Verified answer

It works as a vocoder.

I've never been able to get it to work though.

Yes, both temperature and humidity affect your guitar tuning, but they may not be the only cause of the problem you describe. Temperature and humidity cause the wood components of your instrument to expand and contract. This is easily demonstrated if you ever tune up then immediately drive to someone else's home. Let your guitar sit for a about an hour and chances are it will need to be tuned again. If you'd left it in the same spot in your own home, it would probably be fine. I'm not recommending that you subject your guitar to such tests, by the way. The more stable the environment, the happier your instrument will be. In addition to the problem you've already noticed (the stretching and relaxing of your strings caused by the body expansion and contraction) repeated temperature and humidity cause other problems. The joints, glue, braces, and other parts of your instrument are also affected. In general, keep your guitar in a stable environment whenever possible. The other problem you may have is old strings. Problems keeping your guitar in tune is a classic sign of strings that have lost their resilience and should be replaced. For more information on guitar strings, maintenance, and how humidity affects your guitar, see the sources, below.