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

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Joined 9 months ago
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Cake day: March 4th, 2024

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  • Seriously? From the README:

    I would like to first fix the kernel headers issues that break the UAPI for C++ compilers (because they use C++ keywords that break C++ code) and the Windows filesystem (Windows filesystem is case-insensitive, so some headers cannot be stored on Windows filesystems).

    I can’t wait to see this kernel become dependent on .NET

    If you’re wondering, this is what embrace, extend and extinguish looks like.











  • I don’t know, but I doubt that the frequency response of a mobile phone microphone is either linear or consistent across sound level.

    I don’t even think you could compare two sounds with different frequencies, but I don’t know.

    I suspect that calibration of any such thing would require a whole lot of infrastructure, consider for example the angle of the phone in relation to sound and the impact of holding the phone in how it affects vibration and noise damping.

    You might be able to use a calibrated sound level meter and pair it via Bluetooth with your phone, but I think that’s going to be as close as you might get.

    In the past I’ve tried a wired USB microphone, but the OS isn’t real-time, so the jitter was horrendous. A pi would give you a more consistent result.




  • 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.