I was making a robot with a raspberry pi 4 which will have four ultrasonic sensors on all its four sides..
I was looking up in google to see the schematic of the connections and noticed that there are 2 resistors connected to the echo pin.
Image Source: https://tutorials-raspberrypi.com/
Note that the image has a raspberry pi 3 but I am working with a raspberry pi 4
I do understand that the resistor is kept to limit the current, but my first question is that will it work without the resistor and is it a must for the resistor? The ultrasonic sensor works fine with the 5V output pin from an Arduino without any resistors, so it should work fine with the 5V of my raspberry pi 4 also right?
Now to my second question..
I want to connect 4 ultrasonic sensors to my rpi4, so should I connect the resistors to all the echo pins of the ultrasonic sensors?