Pi4, Pi3, and Arbotix Pro mini tower

[drachels]

My spare time for robotics has been very limited the past five years due to maintaining four different plugins for the Moodle LMS and my wife's two very serious health problems. To make things easier on myself, I have put together a Pi mini tower to hold the boards I am using for development. The mini tower has a Pi4 on the bottom layer, then a Pi3, and on top is the Arbotix Pro.

After putting it together, I almost immediately removed the clear top so I could easily swap the power leads between the two Pi's.
The Pi3 runs the HROS1-Framework without any problems, as long as I do not upgrade the OS.
When running the framework on the Pi4 there are a few errors generated when compiling the code. I am still working on fixing the communications between the Pi4 and the Arbotix. Send (Pi to AR) seems to work, but I cannot seem to get anything back.
Sadly, due to appointments, I haven't even had time to turn it on for the past four days.

[LloydF]

Very nice Idea.
Much better than my tenny runner approach and turning more screws than my fingers would like. If you get any breaks on the pi-4 that would be fun to try. My HROS-1 is fully shelled and working but like you said, no upgrades out that don't need more work.

[KurtEck]

I have not touched my HR-OS1 for a very long time. As I have mentioned in some other threads, my guess is your issue with either upgrade or RPI4 communications, is either with how the code configures the USB Serial baud rate, might be different. My own Linux code for talking to hexapod found I needed to do things differently depending on OS or board. That is can I (and some cases must I) ask directly for B1000000 for baud rate, or must I ask for B38... and use a secondary value to actually get 1mbs.

It might also be a udev rules change needed? And I don't think so with RPI, I know with some linux and Teensy there was an issue that the system installed a modem manager which can get in the way.

Other things I would look at, are all of the normal stuff when things are not working. Things like does: dmesg | tail
command in a terminal window show anything interesting...

[drachels]

Thanks for the additional info to both of you guys. I know this is going to take me much longer than I had hoped. I took a course in C++ back in 1994 and then have not touched it since. Spent most of my time over the past 20 years working/using PHP.

Unfortunately, I think I have really been wasting my time here for the past few days. I have been trying to track down my Pi4 problems by using dxl_monitor code. Due to inconsistencies I switched from the Pi4 to the Pi2 in my HROS1. Believe it or not, the dxl_monitor code there is even MORE inconsistent! The rme code does seem okay, though.

Anyway, I will have to drop this for a few days as I have a couple of Moodle users with problems with a plugin that I maintain so I need to go fix that for them.