting at the top of the picture is the controller board. This currently is configurable only through reprogramming the code to allow for different messages to be seen. I plan on updating this as soon as I can find some more time. The second board from the top is the original controller board. Really the only thing that is used on the board is the 5v power supply and header for connecting to the matrix display. The next component down is the 7.5 V power supply which feeds all the led's and the original controller board. At the bottom is the noise suppressor.
After I knew the components would fit, I then modified the face to allow for the matrix to be mounted. The plasma cutter ended up warping the ends of the face, but once installed on the base, it flattened out. Along the left of the face, the original louvers can be seen. These were hammered down and then some electrical tape was laid along the edge to hide the damage. This made it more eye appealing.
The boards were then mounted to the base and wired in.
The matrix was installed to the face and here is the assembled product: