Science Technology Make a Cheap & Easy Solar USB Charger With an Altoids Tin By Jaymi Heimbuch Writer California Polytechnic State University, San Luis Obispo Jaymi Heimbuch is a writer and photographer specializing in wildlife conservation. She is the author of The Ethiopian Wolf: Hope at the Edge of Extinction. our editorial process Twitter Twitter Jaymi Heimbuch Updated October 11, 2018 Share Twitter Pinterest Email Science Space Natural Science Technology Agriculture Energy Photos by Joshua Zimmerman The craftster behind the very popular $3 solar-powered emergency radio is back with a new awesome project: a cheap solar battery charger with a USB plug. Zimmerman wrote, saying that he saw a lot of small solar powered chargers being talked about over Earth Day, but there was a big problem: "They're all quite nice, but also quite expensive. I don't think I've seen any for less than $60, and I've not seen one that really suits my style." So, he came up with his own, using one of our favorite reusable items -- the ever wonderful Altoids tin. In looking for the cheapest way to accomplish the task, Zimmerman found that he could build a USB solar charger for under $30 (or $10 if be buys parts in bulk, though it's not likely you'll be buying bulk solar cells and DC-to-USB converter circuits). Zimmerman states, "The central brain of our project is a DC to USB converter circuit. This takes our AA power and changes it into the 5Vs we need for charging USB." It can be done with a Minty Boost kit, a premade circuit off of ebay, or grabbing one from a cheap USB charger. With all the right spare parts and an hour or two of craftiness, you can have a cheap solar charger that fits into your pocket for emergency charging. Joshua ZImmerman has the full instructions over on Instructables and you can check out his Brown Dog Gadgets website where he has parts, or even a complete kit that you can use for creating this project yourself.