I’m not certain where to post this, so mods are free to relocate it or yeah… smack me over the head with a cod and point me to wherever…
I find that I have a small problem…
very small in fact.
My hobbies include painting miniatures, and sticking LEDs in them. And now I want to make the LEDs flash, brighten and dim in patterns, not just shine with the same brightness all the time.
So what is the issue?
I need to fit a MCU and a battery under a typical miniature base.
(A 25mm base has about 22mm ID, and about 2.5mm inside height)
The smallest I’ve found is the TinyLily, which is about 14mm in diameter.
That doesn’t leave me room for a proper battery such as a CR1220, so if I want to use that I’ll have to use a pair of smaller Silver Oxide batteries, or go for a larger base.
The Silver Oxide batteries have issues, and a larger base looks unnatural on single minis.
So I would like to make an Arduino compatible that’s half-moon shaped, so that it fits around the battery, and have connectors on the outside edge.
The connectors would be half-circle cutouts as if you after drilling and plating holes, cut away the outer edge, bisecting the holes.
(This should save at least 1mm diameter.
For programming I was thinking an adapter somewhat like the one used for the TinyLily, but with pogo pins.
I learned programming a long time ago, even did some assembly on some 8bit platforms(6502, Z80, 8051) and some high-level languages, Pascal, ADA, C, even C++ (C++ is not something I want to mess with again… ) but the relative simplicity of the Arduino seems best suited for this.
What is the smallest MCU currently supported by the Arduino toolchain?
(either length or widt of package + pins. )
If there’s nothing smaller than the AtMega328p, how much work is it to re-tool for a smaller chip?
(The ATtiny814 SOIC150 is slightly smaller along one side. Yes, I’m desperate for space. )
I can solder 0805 SMT without too much issue, and have even done 0603 once, so assembling a board or three should be no issue.
I don’t have reflow tools, so BGA or other packages with contacts underneath is not an option for me.
(If anyone else wants to grab the idea and make a production run, feel free, but I doubt the market is large enough for it to be profitable)