Hi,
for low power project I would like to use energy harvesting from a small photovoltaic panel. Solar powered calculators or some toys use those and I guess they produce just the right voltage to power a MCU. Since out local shop does not have such small panels I tried to look at eBay but I did not find anything useful. Only panels like this one - voltage is only 0.5V but current is too large - 100mA they say. Also the panel is too large. Do you know where to get the small panels used in calculators? Maybe I only don't use the right phrase so I cannot find then? Or are solar cats the only source of such panels?
Thanks
One good source would be discarded solar calculators.
Solar garden lights.
Well I could buy some solar garden lights and/or calculators/toys only to get the panels from them - but it seems quite wasteful. I expect such panels would be super cheap - but where to get them? (Let alone they are much smaller and more suitable for noncritical device which measures something and sends data wirelessly when enough energy is acccumulated.)
Are there no "thrift stores", second hand shops, flea markets or garage sales in your country?
Calculator parts and the like are custom made by the millions for manufacturers and are generally not available for individual purchase.
What voltage/current are we looking at (solar and project).
An 0.5volt/100mA solar cell can become 3.3volt/10mA once you run it through a boost/charge controller.
That 100mA might be 20mA on a cloudy day, and only for a few hours.
How are you storing it. Supercap?
Leo..
I just remembered that Solarbotics used to sell small solar panels, and indeed they still do.
37x33 mm panel, 6.7V/20 mA
Used calculator panels can be had for free, though, if you are motivated to look for them.