Arduino Solar Tracker + Charger

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lawrenceyy
 
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Arduino Solar Tracker + Charger

Post by lawrenceyy »

Hey,

I am trying to build a solar tracker with solar panels that will power the Arduino that is driving the whole contraption. Think of it sort of like a plant- I want an animate machine that does not add to the power bill. The Arduino has no other purpose than to take readings from the light dependent resistors and drive the motors accordingly every 5-10 minutes. I know that my solar panels probably won't be able to collect enough energy to keep the Arduino on constantly (hence the 5-10 minutes of sleep), so I was hoping that there was a solution where I could charge a battery with the solar power and have that same battery power the Arduino when it wakes to track the sun (hopefully the battery will have enough charge by then). Is there a board that can do that? I see that Adafruit has a board that charges a battery, but it does not have the option of powering an Arduino at the same time. Think of your laptop battery- you can charge the battery and use the computer at the same time.

Any thoughts?

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adafruit_support_bill
 
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Re: Arduino Solar Tracker + Charger

Post by adafruit_support_bill »

I see that Adafruit has a board that charges a battery, but it does not have the option of powering an Arduino at the same time.
I don't know which board you are thinking of, but all of our chargers allow powering a load while charging. For solar charging, you will want to use the solar charger. It can supply power for a 3.3v Arduino compatible (e.g. Pro Trinket) directly.
http://www.adafruit.com/product/390
If you want to use a 5v Arduino, you can add Verter between the charger and the Arduino:
https://www.adafruit.com/products/2190

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lawrenceyy
 
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Re: Arduino Solar Tracker + Charger

Post by lawrenceyy »

Thanks for the advice. I am still relatively new to Arduino, so I have some follow up questions for you.

Is the Pro Trinket essentially the same as the Arduino Uno (which I have) except for the fact that it's meant to be attached to a bread board? Currently I am able to drive a small nema 17 stepper directly from the pins of my Uno and was wondering if the Pro Trinket would put out enough power to do the same?

Regarding the solar charger you pointed me to, it says that it needs a 6V solar panel. I am using a much smaller solar panel (2-3V), will the battery still charge?

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adafruit_support_bill
 
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Re: Arduino Solar Tracker + Charger

Post by adafruit_support_bill »

The Pro Trinket has the same Atmega 328P processor as an UNO and the pin output capabilities are the same.

As for the solar panel, you need an absolute minimum of about 5v to charge. The full charge voltage on a 1S LiPo cell is 4.2v and the charger needs a little headroom above that.

With lower voltage cells, you could possibly charge some NiMH cells. These are less fussy about the charge cycle than Lithium cells and you can get away with a simpler circuit. Here are some simple solar circuits from our evil mad scientist friends: http://www.evilmadscientist.com/2008/si ... -circuits/

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