Computing stuff tied to the physical world

Running LED ticker #2

In Software on Nov 2, 2011 at 00:01

After the hardware to feed yesterday’s scrolling LED display, comes the software:

Screen Shot 2011 10 25 at 18 31 38

The code has also been added to GitHub as tickerLed.ino sketch.

Fairly basic stuff. I decided to simply pass incoming messages as is, but to do the checksum calculation and start/end marker wrapping locally in the sketch. The main trick is to use a large circular 1500-character FIFO buffer, so that we don’t bump into overrun issues. The other thing this sketch does is throttling, to give the unit time to collect a message and process it.

Here’s what the display shows after power-up, now that the JeeNode is feeding it directly:

DSC 2705

(that’s the last part of the “Hello from JeeLabs” startup message built into the sketch)

So now, sending a 50-byte packet to node 17 group 4 over wireless with this text:

    <L1><PA><FE><MA><WC><FE>Yet another beautiful day!

… will update line 1 on page A and make the text appear. The unit rotates all the messages, and can do all sorts of funky stuff with transitions, pages, and time schedules – that’s what all the brackets and codes are about.

Time to put the end caps on and close the unit!

  1. Why do I now have a mental image of the display mounted in JC’s “play room” with a message saying:

    “Dinner is ready!”



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