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freetronics DMD talking to computer through arduino serial

Posted: Thu Apr 10, 2014 12:21 am
by kcrus
I am working on a project that involves a freetronics DMD connected to arduino.
we need to send data from computer via serial port to arduino and then display this on the DMD. your help and input will be very much appreciated as I did search on the web but didn't find a similar requirement/experiment.
Thank you and all the best
KC

Re: freetronics DMD talking to computer through arduino seri

Posted: Thu Apr 10, 2014 3:38 am
by stryker
Hi,

What sort of data will you display - how long is the longest string?

Geoff

Re: freetronics DMD talking to computer through arduino seri

Posted: Mon Apr 14, 2014 12:21 pm
by kcrus
thank you for attempting to reply and sorry about my delay in responding to you as I just noticed you had replied! I will keep a more careful eye in the future.

we will be generating text messages that are as short as 5 to ten words like:
Hi there is no visitors to your store.

and then the message will repeat for maybe a few times... then the next message ..

thank you

Re: freetronics DMD talking to computer through arduino seri

Posted: Mon Apr 14, 2014 2:22 pm
by stryker
Hi,

That's entirely possible, and quite simple as well. Just be mindful that with the smallest standard font you'll only display 5-6 characters on screen at a time, and with the larger bold font just 4. If you're going to display it as a scrolling marquee you might consider more than one DMD wide, granted the length of the messages you intend to display.

Cheers ! Geoff

Re: freetronics DMD talking to computer through arduino seri

Posted: Mon Apr 14, 2014 5:32 pm
by kcrus
could you give me some ideas as to how to do it? any code snippets that I may be able to use please. is there any code some where to transfer what is being typed on the keyboard for example to the DMD through arduino?

if I am able to send even a word through serial port to arduino, I should be okay the rest of the way.
Thanks much in advance

Re: freetronics DMD talking to computer through arduino seri

Posted: Mon Apr 14, 2014 7:00 pm
by kcrus
if anyone has any comments or even pointing me in a direction please.. we are tight for time. thanks

Re: freetronics DMD talking to computer through arduino seri

Posted: Tue Apr 15, 2014 12:32 am
by stryker
Will you construct the message on the PC, send it down the line and just display it on the DMD, or is there some logic required at the Arduino end?

At a high level, you'll be wanting to use Arduino's Serial.read() repeatedly to get the message character by character from the USB port.

Then you'll want to construct a character array out of what you receive keeping track of how many characters there are.

With that character array and length information you'll use the DMD drawMarquee() function, in a loop so it's displayed a couple of times.

Cheers ! Geoff