The other day I got 3 8X8 Led Matrix modules in the mail from China.
I was bordering on wigging out that I wasn't going to be able to figure out how to use them, but alas I did.
First thing I learned,
If you are going to order something that you think is the same as something on a major USA supplier's site, don't order it from China unless they have the data sheet for the assembled unit published and you can compare them.
Next I learned
Don't place orders when you are exhausted, you make stupid choices.
Even if you do make a stupid mistake, usually you can figure out some way to make it better.
So I thought I was ordering the same modules as Adafruit has with an I2C driver, But this one uses some other method of communication to the MAX7219 chip. I guess it is serial, but I dont know enough about communications methods to actually know what I am talking about. So I got them and discovered my matrix had more wires connecting it to the Arduino than the Adafruit one, so I began searching the net, looking for something that had the same connections, Which are: CS, CLK, DIN, VCC and GND.
I tried 3 or 4 different tutorials online and none of them were giving me anything on the matrix or all they did was turn the whole thing on solid. Finally I found one that worked.
I have figured out how to scroll text over the 3 units that I bought and have hooked up to an Uno and cascaded them.
Now there are still things I need to figure out, but I am sure in time I will figure them out. I have not figured out to get anything to display other than scrolling text, but I haven't fooled with it much yet.
Next steps in this grand project:
Figure out how to get text to scroll or to just display stationary and switch between methods
Figure out how to get the temperature from a sensor displayed on the cascaded matrix
Figure out how to get 2 Arduinos to communicate with each other (I haven't even looked into this yet, so some guidance of where to look would be helpful)
Figure out how to use more than one type of display on one Arduino and have them display different things that change at different times
Figure out how to make a program that will allow me to change the text that is displayed on the scrolling matrix without having to plug into computer and upload a new sketch (nope haven't even looked into this either)
There are a lot of things I still need to learn, But it is coming along slowly but surely. at the rate I am going I should have a working prototype of my project in about a year. I hope it is not that long, but I know my limitations. At least I get to make a lot of cool little things to play with and learn from along the way, it is like every time I get mail i have a new thing to learn.
I can't wait till my Ethernet shield gets here, I am hoping I can learn to use that for 2 things that I need for this project.
1 - Communication with the internet to get airport METARS data to display on LCD
2 - I don't know if this is possible, but to use the SD card slot to record temperature data from my sensors.
ok, now I am going to go try to use my RTC module to get the LED matrix to show the time. This should be interesting.