I'm curious if anyone has experience with getting a simple board like the Adafruit Trinket or DigiSpark or any of the other ATTiny based clone boards running on solar power. E.g. with a solar panel and a lipoly or other rechargeable battery.
There are a combination of things that must be accomplished for that to work "well" (e.g. with the smallest possible battery and panel) which are not trivial.
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The Trinket has to sleep in low power as much as possible. That probably requires cutting off the power indicator LED, and then using some tricky code to actually put the chip into low power modes.
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The Solar Panel has to be controlled so it doesn't discharge the batteries at night, and doesn't over charge the batteries during the day time.
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The battery needs minding as well, depending on the type.
When you add all that up… well… I'm hoping someone else has done it? Or part of it?
Best Answer
Is size a concern? Are you planning on making a custom board?
If you just want to slap a few modules together, this is easy enough.
Along with the Trinket, get the USB/DC/Solar charger from Adafruit - http://www.adafruit.com/product/390
The IC on the board will prevent any over-charging.
Sleep code is easy enough for the 85 - here is a more info: https://learn.sparkfun.com/tutorials/h2ohno/low-power-attiny