I control a BeagleBone Black remotely using VNC or SSH. That is fine, but sometimes when I am close to the machine I want to see a simple GUI to check something. Currently that is done by connecting a Rasperry Pi with Ubuntu in the room and then VNC’g into the BBB. This is pretty inconvenient.
I am keen not to give up the pins needed to activate the HDMI port. I would like to connect a monitor through the USB port. I’ve seen discussions of USB port displays for Ubuntu, but support for LInux and Debian in general seems low. Also, everything I have seen is assuming USB3.0
Has anyone had success doing something similar? Speed and resolution are not critical here, the VNC connection through the Raspberry Pi is super low.
You won’t be able to do USB to monitor on a BBB. That’s not to say you can’t find some sort of serial over USB type display. There are plenty of LCD panels of various sizes to be found on AliExpress that use an SPI port to update the display assuming you have a spare SPI port. That probably wont be a seamless interface to whatever you are running. currently. You will need to write some software to write to the display to show whatever data you want to view. There are some simple GUI libraries that can be used though to generate a frame buffer that you can then write out via SPI.
Hi There…I was hoping to eliminate the RPi. Nothing against them, but in a factory setting any time you can eliminate network resources the better. If I could have a USB monitor, that is a passive device. I’ll look into Benedict’s suggestions, but I was naively hoping to find a solution where I did not have to design an interface board. If you saw how laggy the VNC connection was, you would see that the baseline is pretty terrible! Thanks for the suggestions…Alan
@AlanMThomason , Seth here. I have found that you can only power, via 5v, a LCD Cape or other LCD Screen from the BBB USB port to the Cape or LCD Screen.
If you want to supply a LCD Screen of your own, outside of the Capes available, using the peripherals on the am335x on the BBB makes this available w/ LCD pins that are dedicated and SPI pins too.
Those are solely my ideas though.
Seth
P.S. Enjoy making this work. There are plenty of knowledgeable people here that have done things like this idea you are focusing on. FYI, I have not been able to just use a USB port for a LCD Screen so far. Only for powering it cheaply…
I assume due to your other posts this BBB is running linuxcnc and that is what you wish to view.
There are several ways you can go and a lot will depend on just what you want to see on the display.
If you just want some sort of status and you can get the info you could certainly display this on a small display. Make up a custom gui using something like LVGL
If you want to display the linuxcnc gui, that would also be possible. You could do a screen shot to grab an image and then convert and send it over SPI to a display.
Either way the update will be at best maybe 10 fps depending on resolution, colour depth and SPI speed. That’s assuming you have the spare CPU cycles.
While you can send large blocks of data over SPI using spidev, you will still need to break a screens worth of data into multiple calls.
You are in effect doing what VNC does, only to a local SPI display, rather than over a network. Obviously your best option would be to use HDMI, but if you can’t spare the lines you have limited choices.