Wednesday, July 8, 2009

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.

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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 & *


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Monday, July 6, 2009

4 and counting

We're up to 4 8x8 2 color matrixes. Hopefully move to 5 tomorrow. Then it's time to really start focusing on the power supply.

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Sunday, July 5, 2009

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.

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Wednesday, July 1, 2009

Cutting the cord

Well one of them. We're now offcially wireless. I got 2 xbees talking to each other and was able to move my 2 matrixes across the room. This article here helped a lot with setting up the xbees. Next step will be power. Preferably we'd run on solar power (I can get one matrix running & xbee if I plug straight into the solar panel) still working on wiring up the battery and running off of that.

Of note I didn't have to change my arduino code at all, just plugged one xbee straight into the iobridge, GND->GND, 5V->5V, Rx->Tx & Tx ->Rx. The other xbee went to the arduino, 3.3v ->3v, GND->GND, Rx ->Tx & Tx ->Rx. Simple as that. Photos shortly, gotta charge my camera.

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