[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xylo-SDR] Some design thoughts requested


It's thinner than a standard 0.062" thick PCB - don't remember if it's 0.031 or 0.050,
but being thinner limits the number of layers that are practical.

We were using SODIMM format cards in a similar fashion at my previous employer
and found that the PCB's/sockets were good for only a limited number of insertions.
OK if you pick out a set of modules and assemble a unit once, but not a good
connector choice for experimenters.

John KK6IL

At 04:11 PM 1/3/2006, you wrote:
One advantage of the DDR size card is that if you don't need a large card it could be the size of a DDR module which is pretty small. You could fit a SR5 and the bandpass module in one stick and still have a little room.

There is a board thickness that you need to maintain in order to get good contact to the socket, I don't have calipers at home to measure the thickness of a DDR card, and see if that is a standard thickness.

At 05:50 PM 1/3/2006, you wrote:
Guys
 
Done!
 
Lets go DDR DIMM sockets? with a MB of our design.  Now (or first) we need an extruded aluminum (or other) project case with slides, in the size we are talking about so we can define the board real-estate as default to slide in the enclosure. Space on every few rails for a faraday shield between boards.  The PCI bus gave us cheap L-Brackets on a third side for connectors, however in this design everything must come out the ?front? of the box. It would be nice if we could design a ?front? panel based on a PCB which could be drilled for common connector sizes and be reproduced for different projects. Heck, even a blank buss structured, motherboard, power distribution, project case of this sort could be a product with all the experimenters around!
 
Sell this and fund our xylo boards! (smile)
 
Comments?
 
Eric
 
 
 
 
From: xylo-sdr-bounces@lists.ae5k.us [ mailto:xylo-sdr-bounces@lists.ae5k.us] On Behalf Of KD5NWA
Sent: Tuesday, January 03, 2006 2:44 PM
To: Xylo-SDR Discussion
Subject: Re: [Xylo-SDR] Some design thoughts requested
 
That is workable for small boards, with .05" (1.27mm) pin spacing it's very doable even with homemade PCB boards.

Boards 5.5"x3.5" would be a reasonable board size, and with todays components you can put a whole lot of circuitry in a board that large.

I've seen someone build a little jig to use a router to route the connector and a belt sander to bevel the edge connector  at home.

I have not been able to find ready-made prototype boards.

I've found an interesting source of IC header boards, reasonable when you consider the quantities you get.
P516 and P507 look interesting.

< http://www.beldynsys.com/singledual.htm >


At 12:11 PM 1/3/2006, you wrote:

Hello all,

I considered using DDR SIMM sockets for a project.  You get 184
contacts and they give you a card width of 5.25".  The height of the
card is not restricted (within reason).

http://www.molex.com/pdm_docs/sd/876362002_sd.pdf

It is kind of like the SIMMStick idea, but with more contacts (184 vs
30).  30 pin SIMM sockets are very hard to get these days and I see
that Molex has scheduled the 72 pin SIMM sockets for obsolescence.
The DDR DIMM sockets should be around for a while yet.  They are
relatively cheap ($1.92 ea Digikey).

