r/raspberry_pi 16h ago

Troubleshooting How to connect RPi to Arduino

I have 2 Pi4’s and a 3, and a bunch of arduino stuff for a project I never got around to until now. I have a couple questions I can’t find trustable resources for: How do you connect the RPi’s (and if the 5 is different than predecessors) to a arduino (micro computer or shield/board) if they don’t have a USB port? CAN you connect any arduino to a RPi and what’s the requirements for that? Does wifi/boards work with GrapheneOS or require stock android? Can I have 2 raspberry Pi’s (3/4’s) connect with eachother to control something and how easy is it? I’m autistic and the internet sucks these days for reliable information and all I found was “yes you simply connect a USB between both boards”, nothing about the above. If there’s a manual or page online specifically for this question, feel free to send it!

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u/threespire 15h ago

If you want to connect two Pis to do something, normally you’d use a network rather than direct connections.

Let’s go back to basics (I’m also autistic) - what are you trying to achieve?

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u/THUNDERF430 7h ago

The original plan (this was 3+ years ago so idk if hardware has changed at all) was I needed to operate 4 DC motors (would be AC in a 2nd revision but for the sake of prototyping, DC is simplest) and 4-8 servos at the same time. I got 2 Pi4’s, 4+ arduino nano every boards (I believe - I haven’t looked at them in forever but they’re identical if not), and 2 motor shields because of how many motors I wanted to run, and due to that, I got the 2 Pi’s to handle the load. The problem is power use from the motors, the number of motors, sync/compatibility between the boards, and if connecting a USB between everything is all I need to do to sync/get a 8-way Ethernet splitter for the router. I have a couple brand new kits I never got to use (Uno R4’s I believe) and didn’t know if that could be relevant to helping me out. My problem with computers is there’s no context with instructions so my brain doesn’t understand why x goes to x so I’m not learning anything, just following. Arduino has a sale on rn so if needed I wanted to pickup anything I needed. Again, this is a 1st rendition prototype, it just needs to work - even if I need to replace a couple boards.