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  • Author Author: Gough Lui
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When PCBs Are Cheaper Than Lunch, Build PCBs! A DA-15 & Banana to Terminal Block Breakout

Gough Lui

It wasn't all that long ago that I took the step to get myself acquainted with KiCad and start designing PCBs for manufacture in my spare time - in fact, just two years ago. But since then, I could not have imagined that vendors such as JLCPCB could build five two-layer 100x100mm PCBs and ship them to my house for between AU$8.50 to AU$9.00. For comparison, a McDonalds Small Big Mac meal runs about AU$11.90 as of today in this inflationary environment. This is something I could have never imagined, growing up making PCBs by hand and being told that a double-sided board was already a luxury. Now we get soldermask and silk-screening as part of the deal, along with delivery from China! Sure, it takes about two to three weeks to arrive, but that's a small price to pay for the big saving in shipping cost.

As a result, I spent a bit of time building some solutions to my small annoyances. The first is to do with the DA-15 connections on the back of R&S NGL/NGM/NGU/LCX units for the digital I/O which I never seemed to have any connectors for. This resulted in this breakout which could theoretically work for any DA-15 connection, but the silkscreening is especially helpful for those R&S instruments -

image

It is a trivial board to design. It was built with components sourced from element14 - the full project and gerbers are at https://goughlui.com/2022/10/02/project-da-15-d-sub-breakout-for-rs-ngx-lcx-digital-i-o/. A quick look at the BOM reinforces how the component cost makes the PCB cost literally insignificant.

The second addresses the annoyance of a lack of binding posts on modern test equipment. Sure, the shrouded banana serves a function in protecting users from high voltages - but if they aren't around, or aren't in use, then perhaps we should have a way to get away with connecting bare wires as that's often cheaper and more convenient.

image

That resulted in this four-way banana to 5.08mm terminal block break-out. Not a perfect design, but it does the job just fine for me - https://goughlui.com/2022/10/02/project-banana-to-terminal-block-breakout-or-where-are-my-binding-posts/. Once again, the parts costs dwarfs that of the PCB, but it does solve a real problem and makes my life quite a bit easier.

So, perhaps what I'm trying to say is ... PCBs are so cheap now, even with the international shipping, that perhaps we can stop obsessing about making things perfect and just send through designs for prototyping whenever it takes our fancy. It's literally "lunch money" but the result may well be more valuable in terms of hassle avoided or things learned. But perhaps the first thing one needs to learn is a bit of patience ... cheap shipping is almost always never going to be fast!

Hope this has been useful - you can build them, at your own risk. If you'd like a board, perhaps you can ask me although I would suspect the cost for me to ship it to you would outweigh the cost of just ordering them built and shipped to you directly!

Parents

  • I think I said something similar a few months ago.  When it’s that cheap, why pay extra for something like veroboard?  Makes prototyping and testing board layouts easy.  At one point, I designed a  PCB with different layouts for the same circuit so I could see if there was any operational difference in the two.  As you say, it can take a few weeks to arrive but the price outweighs thst (there’s always something else to be getting on with!)

    I created something similar to your breakout boards to connect my ICB up to a breadboard - 15DA to male and female headers.  I did put a 15DA connector as well mind because I had the parts and it allowed me to create cables that could serve multiple hook-up purposes.  It’s a great idea.

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  • I think I said something similar a few months ago.  When it’s that cheap, why pay extra for something like veroboard?  Makes prototyping and testing board layouts easy.  At one point, I designed a  PCB with different layouts for the same circuit so I could see if there was any operational difference in the two.  As you say, it can take a few weeks to arrive but the price outweighs thst (there’s always something else to be getting on with!)

    I created something similar to your breakout boards to connect my ICB up to a breadboard - 15DA to male and female headers.  I did put a 15DA connector as well mind because I had the parts and it allowed me to create cables that could serve multiple hook-up purposes.  It’s a great idea.

Children
  • in reply to Andrew J

    Yes ... I still have a few pieces of blank Vero ... and yet, I have little inclination to actually use them.

    Perhaps it's all those parts with non-100mil spacing ... or the hassle and the smell of it all. Somehow, I've been won-over by low-cost PCB manufacturing. Let's just hope that it doesn't go away anytime soon ...

    - Gough