73 de Phil N8VB


On 1/2/06, Eric Ellison <ecellison@comcast.net> wrote:
>
>
>
> Cecil
>
>
>
> Yes, I'll go back and look at Eurocard standard. This looks great. GUD
> HUNTING! Thanks for all the links. One way or tother I think we need a buss
> for our end product. Your point about size of the boards we might want to
> manufacture is well taken. They should be able to go on a little more than a
> postage stamp, and be VERY inexpensive to produce - external connectors
> being the limiting size factor! One reason I was looking at Memory Chip
> risers.
>
>
>
> I moused around a little today, and really can't see where I can justify
> Eagle Software in any serious production version. So I'll probably monkey
> around with Kicad, which is a really nice GPL product. I mentioned earlier
> that there was some problem with the Drill files, which they have corrected.
> Only benefit of Eagle IS the plethora of template files available. I don't
> mind eating on my lunchtime and creating new parts! Good exercise and I am
> getting fatter! (No Testosterone!)
>
>
>
> Sparkfun has a pretty good batch deal for prototype boards and also a lot of
> interesting new products. I like their little 3 buck power supplies. Also
> have a some 28 pin SOIC to DIP experimenter stuff for about the same price.
>
>
>
> http://www.sparkfun.com/shop/index.php?shop=1&cart=525299&cat=1&PHPSESSID=abce58b426cb8d0d0c3cf4b1495f0312
>
>
>
> Other prototype boards can be had at:
>
>
>
> http://protoboards.theshoppe.com/index.html
>
>
>
> Will return!
>
>
>
> Viva the Project
>
>
>
> Eric
>
>
>
>  ________________________________
>
>
> From: xylo-sdr-bounces@lists.ae5k.us [ mailto:xylo-sdr-bounces@lists.ae5k.us]
> On Behalf Of KD5NWA
>  Sent: Monday, January 02, 2006 2:06 PM
>  To: Xylo-SDR Discussion
>  Subject: Re: [Xylo-SDR] Some design thoughts requested
>
>
>
>
> I'll second the DIN connectors,they are very reliable, and come in different
> sizes, single, and dual connector cards. I have used them in an industrial
> environment and they worked flawlessly for years. But I'll go one more step
> forward.
>
>  The Eurocard standard allows for mix of one 96 pin connector,  two
> connectors or even three connectors (not needed). Prototype boards are
> cheap, most PCB houses have specials on Eurocard size boards. Card cages are
> available for low prices for the Eurocard format
>
>  Like Leon said the connectors are expensive but they are self aligning, and
> I've seen then for under $3 on the Internet.
>
>  Although the PCI is tempting and cheap for the backplane, it's a bus that
> is designed for digital logic, all pins are tied to the same pins in all
> cards. Prototype cards tend to be large and expensive.
>
>  A brief blurb on Eurocards;
>
>  < http://www.yotor.org/wiki/en/eu/Eurocard.htm >
>
>  Cheap prototype boards are available for $10 or less, a very important
> point, $50 to $60 for a PCI card is very expensive, maybe I'm too cheap, but
> the blank board should not cost more than the components.
>  < http://www.sbszoo.com/ve6sbs/sale/cct-brds.htm >
>
>  Here are some available at Mouse;
>  <
> http://www.mouser.com/index.cfm?handler=data.getPcodes&pcode=BPS%2BPrototype%2BBoards&pcodenumber=85400
> >
>
>  Sample enclosure, can be home made from aluminum extrusions.
>  < http://www.busboard.net/bps-enc.htm >
>
>
>
>  At 03:34 AM 1/2/2006, Leon Heller wrote:
>
> ----- Original Message -----
>
> From: Eric Ellison
>
> To: 'Xylo-SDR Discussion'
>
> Sent: Monday, January 02, 2006 5:17 AM
>
> Subject: [Xylo-SDR] Some design thoughts requested
>
> Folks
>
>
>
> Even since the PIC 4550 days I have been thinking on how we might conduct
> experiments as well as have a reasonable environment for addingon to the
> project. The obvious answer is a buss of some sort. I have looked at
> everything from Simm riser boards to ISA buss stuff. PCI risers might be the
> way to go since they are inexpensive ($15) for 3 slot extenders. Also in an
> end product they fit into the L-brackets of a computer case, or 2U mounts.
> They have assignedpower busswe can use, fairly inexpensive prototyping
> boards. ($50 - $60), are four layer and designed to minimize intra trace
> noise. The buss wouldnt be used for PCI, however it would allow power, (on
> designated standards based lines), intra board connections, and FPGA,
> I2C,signals etc.
>
>
>
> PCI seems to be a little largefor what we are proposing, and the product
> boards would cost more to produce, however, with an established buss we
> could put a radio on one card, FPGA on another Audio on another etc.
>
>
>
> $15 Board amongst others:
>
>
>
>
>
> http://www.plinkusa.net/riser.htm
>
>
>
>
>
>
>
>
>
> Am I off the wall here?
>
>
>
> That's the sort of thing I was thinking of doing. I used to work for Racal
> and they used to build their military radios from separate screened plug-in
> modules on a backplane.
>
>
>
>  I favour DIN41612 connectors for this sort of thing. They are expensive,
> but very reliable, and have pins on 0.1" centres. They can even accomodate
> co-axial connectors. They are more commonly used in Europe than the USA, but
> you can get them over there without any problems.
>
>
>
>  73, Leon
>
>  --
>  Leon Heller, G1HSM
>  leon.heller@bulldoghome.com
>  http://www.geocities.com/leon_heller
>  _______________________________________________
>  Xylo-SDR mailing list
>  To post msg: Xylo-SDR@ae5k.us
>  Subscription help:
> http://lists.ae5k.us/listinfo.cgi/xylo-sdr-ae5k.us
>  Xylo-SDR web page: http://xylo-sdr.ae5k.us
>  Forum pages: http://www.hamsdr.com/hamsdrforum/
>
>
>  Cecil Bayona
>  KD5NWA
>  www.qrpradio.com
>
>  "I fail to see why doing the same thing over and over and getting the same
> results every time is insanity: I've almost proved it isn't; only a few more
> tests now and I'm sure results will differ this time ... "
> _______________________________________________
> Xylo-SDR mailing list
> To post msg: Xylo-SDR@ae5k.us
> Subscription help:
> http://lists.ae5k.us/listinfo.cgi/xylo-sdr-ae5k.us
> Xylo-SDR web page: http://xylo-sdr.ae5k.us
> Forum pages: http://www.hamsdr.com/hamsdrforum/
>
>
_______________________________________________
Xylo-SDR mailing list
To post msg: Xylo-SDR@ae5k.us
Subscription help: http://lists.ae5k.us/listinfo.cgi/xylo-sdr-ae5k.us
Xylo-SDR web page: http://xylo-sdr.ae5k.us
Forum pages: http://www.hamsdr.com/hamsdrforum/


Cecil Bayona
KD5NWA
www.qrpradio.com

I fail to see why doing the same thing over and over and getting the same results every time is insanity: I've almost proved it isn't; only a few more tests now and I'm sure results will differ this time ...
_______________________________________________
Xylo-SDR mailing list
To post msg: Xylo-SDR@ae5k.us
Subscription help: http://lists.ae5k.us/listinfo.cgi/xylo-sdr-ae5k.us
Xylo-SDR web page: http://xylo-sdr.ae5k.us
Forum pages: http://www.hamsdr.com/hamsdrforum/


Cecil Bayona
KD5NWA
www.qrpradio.com

"I fail to see why doing the same thing over and over and getting the same results every time is insanity: I've almost proved it isn't; only a few more tests now and I'm sure results will differ this time ... "
_______________________________________________
Xylo-SDR mailing list
To post msg: Xylo-SDR@ae5k.us
Subscription help: http://lists.ae5k.us/listinfo.cgi/xylo-sdr-ae5k.us
Xylo-SDR web page: http://xylo-sdr.ae5k.us
Forum pages: http://www.hamsdr.com/hamsdrforum/
Internal Virus Database is out-of-date.
Checked by AVG Anti-Virus.
Version: 7.0.344 / Virus Database: 267.10.12/75 - Release Date: 8/17/2005