user71313: I am building a robot snake with a bunch of servos and ov7670. As I see, ov7670 operate with 3.3v and servos needs 5v. I will use Lipo battery for servos for this I need to connect ground pin of arduino and input of battery. But For ov7670, I already connect the ground pin of arduino. Can I connect ground with a jumper to another breadboard to connect with lipo battery and servos or I need two arduino nanos?

user521: You can use a common ground in fact it's the normal thing to do with external circuits such as relays, servos etc

71313: <p>I am building a robot snake with a bunch of servos and ov7670. As I see, ov7670 operate with 3.3v and servos needs 5v. I will use Lipo battery for servos for this I need to connect ground pin of arduino and input of battery. But For ov7670, I already connect the ground pin of arduino. Can I connect ground with a jumper to another breadboard to connect with lipo battery and servos or I need two arduino nanos?</p>
 521: <p>You can use a common ground in fact it's the normal thing to do with external circuits such as relays, servos etc</p>
