I'm trying to connect five ultrasonic sensors (HC-SR04, to be exact) to an Arduino board to detect obstacles in five directions (four cardinal + one Z-axis). I read the datasheet on the HC-SR04s and the Arduino Uno as well, and found that the ultrasonic sensor draws 15mA when active, and the Uno can supply a max of 40mA through each pin and a total of 200mA from all pins.
Now since I don't have ten PWM I/O pins, I've thought that since I'll be firing the sensors all at once, one trigger pin is enough. The ECHO pins will go to a separate PWM pin for each module.
I have two concerns here (I'm just a beginner in electronics :)):
I'm going to supply power to each sensor off a 5V/2A BEC. So will this cause current overdraw from the Arduino PWM pins? If so, is there a workaround? Maybe a transistor-driven solution? (I've done a basic electronics course in college, but never had a chance to design one on my own.)
The second concern is regarding my trigger pin design. Will one pin be able to pulse five of the sensors, or will the current drop not let them fire (since they're all in parallel)? My guess is that it's only the voltage that's firing them up (assumption) and in parallel it would all be the same so it should work, right?
I searched around, but I only found information on connecting one sensor to the Arduino. I read something about running high-amp motors with Arduino by supplying the current through a battery so I think my first concern should be fine? But I'm not sure, and so I thought I'd ask here. Thanks!