The SMDs from the Arduino nano

Hi, I want to build a biosphere project with a house in the middle as a gift for someone. What I really want to do is to light the interior of the mini house with a little little smd for a duration of a minimum 1 year 24/7 My arduino nano have some, even if is not white I think they consume as little current as they are.

So what are the specifications of those SMDs? Are they 0603 led? |500x271

Are they 0603 led?

Yes.

Apart from that, that package does not orders of magnitude difference in brightness per mA. So use whatever you want. The common 3.2V of white LEDs are close to the voltage of a LiPo, so you probaly won't be much more efficient with anything else than current limiting resistor. So mA in the LED equal mA drawn from the battery. To run the LED at 20mA for a year, you would thus need 20mA*24*365, so a 175Ah battery, or about 60 smartphone batteries or a car battery with an efficient buck converter. You probably won't need 20mA, but even with 1mA, you are still at quite a big battery pack.

When you say biosphere, there should be light, shouldn't it? Perhaps you can use solar cells to charge during day? that would also be more in line of the biosphere idea.

ElCaron: Apart from that, that package does not orders of magnitude difference in brightness per mA. So use whatever you want. The common 3.2V of white LEDs are close to the voltage of a LiPo, so you probaly won't be much more efficient with anything else than current limiting resistor. So mA in the LED equal mA drawn from the battery. To run the LED at 20mA for a year, you would thus need 20mA*24*365, so a 175Ah battery, or about 60 smartphone batteries or a car battery with an efficient buck converter. You probably won't need 20mA, but even with 1mA, you are still at quite a big battery pack.

When you say biosphere, there should be light, shouldn't it? Perhaps you can use solar cells to charge during day? that would also be more in line of the biosphere idea.

yep,i thought that led, being too small it consume very very low amount of current, not 20mA. And about the solar panel, i tought the same but then i also need a charger and maybe a step up convertor and all this stuff... using a cr2 battery with ~900mA at 3V i need to have a have a drain of 104.1uA (0.1041mA) to keep it alive for 1 year, and if this little sh*t consume 20mA then i don't think there is anything that could

prologikus: yep,i thought that led, being too small it consume very very low amount of current, not 20mA.

0603 is a small package, but the LED chip itself is pretty much the same as in any other indicator LED package. It's worth noting that 20 mA is the maximum current for the device. They emit light at lower current levels, though the light output is also reduced. It's common for LEDs used as indicators to be run well below their maximum rated current.

And about the solar panel, i tought the same but then i also need a charger and maybe a step up convertor and all this stuff...

Consider hacking one of those solar LED lawn lights/ornaments, which would have the complete system. Of course it's also possible to build the same from components.

prologikus: yep,i thought that led, being too small it consume very very low amount of current, not 20mA.

That is what I explained in the very beginning: The package doesn't work magic. It does not increase the efficiency of LEDs by orders of magnitude, and it doesn't generate light from nothing. So it doesn't really matter in first order if you connect a big 5mm through-hole led, or a tiny 0201 led. The max rating will be lower with the latter, but in the end, the light at 1mA will be the same.

I agree with MrMark. Salvage some garden gadget. If not because it is really the only way to get this going on small scale, then because a battery powered biosphere doesn't make much sense.