For me, the biggest stumbling block to learning to play the guitar was consistently keeping the instrument in tune. A seasoned player can tune up his or her ax by ear, but for the rest of us an electronic tuner is the best bet. I've been through a few models in my 20+ years of noodling, and Tascam's TC-1S solar-rechargeable tuner is the best I've owned by far. (And no, they didn't pay me to say that.)
Here's Tascam's sales pitch:
The TC-1S charges its battery from a bank of solar cells on the front panel in just 25 minutes, and a USB input is also available for quick-charging. From a full charge, the battery works for six hours of constant use and seven years of standby charge in a dark place. It's wrapped in a shock-proof silicone cover that's available in six colors and keeps the unit protected.
The TC-1S has a built-in microphone as well as a 1/4" input for guitar and bass tuning. Its lightning-fast pitch detection is displayed on a wide bargraph display for instant feedback. Four display modes are available, including fine pitch display for 1-cent accuracy and strobe tuning animation. The tuner can be calibrated to an external source such as a piano or other hard-to-tune instrument
The display is the easiest to read that I've seen on a tuner and even without the protective cover the unit seems very sturdy.
But, the best part is that its battery is charged by the sun! Plus, it holds a charge for a long time. I've had mine for six months stored deep in a junk drawer and it's always charged when I fish it out.
Now, admittedly, an instrument tuner isn't something that draws continuous power and even regular old battery powered models will remain powered with one set of batteries for a long time. But, I'm so often disappointed by solar powered gadgets that don't deliver on their promise of being powered by the sun that Tascam's application of solar tech has me pretty jazzed.
If you're in the market for a tuner for yourself or looking for a gift for a budding musician, do yourself a favor and buy the Tascam TC-1S. It comes in six colors for under 40 bucks wherever Tascam gear is sold.