how to build a solar harvester?

My team and I are building a device that allows homeowners to monitor their homes' electricity usage. I would like for my device to be energy efficient by implementing some sort of solar harvesting module to the device's mcu. Any suggestions would be greatly appreciated.

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Oct 28, 2009. 9:25 PM

Molten Boron says:

Probably a simple photovoltaic panel should suffice for its energy needs, if they aren't too much. But it'll get complicated if you need power to it 24 hours a day. Essentially, in this case, you'll need a battery to charge using the excess power from the panel during the day, which then powers your MCU at night.

Oct 30, 2009. 6:40 AMdoc0016 (author) says:

Thanks for the idea. I realize that a solar panel will not provide enough power to the MCU that is why we've also thought about coupling a solar array with maybe an RF harvester. Any clues about that? We're in the early stages of our design so we're just throwing suggestions out. Thanks in advance.

Oct 30, 2009. 9:57 AMMolten Boron says:

I'm assuming you're talking about this kind of MCU? How much wattage does it eat?? Normal ones consume power measured in MICROwatts, which you can get from a garden-decor solar light.

And, as an aside, RF harvesters won't be efficient enough for my liking (say, to act as a stand-in for a solar panel) for at least another decade.

Oct 31, 2009. 4:55 AMdoc0016 (author) says:

Yes it is a PIC MCU provided by Mikroe Elecktronica and max consumption:
220 uW and stand by: 50 nA or 11 uW.

Actually we've found a harvesting module which we will use that accepts various energy sources. Therefore we'll be looking to build just the solar panel for now and since the device will be indoors the light source will be mainly incandescent.

I did not realize the present ineffeciency of RF harvesters. Thanks for the insight on this.

Nov 1, 2009. 3:34 PMMolten Boron says:

Now that I think about it...
RF harvesters collect energy in the microwatts...
And they work as long as there is a radio source, like a big radio station near you. See this article.

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