Electronic-Geek.com

Every other week, MAKE's awesome interns tell about the projects they're building in the Make: Labs, the trouble they've gotten into, and what they'll make next.

By Tyler Moskowite, engineering intern

I recently received my first smart phone, an iPhone 3GS, from my brother who just got back from Iraq. It has turned into my PDA, map, social networker, and a boatload of other stuff I didn't even know it was capable of doing. Let's just say simply, I love this device. Which has prompted me to want it to be on every moment of everyday, and let's be honest, the iPhone 3GS eats through battery life at a decent rate. Being a somewhat outdoors-active person, and because I enjoy the planet that I live on, I decided to build a solar charger for my iPhone 3GS.

When I started researching best way to build one of these, the simplest way was obviously to start off with a MintyBoost USB Charger Kit v2.0. Make sure to pick up the v2.0 and not v1.2, as the iPhone 3GS will not work with a v1.2 kit. This is due to the voltage on the D+ and D- pins that the iPhone 3GS uses to connect to USB. (Malaysian student Chen Tzy Wen has posted a good guide explaining how the voltage on each pin works, and the comments have good information in them as well.) Using the two 100k? resistors worked fine to charge the iPhone.

This design allows for a power source to be attached to the MintyBoost to charge your iPhone 3GS via a USB cable. Included in the kit is a 2xAA battery holder, but I wanted a more renewable and longer lasting energy source.

Comments are closed.