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Need something smaller than the metro mini for a glow ring.
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Please be positive and constructive with your questions and comments.

Need something smaller than the metro mini for a glow ring.

by live4film on Wed Jan 15, 2020 1:20 pm

I am trying to fit neopixels inside a special ring with a microcontroller that doesn't take up too much space. I am currently using a Metro Mini. Aside from the fact that dealing with the drivers for this particular board is difficult, it's simply too large. I need a very tiny controller. Maybe even one that can be powered by some coin cell batteries. I'm also wondering if even using a neopixel and controller are the best for this project. The light and controller and battery all need to fit inside this little container attached to the rings (almost like some brass knuckles). There is some text cutouts that need to have the light shine through.

I'm open to suggestions. I like neopixels because I can program them, but I am fine with a more simple LED that just as one color. Also for the battery, I think it has to be coin cell, or maybe some sort of tiny flat lithium battery that can lay down inside.

Thanks!
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live4film
 
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Re: Need something smaller than the metro mini for a glow ri

by adafruit_support_carter on Wed Jan 15, 2020 1:36 pm

Some ideas for smaller boards:
https://www.adafruit.com/product/3500
https://www.adafruit.com/product/3800

But also consider a Feather, since it has built in battery charging:
https://www.adafruit.com/product/3857

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Re: Need something smaller than the metro mini for a glow ri

by live4film on Wed Jan 15, 2020 1:47 pm

Oh that's cool that the battery is built in! I'll try it out. Thank you!

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Re: Need something smaller than the metro mini for a glow ri

by michaelmeissner on Fri Feb 07, 2020 12:52 am

A feather is not going to work since it is wider, taller, and longer than your Metro mini.

Lets see:

Code: Select all | TOGGLE FULL SIZE
Processor:                W x L x H (mm)               W x L x H (inch)       Lipo
=========                 ==============               ================       ====

Metro Mini:               18mm   x 44mm   x 4.0mm     0.7" x 1.7" x 0.2"      No
Feather Basic M0:         23mm   x 51mm   x 8.0mm     0.9" x 2.0" x 0.28"     Yes -- charger from USB
Trinket M0:               15.3mm x 27mm   x 2.8mm     0.6" x 1.1" x 0.1"      No
Gemma M0:                 28.0mm x 28.0mm x 6.4mm     1.1" x 1.1" x 0.25"     Yes -- no charge
Itsy Bitsy M0 express:    17.8mm x 36.0mm x 4.3mm     0.7" x 1.4" x 0.2"      No


Now, neither the Trinket M0 nor the Itsy Bitsy have a JST port for connecting a lipo battery, but it has two pads underneath that you can solder in the JST connector. However, the JST connector adds to the height of the board. I would suggest instead use a JST female wire to hook up the JST port, but move it off the board, so it doesn't add to the height.

Except for the larger Feather board, the other three options (Trinket M0, Gemma M0, and Itsy Bitsy M0) do not charge the lipo battery. So you must make some provisions for charging the battery.

Do not get the original Trinket or Gemma. These use the ATtiny 85 microprocessor, which is extremely limited, and is not compatible with some modern systems these days. Get the M0 version.

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Re: Need something smaller than the metro mini for a glow ri

by michaelmeissner on Fri Feb 07, 2020 1:55 am

Another thing if you need small space is to build your own AVR 328p of AVR ATtiny85 board. You would need to use a programmer to download the code.

AVR 328p (equivalent to Arduino Uno):

AVR ATtiny 85 (very small, very limited, but still can do a few neopixels):

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Re: Need something smaller than the metro mini for a glow ri

by adafruit_support_carter on Fri Feb 07, 2020 3:09 pm

Maybe as another source to go for some options:
https://circuitpython.org/downloads

There are some people out there putting together some super tiny boards. Like the Serpente or the uChip M0.

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Re: Need something smaller than the metro mini for a glow ri

by jdelcamp11 on Thu Feb 13, 2020 8:44 am

If there isn't an onboard charger on the board you pick, this is a very small one.
https://www.adafruit.com/product/2124

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