First time poster here: I'm working on a Daft Punk Helmet replica and have been having some issues powering my LED arrays.
Some background on the hardware: The schematic for the Max7221 hardware shows a 5V in and common ground with the arduino, with 3 inputs from the arduino (data, load, and clock). These are all then daisy-chained for however many Max chips you need, my project has 8 of them. I have created and tested PCBs for the Max circuits, they're all fine to the best of my knowledge.
Picture of Grid+PCB setup: http://i.imgur.com/G9geM22.jpg?1
Successful powering (kind of): I'm able to power the whole daisy chain without errors, but only if I power it through the Arduino board's 5V output while it is plugged in via USB to my computer through its Breakout Board http://store.linksprite.com/breakout-board-for-ft232rl-usb-to-ttl-5v/ . This however doesn't supply the correct amount of current, so the LED intensity is somewhat dim
Errors I've encountered while troubleshooting:
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Powering the Arduino via USB+breakout board and the controllers separately via external 5V power supply http://www.mouser.com/ProductDetail/Triad-Magnetics/WSU050-3000/?qs=sGAEpiMZZMt5w6YCUaBPUXrfhsD5E87BmbkiZEpAU5I%3D (all with common ground): This will power the daisychain for maybe 4 seconds and then the grids in the chain will begin to fail, starting with the last in the chain moving towards the first.
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Powering the Arduino Via external 5V power supply via the "RAW" pin and controllers via the same power supply (all with common ground): sees the same error as 1.
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Repeated 1 and 2 with battery packs (6.5 V and 4.5 V sets of AAs respectively): the 4.5 V was able to last longer than 5 seconds without failing, however still succumbed to the same problem. The 6.5 V never even turned on the grids.
Ideal Scenario: My endgame is to power both the arduino and the controllers by a rechargeable battery pack. This is somewhat problematic if I'm only getting error-less power via usb though. For the moment I just want to power it with my wall power supply and then eventually transition to the battery once I'm finished with other parts of the helmet's design.
Interesting things to note:
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In case 1: when I powered the LED controllers but removed the input from the arduino (i.e. unplugged the arduino and removed common ground), the grids all powered up without error. They were all stuck in the "on" position because they were not receiving any input from the arduino, but this says to me that its an issue with the arduino that's causing the grids to fail, not something with my power supply.
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This is a quote I found on this forum about my redback model from linksprite:
"I talked to linksprite tech support about my problems and they tested the boards that they had in stock. They said that the silk screen has a print error and there is no 5v output on the RedBack, only 3v. However when using the FTDI breakout to power the board it does do 5v output."
As far as I can tell, that says to me that I can only get 5v output via the arduino itself if I power it from usb: however I'm pretty sure I can't get enough current draw through the arduino to keep up with the LED intensity.
I'm heavily considering buying a new arduino (either a mini or micro) since this one is giving me so much trouble. I just wanted to run one last troubleshoot by you guys/gals to see if I missed anything.