Communicating with an LED matrix

Most of the LED matrix posts we run delve into the hardware design. This time around [J Bremnant] used prefab modules and focused on writing code to address the display. The hardware combines two 24×16 LED boards from Sure Electronics with a Teensy 2.0 to drive the display and provide a USB connection. The firmware comes in just under 8k, leaving graphic manipulation up to a PC.

[J Bremnant's] Python script offers a lot of flexibility when working with the display. There are three modes selectable through a terminal interface. One just tests the display and then drops into Conway’s Game of Life. The second mode lets you send commands via serial interface so it can be used as a message ticker. The final feature is frame addressing that allows graphics to be dropped into the display. See each of these featured in the video after the break.

Comments

  1. acidice332 says:

    Pretty neat

  2. BiOzZ says:

    you think these are bright enough for a low light LED projector?

  3. Erik Johnson says:

    @BiOzZ,
    No, these modules are usually in the 100s of mCD light output

  4. NatureTM says:

    I have a few of these Sure displays, and they’re great for the price. I made a stock ticker + weather report + user-defined message display with a web interface.
    I googled a bit and found that signage like this can be pretty expensive. I was going to go around to some local business and see if I could sell some and make some easy money. As Erik mentioned, however, they’re not extremely bright, and you probably wouldn’t even be able to read it through a store window on a sunny day. Great for indoor use, though.

  5. Frollard says:

    I wanted to pick some of these up – looks awesome. 200fps at full random graphical updates is awesome in that you could easily do 25fps @ 8 levels of brightness faked software pwm.

  6. NatureTM says:

    @Frollard
    They actually have 16 levels of hardware-implemented pwm which can be controlled with a serial command.

  7. jbremnant says:

    @NatureTM/Frollard
    Right, these boards have brightness control via pwm generated from ht1632 driver chips. Since it’s done from that chip, I probably won’t lose fps. It’s just a matter of sending the board right serial command, which is already implemented in the C code (I just haven’t used it yet).

  8. Frollard says:

    That’s awesome news…now I MUST get some!

  9. Tom says:

    Just be aware that the PWM on these sure-electronic boards controls the brightness of the ENTIRE board and NOT the individual LEDs.

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