Onno (VK6FLAB)

Anything and everything Amateur Radio and beyond. Heavily into Open Source and SDR, working on a multi band monitor and transmitter.

#geek #nerd #hamradio VK6FLAB #podcaster #australia #ITProfessional #voiceover #opentowork

  • 1 Post
  • 38 Comments
Joined 4 months ago
cake
Cake day: March 4th, 2024

help-circle
  • In answer to the post that was removed, finding places to discuss ideas is not something that you are alone in. I find myself on that same quest on a regular basis and find answers seriously lacking.

    I love encouraging and providing supportive responses to posts that come my way, but rarely do I discover places to share and test ideas.

    Having been online for a long time, I think some of it relates to difficulty in expressing ideas in text succinctly and as a result conversation often degenerates into misunderstanding and (for want of a better expression) name calling.

    I don’t curate my feed or subscribe to communities, other than to filter hate speech and its distributors.

    Feel free to ping me, and if I have something to contribute, I will. Public conversation only.





  • Yes and no.

    At the frequencies that HDMI operates, the path a signal takes can interfere with that signal. It’s why sometimes a cheap HDMI cable causes issues, where one certified for 4K or 8K doesn’t - the requirements to carry more information, means higher frequencies and thus better shielding.

    A connector is a potential location where signal can be affected if the connection between two conductors is poor.

    In general, less connectors and less joins will give you a higher chance of success and less chance of interference, but it depends entirely on what type of distance and signal you’re trying to send across it.

    In general, the shorter the connection, the less loss.

    It might be that a single longer cable is worse than a connector and a short cable.

    If you already have a connector and a HDMI cable, try it. If you have issues, start by reversing the HDMI cable. It won’t make the electrons reverse or anything like that, but the connection might be slightly different.

    If you have neither, I’d get a cable without a join. Buy from people who take returns.

    Budget will be the determining factor for most people.

    TL;DR; try it.





  • DRM is one potential reason, but not the only one.

    Content is licensed under specific conditions, resolution, audio tracks, closed captions, etc. Two organisations might have licensed the same title, but not the same conditions.

    You can see this clearly during the Olympics where some channels only have secondary rights, or only certain events, but only free to air, not online, etc.

    Added to that are marketing and exclusively deals and in the end it’s anyone’s guess what you actually end up with.










  • Yeah, it’s already on a pi, connected to my LAN and the USB port of the CNC. The switch is on a gpio pin.

    I need to automate the calibration of the three axis. In other words, tell the CNC to move a specific distance, then figure out how far it actually moved, update the number of steps per mm, rinse and repeat.

    To implement this, I have a known calibrated distance, a set of three 1-2-3 blocks, so I actually need to move until the switch closes, then ask the CNC how far it thinks it moved.

    I intend to run this several times because right now, doing it manually is giving me weird results and I’m trying to figure out the root cause of the error.

    So, I need to move an axis, interrupt the move if the switch is closed, and keep moving until the switch is closed.



  • I started down the bash path but came unstuck when I wanted to create a process that uses a single bidirectional serial port to write a move command, whilst reading the current location and checking to see if an end stop switch was closed to write a stop command.

    Ideally, all of it is interrupt driven, but I’m at a loss to see how I can do this with either Kermit or expect. Both appear to use a send, then wait for a response model, even if you can check for different responses.

    Of note is that the end stop is external to the serial communication, so I can’t check the same stream for that information.