8 MAX72XX is the limit

I reached the limit on how many MAX7219's can be chained together. That's 8. Good article here, so I'll have to use another 3 outputs on the arduino for my 5th matrix. Photos soon.

External Power

So I did some reading and some internet searching, and think I have at least part of the power issue figured out. I purchased a 7805 +5VDC Voltage Regulator, wired up my 1/2 size breadboard as my external power supply and added an led to that board and to 3 others down the line as a visual to see if power is being routed properly. Now with just the ground from the Arduino going into the circuit I can get everything operating properly. So the next test will be to get a Voltage Regulator with a higher current rating and a heat sink to get up to the current I need to drive all of the leds. 2 internet posts that helped a bunch. *ITP Physical Computing & *http://pixelriot.com/pmatp/node/285

Also http://www.tkk.fi/Misc/Electronics/circuits/psu_5v.html

Wiring things properly helps

So my knowledge of how breadboards work or lack there-of may of been stopping me from adding more matrixes to my test system. I now have 3 working, although one only can show green as I'm waiting for more Max7219s. They should be here tomorrow, so hopefully I can get 5 (the amount I've purchased so far) matrixes up and running. I still need to figure out the solar system for the 3 signs on hill and how to add extra power after the arduino runs of of forward current to drive the matrixes. Hopefully I can find that threshold.

If anyone out there in internet land can help me with these calculations I would be greatly appreciatative. Here are the datasheets for all of the parts. AT Mega 328(Arduino), XBee, 8x8 Led, Max 7219.