Right, so! Around the time of the tsunami getting all up in Japan’s business I had begun spending more time working on little electronics projects. SEKRET PROJECT was just about complete (still needs a hole for the speaker but other than that, done) and some of the other tinkering was all well and good, but I needed a new direction. I decided to make a solar charger for my phone.
The reasons I decided on this one were threefold:
- Plenty of people had done something similar or identical to what I was trying, so it’s not like there wouldn’t be help available… not that it was difficult.
- I’ve never really played with solar before, and it seemed like an interesting, yet practical way to tinker with it.
- The Tsunami inspired a lot of hacker spaces (eletronics tinkering groups) to try to come up with ideas that could be mass produced simply to help people. In turn this got me thinking about building stuff like that in emergencies.
And so, I got to work. The concept is quite simple. The solar panel (6v, 2w, 330mAh max) would output power into a LiPo, a lithium-ion polymer battery. This would be accomplished with a LiPo charging circult, a small chip readily available online. In turn, the chip would output to a small USB charger device that the tinkering community is very fond of: a MintyBoost (so-called because it’s usually stored in an Altoids tin). By connecting the circuit to the MB instead of its normal twin-AA battery pack, it could provide power to any device I plug into a USB to charge: phones, e-books, GPS devices, some types of cameras, whatever. I decided, on a whim, to try to use it exclusively to charge my personal cell phone.
I also dropped all of this into a clear Pelican case. The solar panel still has to be outside, but it’s well-built enough that it can take some bumps and scrapes. I had to drill through the case to bring the solar panel’s cable inside, but filled the opening thoroughly with hot glue, so it should be water-resistant, if not outright waterproof. Bonus.
The project cost about $100. True, you can get USB solar chargers online for that much already… but they generally don’t have the battery (or the water-resistance), which is the real genius of my device. It can sit at home in a window all day soaking up sunshiney goodness. When I get home at night, I plug the phone in, and bam, no waiting for a sunny day. The battery can story 2700mAh, while my main phone has 1500mAh, so on a full charge it can almost charge two of them. It’d take about 8 hours of full-on bright sunshine to fully charge the device, but since it’ll rarely be down to zero and my phone won’t need daily charging (it averages three or four days between charges), it should only need a couple hours a day.
Saturday I had plenty of charge in there, but in a foolish attempt to measure how much power the battery had stored, I dischaged it all and it was sitting at zero. Stupid me. But after another day spent picking farm fresh juicy sunlighty goodness, I was able to plug in my phone and charge it from 71% to full just like I normally would. Woo!
It was fun. I’m already looking towards a new project. One that’s seriously been on my mind is a personal UAV. That’s right: people make their own unmanned (as in, autopiloting… seriously, based on GPS) aerial vehicle, mostly to slap cameras on there and get neato pictures. Problems there are the cost, and that I don’t have a lot of room: the worthwhile ones need at least a token runway. Plus the FAA doesn’t like if you fly them over too large a distance. Oh well.