...And even if you don't pursue Indian music per se, you might look into acquiring an electronic tambura.
The tambura is a stringed instrument that's used to provide the accompanying drone for a soloist. The electronic tambura is basically a simple synthesizer to provide drones for practice, though I once saw a sitarist use a high-grade electronic tambura in concert.
I inherited a 1970s-vintage model from a colleague who plays sitar (he has a newer, spiffier model). The tone isn't lovely, but you can choose whether the drone includes one, two, or three pitches, and you can fine-tune the different tones individually.
It's great for basic intonation exercises... certainly easier than trying to hold a pitch pipe between your lips as you glide among pitches.