My results were a little different. Pulling the +5V on the 20 module array didn't stop it - it just continued to run dimmer than before with the same aberrations. So I kept the wires connected from the Uno to the 20th module and just disconnected it from all the others, causing them to black out (including module 16 with the problem). I then reconnected the array and they stayed dark; pressed reset on the Arduino and the 20 module array was working perfectly without any corruptions showing.It ran for about 20minutes just now without anything unwanted displaying. I think we have a winner. Thanks again Mel! I'll make sure when this sign goes standalone to include that power cycle on startup.Incidentally, why use the transistor with the IRF9540 since it would appear logic level will be enough to switch that MOSFET on its own?ThanksGeoff
Some breaking news. Tayda Electronics (http://www.taydaelectronics.com) are starting a kit section in additon to their component store and will be carrying instructions for Parola on their kits website http://www.taydakits.com/instructions/parola-for-arduino.
I am guessing here that you are referring to the Parola modules and not Mel's clock project :-)
The video shows connections from a prototyping shield to connect the led matrices and the controls used to demonstrate the functionality of the software, but any of the usual connection methods will suffice.
Hmm, re-reading that seems like a buy a lot of stuff on eBay.