arm-netbook August 2017

arm-netbook@lists.phcomp.co.uk

23 participants
32 discussions

physics analysis needed of belt-driven pulley system
by Luke Kenneth Casson Leighton 29 Aug '17

29 Aug '17

some background: http://forums.reprap.org/read.php?177,767087,784083#msg-784083 and the same question here: https://physics.stackexchange.com/questions/352661/ can anyone help? basically - and i really should have done this before going ahead... *sigh*... - when you have a pulley system is the amount of force on the belt less, equal, or greater, under the same *print-head* acceleration conditions, compared to a *non* pulley system? l.

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m
by Richard Wilbur 25 Aug '17

25 Aug '17

Sent from my iPhone

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http://rhombus-tech.net/allwinner_a10/news/
by Luke Kenneth Casson Leighton 24 Aug '17

24 Aug '17

ok so i did a quick summary (despite the length) of the status so far... i hope there is light at the end of the tunnel.... --- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68

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frickin funny
by Luke Kenneth Casson Leighton 15 Aug '17

15 Aug '17

https://motherboard.vice.com/en_us/article/78w8jy/pcmcia-once-defined-porta… i had no idea this article existed... i absolutely love the conclusion.... --- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68

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PCB Collaboration and Revision
by mike.valk＠gmail.com 14 Aug '17

14 Aug '17

https://hackaday.com/2011/10/14/hardware-version-control-using-visual-diff/ http://www.evilmadscientist.com/2011/improving-open-source-hardware-visual-… For the next project

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riki200 revision.... 2 going on 3
by Luke Kenneth Casson Leighton 14 Aug '17

14 Aug '17

ok so the intermediary etch-a-sketch concept "works", but i'm definitely going to go for the design you came up with, benson: pulley'd ultimaker-2. actually.... reviewing the forum messages the mistake that i made was in *not* following what you originally suggested! http://forums.reprap.org/read.php?177,767087,780154#msg-780154 putting the 2 belts back-to-back round the idler and GT2, it's now obvious that the inner and outer belts travel different lengths round the arcs... so you get "pulling". whoops. anyway out with that - i'll begin on the pulley-augmented ultimaker style. l.

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severe systemd bugs (two of them)
by Luke Kenneth Casson Leighton 12 Aug '17

12 Aug '17

https://it.slashdot.org/story/17/07/03/0343258/severe-systemd-bug-allowed-r… two years. that's how long one of these bugs has been in systemd. *via a remote network*. what the hell is an init system doing being accessible *via DNS queries*? for anyone who still believes that systemd is okay to use and deploy, and that there exist "great advantages that outweigh the risks", are you *finally* getting the message now? dozens of distros, millions of people, all affected by the irresponsible act of switching "en-masse" to a single over-reaching init system which is developed in a fashion that is not being properly managed or controlled. i do not understand why people do not understand this. l.

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Eoma68 update
by Joseph Lira 12 Aug '17

12 Aug '17

Hello >From your last update I havent seen an update as to how the os will be delivered/installed can you give an update? Will it be an SD card? Also when do you plan to start shipping boards the crowdfunding says nov of this year is that still correct? Im asking becuase i wanted to use the eoma68 to be a little low power stream box actually can this be done? Or i wanted to replace my original pi that runs pi-hole I been very temped to buy a new raspberry pi 3 for streaming or a tiny intel nuc to do the same, but i held of because i truly want to support your project

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HDMI High-Frequency Layout: Recommendations
by Andrew Bolin 11 Aug '17

11 Aug '17

>> Also I'd personally not use curved wriggles. HF signals travel in a >> straight direction. With curves they start diffracting and start >> bouncing cross each other and might start to radiate or echo back. > > mmmmm.... *stress*! anyone else feel the curves are "Bad"? No. You've followed a bunch of very good advice about length matching, impedance etc. It looks like you've generally kept the pairs parallel through the curves, which is great. If you have an easy option in your software to switch from 45 degree corners to smooth curves, I would do it - if there's not, don't worry. >> If tight for space you can use 90% corners with a chamfered outer >> edge. I suppose the chamfer acts like a mirror. The chamfer is there for impedance reasons, it's not a mirror, and note that a curve is preferred. You also run the risk of manufacturing problems by doing the chamfer - you're already at the minimum trace width, right? As you've previously said, the old layout was further away from best practices, and *it worked*.

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my favourite dilbert... evvah!
by Luke Kenneth Casson Leighton 10 Aug '17

10 Aug '17

http://dilbert.com/strip/1994-02-06 still beautifully relevant today....

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arm-netbook August 2017