PCB Christmas tree Ornaments

[hobbyProgrammer]

Hi,

I would like to create a christmas tree ornament consists of a few LED's (no more than 20, maybe even 10/15).
It needs to be light weight, but I would also like it if it would last long.
After all I don't want to change batteries 3 times a day.
But I also don't want it to be ridiculously expensive as I'm going to hang multiple (5/10 pieces) in the tree.

Do you guys have any tips on how to build this circuit or what batteries I should use?

Sorry for asking such a beginners question, but this seems like a fun project to start with.

 

[ads-ee]

It needs to be light weight, but I would also like it if it would last long.
After all I don't want to change batteries 3 times a day.

Conflicting statements IMO.

Batteries are not lightweight, if they are they have little to no capacity and therefore don't last long, which means you are changing batteries all the time.

If you use 1.2V red leds and put 20 of them in series with a resistor you need 24V so a lot of batteries to increase a 1.5V alkaline to 24V. If you use a 3V lithium then you use less but lithium's are even heavier than a typical alkaline battery. If you put the 20 LEDs in parallel with a resistor then your battery will see maybe 200mA of current (assuming the LEDs are 10mA ones). With a AA battery you might get a usable 10 hrs at such a drain rate probably significantly less as an alkaline voltage will degrade to the point where it will be less than the forward voltage of the LED. But a AA is kind of heavy for an ornament.

I'd suggest using only 1 or 2 leds per or 1 led and a bunch of fiber optic filiments to the outside of the ornament to generate light on multiple sides instead of individual leds. I'm sure such an arrangement will work a lot better and require less battery changes, due to only having 1 battery supplying 10mA, but it will be much more complicated to build and will be way more expensive.