LED below 10mA and 1.4V

[mrgoos]

Looking at the power your panel supplies I really wonder what size they are. Most panels can get you around 100 W / m^2 (in direct sunlight... any cloud makes numbers drop like a rock), so you get roughly 10 mW per square centimeter. That probably is enough to drive a power LED, albeit at a very low power, so it won't be visible from a distance unless it's completely dark. Still, if I look at the thread here about XM-L at low power you should get several lumens from it.

I'm using solar panel for indoors... This is why i have these properties.
And it's a very efficient one.

Yes, i have 325mW and i can add some together but i see that it won't help a lot.
I could add 10 or so...

What if the LED will blink like 0.5 second off and 0.5 second on?

Thanks.

 

[Freeze_XJ]

Blinking reduces power requirements by 50%, but does require you to wire a circuit to it. Those tend to be quite efficient for higher powers, but at these levels (assuming you have to build one in a shed from COTS caps and ICs) the power to keep them active is going to eclipse any gains you might possibly get. Your problem is that you really can't use anything more than the very basic electronics (a few resistors and a cap, perhaps a coil) or you'll loose too much power there. Also know that most common ICs tend to run on >3V, too.

(note that this assumes microwatts, if you really have the milliwatts your margin increases by quite a lot. In that case a strobe could be an option, ie 5-10% of the time 'on', otherwise 'off', so you get 10-20 times the brightness you'd otherwise have, as well as attract attention )

 

[mrgoos]

500 millivolts and 650 microamps means you have 325 microwatts

BTW that's not true.
If i had 0.5v and 650uA i will have power of 0.325mW and not 325mW.
So i do have a current of 650uA and voltage of 0.4v so the power for 1 unit that i have is 260uW.
I understand that it's not much and even if i add 10 units i will get 2.6mW which apparently won't be enough for LED right?
2.6mW could give me 1mA and 2.6V - Is there a LED that will work under these conditions?
What is the minimum that i should get in order to meet my requirements?

Thanks.

 

[idleprocess]

BTW that's not true.
If i had 0.5v and 650uA i will have power of 0.325mW and not 325mW.

0.5V * 0.00065A = 0.000325W ... 325 microwatts (10^-6 watts) if you stick to common engineering notation (keeping your multiplier >1) or 0.325 milliwatts (10^-3 watts) if you really want to stick to milli- notation - which is a bit confusing and misleading, thus the preference to use multipliers >1.

So i do have a current of 650uA and voltage of 0.4v so the power for 1 unit that i have is 260uW.
I understand that it's not much and even if i add 10 units i will get 2.6mW which apparently won't be enough for LED right?
2.6mW could give me 1mA and 2.6V - Is there a LED that will work under these conditions?
What is the minimum that i should get in order to meet my requirements?

Thanks.

You will have to await a response from someone that can design these circuits; I'm good with basic Ohm's law stuff, LED basics, and little else.

You'll need to produce close to 3.6V and at least a few milliamps to run blue/green LED's. With some sort of power storage, DC/DC conversion, and intermittent use you could do that with 2.6mW. If your usage is truly intermittent and your storage capacity can easily meet what your solar panels generate, you could likely run them at full brightness for several seconds an hour.

 

[CKOD]

Blinking reduces power requirements by 50%, but does require you to wire a circuit to it. Those tend to be quite efficient for higher powers, but at these levels (assuming you have to build one in a shed from COTS caps and ICs) the power to keep them active is going to eclipse any gains you might possibly get. Your problem is that you really can't use anything more than the very basic electronics (a few resistors and a cap, perhaps a coil) or you'll loose too much power there. Also know that most common ICs tend to run on >3V, too.

(note that this assumes microwatts, if you really have the milliwatts your margin increases by quite a lot. In that case a strobe could be an option, ie 5-10% of the time 'on', otherwise 'off', so you get 10-20 times the brightness you'd otherwise have, as well as attract attention )

When youre at ultra low power requirements like this, you dont use normal ICs so much as discreets in cleverly designed circuits. I'd look at BEAM robotics stuff for inspiration.