Question with circuits

Hi,

Hello,

Im experiencing an issue and/or curious of what design I should take moving forward with my intended goal.

I recently just bought a Arduino 101 board trying to improve computational power and reduce energy consumption while gaining the gyro and such over my other uno board (v3).
I am trying to create an autonomous quadracopter with six ping sensors for each axis of view (front, bottom, left, right,...) and am running into an issue as the 101 board runs on 3.3 volts.
The cheap 4-pin ping sensors require a 5V power source which I can run from Arduino but will quickly exceed its current supplying capabilities when I use 6 sensors at once in range mode.
I have bought a buck converter to efficiently reduce the quadracopter's voltage (battery) down to a safe 5V to supply the Ping sensors.
My question concerns powering the ping sensor with one source from the regulator and then transmitting/receiving signals with the Arduino board.
m hoping I can tie the grounds together between the two but I don't know what issues this may cause concerned of different ground potentials.
One battery btw will be supplying both the regulator to ping sensor and the Arduino board which has its built in regulator.

If tying the grounds together is a bad option.
How can I run 6 ping sensors at their proper 5V potential without overloading the current capabilities of the Arduino board (20ma) and still having room on the Arduino board for transmitting and receiving signals.
Pin space is a premium as I not only need to power and communicate to these ping sensors but power the four motors through an H-bridge setup.

Thank you for your time and help!
Ada

Sorry but it needed to be edited to make the entire post readable.

Tom... :slight_smile: