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RE: [Raspberry_Pi_4-Ham_RADIO] Light Pipes (was: Re: Powering the Raspberry & TNC)

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  • Roger Elmore
    That seems to be the concept of the LC-2.0, but it has a 1mm fiber rather than a MM s 62.5um so it s 16 times the diameter for more light output. And since
    Message 1 of 53 , Apr 4, 2013
      That seems to be the concept of the LC-2.0, but it has a 1mm fiber rather than a MM's 62.5um so it's 16 times the diameter for more light output. And since the panel side already has a lens, at less than a dollar each it would be worth not having to take a Dremel cutting wheel to the ends of LEDs to glue them to the fiber. I bit the bullet and have 15 LC-2.0 Bivar's on the way, it won't be the first time I've put something in the spare parts box that didn't work out.

      But the Bivar's spec sheet doesn't show how the other side is terminated (if at all), so it looks like I may still be measuring, milling and drilling some kind of shroud to hold the ends over the LEDs on the PI. Sure would be nice if someone had something folks could buy off-the shelf...
      Roger KJ4AJP

      > How about some old MM fiber patch cable (no ends) and shave the
      > tops off of some panel leds to scatter the light? Not very
      > modular, down and dirty.
      > Matt - N0GIK
      > >
      > > On a different note, has anyone experimented with light pipes
      > to bring
      > > the PI's LED status to the front panel of a chassis? I've used
      > the
      > > Bivar SLP3-450-100-F on a NHRC Micro repeater controller
      > previously
      > > but the LEDs on the PI are too close together for those. I was
      > > looking at the flexible Bivar LC-2.0 at the Mouser website and
      > was wondering if those might work.
      > > Any input from anyone?
      > > --
      > > Roger KJ4AJP
    • Jim Thisdale
      F.Y.I. Most computer mother boards have switch mode regulators on the board to make all the various voltages needed for the processor(s), memory, north & south
      Message 53 of 53 , Apr 14, 2013

        Most computer mother boards have switch mode regulators on the board to make all the various
        voltages needed for the processor(s), memory, north & south bridges, and various other hardware.
        Gamer & enthusiasts boards often tout how many regulators/phases they have.

        As for radiation, most of the noise is from the leads & tracks on the board of chips themselves,
        especially when they are unshielded. A 5, 3.3, or even 1.8 volt signal toggling on-off at a high
        rate can radiate quite a bit, with 32 or 64 bits wide all toggling at such high clock rates it will
        radiate a lot of hash.... Computers tend to generate & radiate a lot of hash that's one reason the
        better made ones have metal cases and metal shielding in key areas. The minor amount of noise/ripple
        out of the supply is miniscule compared to the hash from the computer it-self. If a supply is truly
        that noisy the noise/spikes on the power would be mistaken for data and foul up the processing.

        -Jim- N1JMM, KB1YPL_B
        Visit my Pi running ircddb, dvrptr, Apache & many other things:

        On 4/7/13 6:15 AM, JJ wrote:
        > On 13-04-07 05:49 AM, John B. Cundiff Jr. wrote:
        >> Every time any digital device switches from off to on it produces a small spike and every spike
        >> as harmonics or RFI ... you can never completely clean up the supply of a computer ...you must
        >> design the computer
        >> to live with the spikes and RFI.
        >> On 04/07/13, Ray Wells<vk2tv@...> wrote:
        >> John,
        >> It's more than just spikes.
        >> The National Semiconductor recommendation to "tame" the output of the LM2596 smps is to add a
        >> series inductor (10mH from memory) and a shunt capacitor. Whilst this may very well result in a
        >> power supply that will "please" the Pi, it will do absolutely nothing to suppress RFI, which
        >> requires techniques quite different from those that produce a clean DC supply. The problem is not
        >> insurmountable but would require some devotion to produce a supply that is both DC and RF clean.
        >> It can be done.
        >> FWIW, the problem, from a Pi perspective, isn't necessarily spikes. Some smps's produce a distinct
        >> sawtooth output under load and whilst there may not be any spikes, there may well be dips below
        >> the minimum working voltage of the Pi at the bottom of the sawtooth waveform.
        >> Don't believe for one moment that you can assess a supply as being "good" with a voltmeter,
        >> digital or otherwise. It is indeed a case where a picture is worth a thousand words and that is
        >> where the CRO plays its part. If you don't have a hardware CRO, use a soundcard based device.
        >> There is plenty of free oscilloscope software available online.
        >> Ray vk2tv
        >> On 07/04/13 18:03, John B. Cundiff Jr. wrote:
        >>> Wood not a simple choke ...maybe a torridal choke
        >>> suppress the spikes every one is worried about .
        >>> Put a big value filter capacitor afterwards .
        >>> Be a lot more portable .. simpler and ..eleganter etc.
        >>> On 04/06/13, Kerry McKenzie<kermck@...> wrote:
        >>> Guys
        >>> a rarely dumb question?
        >>> how hard is it to just get an old pc power supply AT or ATX ,.... who
        >>> cares either way,... you will get between 15 and 50 amps at 5 volts and
        >>> throw a couple of caps across it.
        >>> If you crow it,... it will be smooth
        >>> if you go to any computer repair shop they will possible give you as
        >>> many old ones as you want as most of them still work.
        >>> i have 4 or 5 in my workshop down stairs and use them for all sorts of
        >>> things and it so easy.
        >>> my 2 cents worth.....Kerry
        >>> PS Linux is still a bitch and I,m going nowhere with my projects ;-((
        >>> --
        >>> Kind Regards
        >>> Kerry McKenzie
        >>> PO Box 4492
        >>> Kirwan QLD 4817
        >>> Australia
        > yes, I agree...I use a vp-1020 satellite card in my computer and the P.S. noise is affecting the
        > sensitivity of the card....my ham antennas are more than 100 feet from the house due to the rf
        > racket produced by many switching power supplies in the house...even the darn router and cable modem
        > supplies were awful, so running as much as I can directly from my solar system 12v rail...but there
        > are just so many things nowadays that use these switching supplies it's hard to eliminate them
        > all...oh, and then there's a neighbors samsung plasma tv .. 300 feet away from here and it wipes out
        > my packet system when it's on...
        > grr...
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