Connecting Arduino UNO to Raspberry Pi 4

[Jcoop920]

Hi, I was looking to see if I could connect 9 Arduino UNOs to a Raspberry Pi 4?

[horace]

you could try plugging the UNO USB cables into the RPi USB ports (would require a USB expander for 9 UNOs)
each UNO would create a virtual serial port which you could access as /dev/ttyUSB0, /dev/ttyUSB1, etc
what programs were you planning to run on the RPi?
give more details of the overall project?

[UKHeliBob]

Welcome to the forum

What type of data do you want to pass between the Pi and the Unos and why so many Unos ?

Bear in mind that the Uno GPOI pins operate at 5V whilst the Pi operates at 3.3V

[Jcoop920]

Thanks, I am trying to run motors on the arduinos and run an ai camera on the Pi 4.

[horace]

how many motors/UNO?
how far apart are the UNOs?
how are you powering the system?

[horace]

@Jcoop920

I am trying to run motors on the arduinos and run an ai camera on the Pi 4.

as a quick check I connected nine ESP32 board to a RPi 3B+

ran the following Python program

import serial
from serial.tools import list_ports

if __name__ == "__main__":
    for port in list_ports.comports():
        if "USB" in port.hwid:
            print(f"Name: {port.name}")
            print(f"Description: {port.description}")
            print(f"Location: {port.location}")
            print(f"Product: {port.product}")
            print(f"Manufacturer: {port.manufacturer}")
            print(f"ID: {port.pid}\n")

which displayed

raspberrypi:~ $ python3 ListCOMports.py
Name: ttyUSB6
Description: CP2102 USB to UART Bridge Controller - CP2102 USB to UART Bridge Controller
Location: 1-1.2.4
Product: CP2102 USB to UART Bridge Controller
Manufacturer: Silicon Labs
ID: 60000

Name: ttyUSB5
Description: CP2102 USB to UART Bridge Controller - CP2102 USB to UART Bridge Controller
Location: 1-1.2.5.7
Product: CP2102 USB to UART Bridge Controller
Manufacturer: Silicon Labs
ID: 60000

Name: ttyUSB3
Description: USB2.0-Ser!
Location: 1-1.2.7
Product: USB2.0-Ser!
Manufacturer: None
ID: 29987

Name: ttyUSB4
Description: USB Serial
Location: 1-1.2.6
Product: USB Serial
Manufacturer: None
ID: 29987

Name: ttyUSB2
Description: USB Serial
Location: 1-1.2.5.6
Product: USB Serial
Manufacturer: None
ID: 29987

Name: ttyUSB1
Description: CP2102 USB to UART Bridge Controller - CP2102 USB to UART Bridge Controller
Location: 1-1.2.5.5
Product: CP2102 USB to UART Bridge Controller
Manufacturer: Silicon Labs
ID: 60000

Name: ttyUSB0
Description: USB Serial
Location: 1-1.4
Product: USB Serial
Manufacturer: None
ID: 29987

Name: ttyACM1
Description: Feather RP2040 CAN - Board CDC
Location: 1-1.2.3:1.0
Product: Feather RP2040 CAN
Manufacturer: Adafruit
ID: 33071

Name: ttyACM0
Description: USB Single Serial
Location: 1-1.5:1.0
Product: USB Single Serial
Manufacturer: None
ID: 21971

a Java terminal emulator displayed

[Jcoop920]

Thanks!