I'm planning a project where I need to control a lot of Arduino Unos from a single PC. I'll need to send commands to the Arduinos and receive responses, as well as have the ability to update each Arduino from the PC, preferably without Arduino IDE at some point. Connecting via USB is out of the question, as I have already tried this and got miserable results, in part because of the number of Arduinos I need to control. So now I'm considering connecting the PC to an ethernet switch and then from there connect each Arduino with an ethernet shield.

Which brings me to my questions. Are there any limitations I should be aware of, if I want to pursue this setup? Will controllings tens, or even a hundred, Arduinos at the same time be a problem? How about stuff like updating a specific Arduino on the network?

My current working prototype uses a Windows PC that connects to one of multiple Raspberry Pis, which then in turn communicates with a number of Arduinos via I2C, and updates them via USB. But if I'm able to do all this directly from the main PC to the Arduinos via Ethernet, that would be fantastic.

Thanks for reading, looking forward to any answers.

  • 2
    One Arduino, or a million Arduinos, it makes no difference.
    – Majenko
    Apr 4, 2019 at 20:59

1 Answer 1


With a lot of devices on the ethernet, you may want to consider a private wire that is dedicated to those devices. That is, a second ethernet port or a VLAN off a capable switch.

As the number of devices increases, and the number of simultaneous talkers increases, you will start getting contention. Chances are a modern switch can handle this to some extent, but you were not clear on how much traffic you are planning on sending, or how often each device talks, or if it is centrally coordinated (aka "polled") or just speaking whenever.

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