PowerBoost 500 Shield - Second shield to die this week.

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IanLukeFinley
 
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PowerBoost 500 Shield - Second shield to die this week.

Post by IanLukeFinley »

Folks, I'm at my wits end. Last week I posted (viewtopic.php?f=19&t=192422) that the PowerBoost Shield I had received had stopped working after only a few seconds, and refused to activate again. I presumed I had just done something wrong, so I ordered another, which arrived today. And the same exact thing.

That is: I carefully solder on headers and switch. I plug in a LiPo 3.7V 2000mAH battery and set it in my adafruit Metro. Initially, it worked fine: flip the switch, lights on both boards turn on, brilliant. I then connect the two LED strips in this project to the 5V and GND out and pin 6. When just one strip is attached it works fine. BUt when I connect the second strip of LEDs, they run for maybe three seconds, and then everything stops.

And again, I cannot get the shield to turn on at all at this point. It is the same result I had with the previous shield. I don't know what I'm doing wrong here. Both LED strips total are about 30 neopixels. The second LED strip is connected by a fair length of wiring (it's at the feet of a costume), but besides that, there doesn't seem to be anything unusual about that connection. Can anyone give me any direction? I now have two dead shields and I'm supposed to have a photo shoot with this costume this week.

As a note, I previously was running this system through a PowerBoost 1000 rechargable, and it ran just fine, but I had to use that board for another project and I can't find a way to get another one anywhere. Any guidance would be grateful received!

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dastels
 
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Re: PowerBoost 500 Shield - Second shield to die this week.

Post by dastels »

It's most likely related to the current draw of LED strips. 30 NeoPixels can draw up to 1.8 amps. In comparison the shield can provide 500mA (half an amp) or so with spikes of 1 amp. The Powerboost 1000C can supply 1A or so comfortably with spikes somewhat higher than that. There are techniques to lower the current demand of the Neopixels. See https://learn.adafruit.com/adafruit-neopixel-uberguide.

Dave

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adafruit_support_bill
 
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Re: PowerBoost 500 Shield - Second shield to die this week.

Post by adafruit_support_bill »

Another approach is to eliminate the need for the boost altogether. Use a 3.3v processor like one of the Feathers and power both pixels and processors directly from the 3.7v LiPo.

Neopixels run just fine on 3.7v and most of the portable/wearable neopixel projects in our Learning System are powered that way. The only catch is, when you power them with 3.7v, you need a 3.7v or lower control signal. But there are a lot of 3.3v processors to choose from.

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IanLukeFinley
 
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Re: PowerBoost 500 Shield - Second shield to die this week.

Post by IanLukeFinley »

Thank you so much for your responses. The NeoPixel document you shared, which I have somehow missed ever seeing, is of enormous help.

It seems like there is a very easy solution based on that, but let me post it here to see if there's something else stupid I'm overlooking:

Wire up three AA battery holders in series. This should supply ~5V. Run these into the VIN and GND inputs on the Metro board. Run the NeoPixels into the 5V and GND output pins and Pin 6 for data.

Is it really just that simple? Can I stop crying now?

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adafruit_support_bill
 
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Re: PowerBoost 500 Shield - Second shield to die this week.

Post by adafruit_support_bill »

Wire up three AA battery holders in series. This should supply ~5V. Run these into the VIN and GND inputs on the Metro board.
3xAA alkaline cells will supply around 4.5v. The Metro needs 7V at VIN for the regulator to properly regulate. But you could feed that via the 5v pin - bypassing the regulator. Still a bit under-spec, but it should be sufficient for the Metro to function.
Run the NeoPixels into the 5V and GND output pins and Pin 6 for data.
Better to connect the power source directly to the pixels - since that is by far your biggest load. Then run power and ground from there back to the Metro.

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IanLukeFinley
 
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Re: PowerBoost 500 Shield - Second shield to die this week.

Post by IanLukeFinley »

Thank you all so much for your help on this. The AA solution helps a great deal, though it's led to other issues, but I'll post about those on the NeoPixel forum. I am so grateful for your help!

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