Neopixel Ring + Electron

Hey All,

I’m super new to hardware in general, so I’m hoping someone can assist with how to hook up a neopixel ring (16 neopixels) to an Electron. I’ve been looking at tutorials and other projects like this tutorial about photon + neopixel and this Alexa project, and I’m confused about two things:

  1. In the tutorial about photon + neopixel, they say that I have to use a logic level converter (shown above) - is there a way to get around this requirement? Like, can I power the neopixel ring separately? If so, how can I do that? I have the particle maker kit, which has a 4-battery holder thing that I think I can use, but unsure if there are details i’m missing.

2… In the Alexa project, the photon seems to be hooked up to the neopixel directly, without this logic level converter (shown above). Does this mean that the Photon puts out 5V, but the Electron only does 3.3V? Can I just follow this wiring diagram using the equivalent pins in the Electron without any changes?

Would really appreciate any light you can shed about logic level converters and hooking up a neopixel ring to Electron. Thanks!

When the Electron is solely powered via the LiPo the voltage on Vin will be V-LiPo (3.7V~4.2V) minus the forward drop of the protective Schottky diode (0.2V), but the NeoPixels want a 5V supply voltage (red wire in your schema) - on the other hand the digital control level (blue wire) of 3.3V is fine in most cases.
So when powering the Electron off a 2A 5V USB supply you may well get away without a level shifter, but with LiPo only a level shifter won’t help you either. In that case you’d probably need a boost converter to boost the Vin-output voltage to 5V.

I have a Burley double kids bike stroller and I put a 3 meter strip of NeoPixel’s around it and I’m powering it directly from a 3.2v LiFePo4 10Ah cell along with a Adafruit 34u2 Feather processor and I can say the Neopixel strip works perfectly fine when supplied 3.2v.

It doesn’t look Dim at all, it’s very bright and people talk about it everywhere we take it.

So powering the LED’s off 3.3v shouldn’t be a problem from my testing although 5v input is recommended.

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Awesome, thanks! Does this mean that it’s safe to follow the Photon diagram above and use the same pin connections for my Electron? I want to avoid damaging anything haha

Nope, I don’t think the frizzing above is safe.
It shows a direct connection between Vin and 3v3 which is definetly a bad idea!

Especially not considering this statement
https://docs.particle.io/datasheets/electron-datasheet/#3v3-pin

Feeding 3.3V into 3v3 is not allowed, even more so anything higher than that.

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Thank you @ScruffR and @RWB! I actually did end up removing the 3v3 -> VIN connection. This is what I ended up doing, and it’s working, hooray!

Hope this helps other people as well. This setup only works if you have power connected via USB as well.

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@chardane, with that many neopixesl on the ring, powering the neopixel directly from the 3V3 regulator on the Electron is not a good idea. @RWB said:[quote=“RWB, post:3, topic:33486”]
I’m powering it directly from a 3.2v LiFePo4 10Ah
[/quote]

That’s fine since all power is coming from the battery directly, not the Electron regulator. :wink:

The updated schema by @chardane shows the ring powered via Vin which should be safe :wink:
But the schema shown by @RWB is not (even after the edit :sunglasses:).

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Your right :blush:

I delete my post. Didn’t think so few neo pixels could pull 960mA when they are all showing white at full power. That’s what you get for Assuming stuff.

Adafruit uses 20mA for their average power consumption per neopixel and that would have put it the safe zone unless she was running them all White at full brightness then that would have put it over the top.

Yeah, I’m taking care to always set the brightness at half or less, but at some point i’ll need to figure out a way to do this better. For now, this setup is good for the prototyping I’m doing :smiley: Thanks everyone!

I’ve captured all my learnings about connecting the Neopixel to the Electron in a blog post, in case anyone who’s unfamiliar with all this (like I was – still am) would find it useful. :smiley:

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