Feasibility of scrolling indicator text

Hi,
I have 7 of the 8x8 led matrix modules, and wondered if it was feasible to run scrolling text, or maybe just arrows, through an Arduino and MAX7219 to scroll one way when the right indicator is on, and the other way when the left indicator is on.
I have found a number of posts on here relating to scrolling text, but none of them illustrate this possibility. Or maybe I've just not found one yet.
I am also too old to start learning a new programming language, although I'm OK with VBA, and can understand a lot of the logic on most of the posted sketches. I wouldn't mind paying for a sketch that could achieve my goal.
Any takers?

Have a look at this How to scroll text using multiple MAX7219 LED Dot Matrix.

Thanks for the response Whandall, but I still don’t see how to get it to scroll the other way when powering it from a different switch (indicator)

olorin65:
Thanks for the response Whandall, but I still don’t see how to get it to scroll the other way when powering it from a different switch (indicator)

Read your switch whatever it is.

Then use If -Else to scroll left or right.

The library supports shifting in all directions

    void shiftLeft(bool rotate = false, bool fill_zero = true);
    void shiftRight(bool rotate = false, bool fill_zero = true);
    void shiftUp(bool rotate = false);
    void shiftDown(bool rotate = false);

olorin65:
Hi,
I have 7 of the 8x8 led matrix modules, and wondered if it was feasible to run scrolling text, or maybe just arrows, through an Arduino and MAX7219 to scroll one way when the right indicator is on, and the other way when the left indicator is on.
I have found a number of posts on here relating to scrolling text, but none of them illustrate this possibility. Or maybe I've just not found one yet.

At least in the German forum I posted some sample code for China-made red 8x8 LED matrix modules with MAX7219 for scrolling ASCII-TEXT two years ago or something like that.

But although the code was intended to scroll text from right to the left and users reported that it worked fine, at least one other user wrote that with his module the text is scrolling from top to bottom of his 8x8 matrix.

I never managed to get left to right scrolling working - although it's perfectly do-able but the MAX7219 library I used didn't (seem to) support it.

Additionally I first thought the 'rotate' was to actually rotate the glyph but it just meant to put the sprite-column back onto the end of the buffer so the whole message kept repeating.

I haven't had to time to either revisit the library or create my own code (the bit I did for my video tutorial took long enough as it was).

So if anyone can confirm that left to right scrolling works with a particular MAX7219 library then I, for one, would be very interested :slight_smile:

Oh, that top to bottom scrolling happens on some LED matrices that have been mounted side-by-side (instead of end to end) - the physical construction looks fantastic (exactly what we need but the logic of sending rows of data instead of columns of data would take some doing).

Ralph_S_Bacon:
I never managed to get left to right scrolling working - although it's perfectly do-able but the MAX7219 library So if anyone can confirm that left to right scrolling works with a particular MAX7219 library then I, for one, would be very interested :slight_smile:

Software scrolling direction is depending on the software.

Scrolling text on relatively slow updating devices looks best if the scrolling direction is opposite to the reading direction.

So if your reading direction is rom right-to-left (i.e. Hebrew language, then left to right scrolling might be useful for Hebrew text.

But in most countries/languages the reading direction is from left to right, so the best readable scrolling is right-to-left scrolling for text messages.

Maybe in your case (no long text messages( and scrolling just an direction icon, it may be better to make the scrolling direction on the icon displayed;:
displaying right arrow: scroll it from left to right
displaying left arrow: scroll it from right to left

But in case of displaying long text, it's better to always scroll text opposite to the reading direction. IMO.

Thanks to all that have taken the time to reply to my query.
Being an old guy that is very new to Arduino and sketches, I still do not understand how the arduino would know if I had turned on the left indicator, or the right indicator. Does the arduino uno have the option for two different power inputs and thus running the script depending on which power input was live?

Yes, you have that figured out right, but your terminology is, shall we say, slightly off course.

The Arduino has General Purpose Input Output [GPIO] pins that can be used to determine which are set to a 'high' voltage (max 5v) or a low voltage (0v) and hence take the correct logical route in its code.

To be honest, scrolling text using the generally available library is easy to do when scrolling from right to left. As previously mentioned (and no-one has come back with an alternative) I did not get scrolling from left to right to work.

If you're a beginner you need to get some basics under your belt so you understand what the Arduino is all about - it's a fascinating subject but can be totally overwhelming to the newcomer.

I have an ever-growing list of beginner-type videos that describe various aspects of the Arduino (see the URL in the signature of this post) and may help (no, I'll say it: will undoubtedly help) you see what the Arduino can do, in small steps. So have a look and, ideally, subscribe so you get notification of new ones (usually weekly or thereabouts).

Once you've grasped some basic fundamentals other ideas will naturally follow, never mind you being a self-proclaimed 'old guy', you can learn just the same as everyone else here does!

Ralph_S_Bacon:
Yes, you have that figured out right, but your terminology is, shall we say, slightly off course.

The Arduino has General Purpose Input Output [GPIO] pins that can be used to determine which are set to a 'high' voltage (max 5v) or a low voltage (0v) and hence take the correct logical route in its code.

Thanks again for your time in answering.
What I was trying to say in my own way, was that I can't get my head around how the Uno would know which indicator on my bike was powering the board. I even thought about having two boards. One for the right indicator, and another for the left. But then I wondered how I could wire the matrices up with the two boards. Bet hey ho.
I will indeed head over to your site and subscribe.
I obviously need to learn more

To get you started..

The arduino and displays will be powered from a power source that is on whenever the bike is running. Depending on which arduino you may need to step down the voltage from 12V to 5V using some kind of regulator.

The turn signals will be connected to GPIO pins on the arduino- you need to use resistors or diodes to limit the voltage to 5V at the arduino or else you will destroy it.

Your program then uses digitalRead() to detect when a turn signal is active and perform an action. I suggest you start with the digitalRead example sketch in the arduino GUI to get a feel for how this works.