I write up a lot of guides on Instructables for various solar gadgets. Most of the Solar USB/ iPhone/ Arduino chargers. If anyone is interested in such things I sell them off my website, which I then use to make more projects or fund activities in my science classroom. I have several versions of my kits available as well as all the parts to make those kits, and even premade chargers for those who don't feel the urge to make one on their own. Solar USB Charger and Kit A basic USB charger that uses rechargeable 2 AA batteries, a DC to DC boosting circuit, and a 4V solar cell. Take the batteries out to charge, or leave it in the sun for a few days. Then charge up your gadget when need be. Works with most USB devices including Apple products (iPods, iPhones, iPads) as well as Arduinos. Fits nicely into an Altoids tin. Solar iPhone Charger and Kit More or less the same as the USB charger, but instead of having a generic USB port it has a dedicated iPhone/ iPod/ iPad cable. Which means it only works with Apple stuff. Features 2 rechargeable AA batteries, boosting circuit, Apple Connecting Cable, and 4V solar cell. Heavy Duty Solar USB Charger and Kit While the 4V solar cell in the other kits/ chargers fits nicely inside an Altoids in it is also quite wimpy. I took the basic design of the Solar USB Charger and replaced the 4V solar cell with either a powerful 6V 230mA or a 5.5v 320mA solar cell. In order to make things easier the solar cells plug into a 2.5mm jack on the side of the tin. Meaning you can leave the solar cell at home. The solar cells are also powerful enough to charge up a lot of gadgets directly from the sun if you have good weather. Works with most USB gadgets, Arduinos, and Apple products. Lithium Heavy Duty Solar USB Charger and Kit Due to the fact that big gadgets (like iPads) have insanely big internal batteries I had to modify my design a bit. The AAs in the other chargers were not powerful enough (unless you used 4 or 6 of them) to reliably charge up bigger items. I modified the design of the Heavy Duty Kit to replace the AAs with a Lithium battery and Charge Controller. With several battery options available, including a massive 6,600mAh one, these chargers have no problem handling the larger power needs. On a recent plane flight a charger with a 2,000mAh Lithium battery charged up my iPhone over 80% (on airplane mode while listening to music). Imagine what a 4400mAh or 6600mAh battery could do. The charger/ kit can fit inside an Altoids in with the smaller batteries. It features a powerful 5.5V 320mA solar cell and a 2.5mm jack and plug system so you can easily remove the panel. A nice addition is the Lithium Charge Controller which has status LEDs showing when the battery is charging and when it's full. It works with most USB gadgets, including Arduinos and Apple gear. I've used these kits with kids at my middle school, and have sold many kits to summer camps and scout groups. They take between 20 and 45 minutes to make, and only require basic soldering skills to put together. They all fit inside Altoids tin for cuteness factor, but can easily be put into something else. Modifications are endless. So there you have it. More Altoids solar thingys than you can shake a stick at.