Led Ring ideas?
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I am having the same issue with a ping sensor. I've run it on a 3.3v Pro Mini with a boost to 5V for the sensor. Next I tried a Sparkfun Redboard because it has 5V for the ping and 3.3V for the radio. Both configurations worked well when connected to the PC. Both do not work with power from a USB charger. I tried several different wall chargers. One would not let it run at all. The others seemed to let it run once through the loop function. I thought something on the data pins of the USB might be an issue. Tried commenting out all my serial.print()s and turned off DEBUG. Didn't help. What is different between the PC USB and wall charger USB that could cause this?
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So you find very close to 5V at the pixel chip level while running?
You are probably not missing something basic, but instead have a tricky marginal situation that's genuinely hard to debug.
If it was low power from the 5v charger (just not enough milliamps available), you should still be able to control, say, one red pixel on at a time, even if "all pixels white" overloaded the power supply.
The level shifting is one thing to check as others have indicated. Some 5v chargers run a little high (charge the battery faster?) which might make 3.3v logic driving data input of 5V pixel more marginal. You could insert a logic level shifter, or use a loose WS281x pixel running at the 3.3v between your Arduino and the first real pixel (adjust your code to send out one dummy black pixel before everything else).
Alternately, you could insert a resistor in the data line. in case it has to do with transmission line effects. Say, 47 ohms - give or take.
Also some of the cheap phone chargers have a very noisy power output. You might try using multiple bypass capacitors of differing values (eg: smaller ceramic for high frequency, higher value electrolytic for low, etc).
This is one of those times that a 'scope could be handy - maybe even one of the very cheap ones, used carefully. I'd really like to see a trace of that power line.
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I am having the same issue with a ping sensor. I've run it on a 3.3v Pro Mini with a boost to 5V for the sensor. Next I tried a Sparkfun Redboard because it has 5V for the ping and 3.3V for the radio. Both configurations worked well when connected to the PC. Both do not work with power from a USB charger. I tried several different wall chargers. One would not let it run at all. The others seemed to let it run once through the loop function. I thought something on the data pins of the USB might be an issue. Tried commenting out all my serial.print()s and turned off DEBUG. Didn't help. What is different between the PC USB and wall charger USB that could cause this?
It turns out I WAS missing something basic. The wall outlet I was plugged into was experiencing intermittent problems (loose connection) So the reason it worked on the PC and not on the charger was because the PC has batteries. Duh . ....
I did improve my power set up considerably and learned a lot from the suggestions in this thread in the process of troubleshooting. -
Well, first of all thank you all for the help.
I've been doing some tests this days ... also tried with the same configuration a relay node and had exactly the same issue.
Well ... as soon as I changed the arduino to a 5V one, everything worked.
Project completed. :)
Thank you all!!!
