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Trinket and NEOPixel power consumption
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

Re: Trinket and NEOPixel power consumption

by pkclsoft on Mon May 17, 2021 2:25 am

well, after 4 and a half days, it was a sad little trinket. The battery had run out. Still not great. I'm holding off the final packaging of it now whilst I run these lifetime tests. I'm charging it again now and will see if it's consistent.

After this next run, I'll eliminate one of the pixels and see what sort of difference that makes.

It's a slow process. 4.5 days is much better than 2, but it's not very much considering what the thing does.

Does the trinket draw more power if the run loop is checking every time for the sensor input? At the moment, the loop always checks the sensor, even if it's in the mandatory sleep mode (after having recently triggered). If I tell the trinket to sleep for a minute instead, will that use less power?

Additionally, if I sleep for a second every time through the main loop when there's been no trigger, will that reduce power consumption? It would reduce the responsiveness but I don't think it would be noticeable.

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Re: Trinket and NEOPixel power consumption

by dastels on Mon May 17, 2021 10:58 am

Fewer NeoPixels and/or running them at a lower brightness will reduce the consumption. I forget now... do you just need white? Maybe swap for white LEDs. That would mean 20mA each instead of 60 to get bright white. Or a RGBW NeoPixel and use the white component when white is needed.

RGB is a very expensive way to get white.

Dave

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Re: Trinket and NEOPixel power consumption

by pkclsoft on Mon May 17, 2021 6:43 pm

OK. Darn. I just have so many spare WS2812B LEDs on hand it seemed to make sense to use a few of those.

I only use white as a colour because the device is being used as to provide light when someone walks into a dark nook in the house. I could go for a warm white, but I'm guessing the colour doesn't affect the power consumption.

If I change to white LEDs, can I still control the brightness so that I can fade-in/out? I'll look around for a circuit to do that if that's the way I have to go. I'll also look at dimming the light to see what sort of difference that makes.

Thanks for your continued assistance.

Peter

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Re: Trinket and NEOPixel power consumption

by adafruit_support_bill on Mon May 17, 2021 7:35 pm

Don't forget the roughly 1mA per pixel idle current for the WS2812. That will be a constant drain even when the lights are out. Using standard analog white LEDs controlled by a PWM pin via a MOSFET would be more efficient.

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Please be positive and constructive with your questions and comments.