[TriEmbed] Fwd: [Splat Space] Re: PCB design software

Wed Aug 17 20:57:05 CDT 2016

Hey Scott,

I agree.  There are a lot of complexities that current autorouting software
does not adequately address.  Some of these problems can be addressed by
adding handles for them in the autorouting software (additional cost
associated with being near this group of traces).

Others are harder to handle and a good fix does not come immediately to
mind (though I have some possible avenues of research).  However, I am not
trying to build a general solution.  I am trying to make something that
lets me wire up a microcontroller with its supporting hardware/serial
interfaces and sensors quickly.  Most of the lines will be pretty low
frequency (CANBus is the sole exception), so I think that many of these
issues will not be that bad.  Goodness knows I am not accounting for them
when I am routing my current boards (apologies to all hardware
professionals).

Do you think that these issues will be significant in simple Arduino style
applications?

Thanks,
Charlie

On Tue, Aug 16, 2016 at 4:24 PM, Scott Hall <scottghall1 at gmail.com> wrote:

> Charles,
>
> One of the difficulties I've had with PCB routing and layout in the past
> is considering crosstalk between traces.  You have to consider if similar
> signals are on adjacent traces and whether signal levels at that point are
> strong enough to induce inductive currents between them.  In audio you can
> hear this as two disparate channels having a low-level "ghost" of the other
> channel present.  Another consideration is the frequencies involved and the
> shape of the traces -- sharp corners tend to radiate RFI at higher
> frequencies.  Routing different segments in different shapes using
> different lengths and possibly adding ground or power traces between them
> or routing them at angles to each other helps with these two problems.
> Then you can introduce timing differences between parallel signals -- think
> how the Olympic tracks have a staggered start for lanes to compensate for
> larger distances on the outside lanes.  You may need to add an S curve to
> sync things up again.  Finally consider the width (and thickness) of traces
> per the currents that they will have to handle.  Most folks underestimate
> trace losses with routing power (Vcc) and ground (Vdd) signals.
>
>
> On Mon, Aug 15, 2016 at 7:17 PM, Charles West <crwest at ncsu.edu> wrote:
>
>> Just a quick mention.  I'm currently working on an open source
>> auto-router, if anyone is interested in that sort of thing.  Too early to
>> tell how useful it would be (but I think I am bad enough at PCB design that
>> it wouldn't be that hard to do better).
>>
>> Gonna start with a JSON/text based format and use A*/shortest path first
>> routing with an off the shelf gradient free optimizer for component
>> placement.  We'll see if it is any good in a few months.
>>
>> Thanks,
>> Charlie
>>
>> On Mon, Aug 15, 2016 at 6:53 PM, Shane Trent via TriEmbed <
>> triembed at triembed.org> wrote:
>>
>>> The latest Free version of Eagle Supports two schematic sheets. It is
>>> also for non-commercial use.
>>> https://cadsoft.io/pricing/
>>>
>>> Eagle PCB was recently purchased by Autodesk.
>>> http://hackaday.com/2016/07/05/the-future-of-eagle-cad/
>>>
>>> Shane
>>>
>>> On Mon, Aug 15, 2016 at 6:30 PM Robert Gasiorowski via TriEmbed <
>>> triembed at triembed.org> wrote:
>>>
>>>> With free version, you can create 2 layer, 100mm x 80mm boards.
>>>> You can only have one schematic sheet, but it is pretty much unlimited
>>>> in size.
>>>> Also, you can create boards that are larger than 100mm x 80mm with free
>>>> version, but it requires some trickery.
>>>>
>>>> Rob.
>>>>
>>>> On Mon, Aug 15, 2016 at 6:06 PM, Scott Hall via TriEmbed <
>>>> triembed at triembed.org> wrote:
>>>>
>>>>> Over the last year or so the TriEmbed group has had this very
>>>>> discussion.  So I am cross-posting this to TriEmbed's discussion so that
>>>>> folks can reiterate the information.
>>>>>
>>>>> ---------- Forwarded message ----------
>>>>> From: Ian Baillie <mountainman28753 at gmail.com>
>>>>> Date: Mon, Aug 15, 2016 at 4:57 PM
>>>>> Subject: [Splat Space] Re: PCB design software
>>>>> To: Splat Space <durham-makerspace at googlegroups.com>
>>>>>
>>>>> On Monday, August 15, 2016 at 2:14:48 PM UTC-4, bill wrote:
>>>>>>
>>>>>> Can someone give me the quick rundown of Eagle PCB design software? I
>>>>>> was thinking it was free but it appears that it is limited restricted based
>>>>>> on various design requirements,
>>>>>>
>>>>>> If I need to make some simple two sided boards, what version of the
>>>>>> software would I need? Can I produce schematic files to send to a fab shop
>>>>>> with the free version? What are the restrictions?
>>>>>>
>>>>>> I appreciate any help offered.
>>>>>>
>>>>>> Thanks.
>>>>>>
>>>>>> Bill
>>>>>>
>>>>>> Look into Kicad, that is the software we've been using at our space
>>>>> (Asheville), with good results. It is actually free, instead of partially
>>>>> free. Prior to that, we used Eagle. Just.my .02
>>>>>
>>>>> --
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>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Scott G. Hall
>>>>> Raleigh, NC, USA
>>>>> scottghall1 at gmail.com
>>>>>
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>>
>
>
> --
> Scott G. Hall
> Raleigh, NC, USA
> scottghall1 at gmail.com
>
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