PCB designs, Ethernet, and PoE

First off, I am working on adding Ethernet to my ESP32S3 designs. I am going for an KSZ8851SNL SPI Ethernet MAC+PHY, mainly because the ESP IDF has a module for this - so it should be a couple of lines of code (LOL).

I am also going for a Silvertel PoE module.

At this stage I have designed, and ordered, a board to allow me to prove the concept. It is somewhat more expensive than I hoped as I am using a large mag-jack, but I should be able to improved that. At this stage I want to prove it works, both Ethernet and PoE. I should have boards late next week.

But this has led me to thinking of a couple of changes to designs of some of my boards.

Faikout Remote

The Faikout is a small board you fit in a Daikin aircon. It works with Home Assistant, and that is how most people use it, but it also has a simple web control page via WiFi.

The Faikout Remote is designed for situations where this hi tech approach is not ideal, e.g. my guest room, and people without HA. It has a display and joystick button to show temperature, settings and allow control of the aircon via the Faikout. It actually connects to the Faikout over BLE, so can be used when no HA, or even without any WiFi.

Is is USB-C powered so easy to put on a wall with a simple USB lead. It has a temperature sensor, so can work as the temperature reference for Faikout auto mode, but can also work with small battery powered BLE temperature sensors if you want the reference elsewhere, e.g. by a bed.

The problem is I have gone overkill on this. The design also has a load of environmental monitoring sensors, including an expensive CO₂ sensor. This makes it unnecessarily expensive. So I plan to simplify things.

New Faikout Remote

The new Faikout Remote will have the display and joystick (though a more robust joystick), and temperature sensor (but also works with BLE sensors), and an IR receiver, but that is all.

The idea is it is cheaper and just works as a Faikout Remote. The IR is because you can use it with a Daikin IR remote (cover the actual IR receiver in the Daikin aircon).

This would be sold on shop.revk.uk with resin case and display. 

Env monitor board

Having removed all the environmental stuff from the Faikout Remote I would make a new Environment board. It would handle a display, but obviously this is optional as many cases do not need a display. It would include the sensors that were in the Faikout Remote...

• CO₂
• Humidity
• Temperature
• Pressure
• Noise
• Light (including colour)

The temperature uses a built in SHT40 temperature sensor (on thin long track with no ground plane, for some thermal isolation), temperature from SCD41, and from GZP6816D, but also WAGO for DS18B20, and, of course BLE sensors. The DS18B20 are commonly available as a probe on a lead, and one or more can be connected. This is ideal for things like data centre use, for front and back of rack, or home usage for inside and outside temperatures.

It would not have the joystick nor IR receiver.

Connectivity and power

This is where it gets more fun - the plan is Ethernet, so it can work on WiFi or Ethernet, and PoE so it can work on PoE or USB-C. The PoE would be a plug in module, so optional.

• Home use would typically be USB-C and WiFi
• Office use (and well cabled home use) would typically be PoE
• Data centre use would typically be Ethernet and USB-C, as data centres usually do not have WiFi nor PoE.

This should make it a very flexible environmental monitor, which is increasingly important for things like workplace monitoring for health and safety, as well as home monitoring.

This would be sold on shop.revk.uk with options for PoE, Display, and DS18B20 sensors.

I expect to get started on these soon, but obviously I really need to wait for my proof of concept first - that does not usually stop me :-)

Rendering

I have a simple task, it is auto generating some images for PCB designs.

This all worked, nicely. There are two parts

• Get KiCAD to render the 3D model of board, and make an image.
• Get OpenSCAD to render a view of my case design.

In both cases I want a transparent background, anti-aliasing, and cropped around the edges.

KiCAD

KiCAD has a command line that lets you make a nice image render, on a transparent background. However I was not easily able to control which layers show, and it showed stuff I did not want shown. This may have improved since. But also I wanted to change a user layer to an Edge Cut and remove the original Edge Cut to allow me to render a broken out version of the PCB. So I wrote a simple function to edit the KiCAD file before rendering.

I rendered larger and then auto-cropped in gimp.

In panel view

Cut out of panel

OpenSCAD

For the case designs, I have OpenSCAD make STL files ready to print, but I also wanted a render as a PNG. So I asked OpenSCAD to render the STL. STL has no colour so I picked white. But OpenSCAD does not render on to a transparent background.

I got around this by setting white/shades for the object and a very specific light blue background which is not in the object. OpenSCAD did not do anti-aliasing which makes if very easy - render larger - change the blue to transparent, and scale down for anti-aliasing.

I did all that in one imagemagick command. Worked well.

Upgrades

I have since upgraded KiCAD, and OpenSCAD, and gimp.

GIMP

GIMP is really good, and I do not want to dis it, honest. But gimp scripting is nightmare.

You would expect something like a simple auto-crop would be a simple command line. It is not. I had to make a script-fu script and put in the right directory (which was version specific). On upgrade I have to move it, but did not work. I have to tell the command line which interpreter to use now.

Even then, the script is a nightmare. I just want to auto-crop and images, so maybe three steps: load image, auto crop image, save image.

If you search you find examples (not for latest gimp) like this!

I managed to make a much smaller script, but still. One annoyance seems to be that there is no one simple place to find documentation of what commands exist and what arguments for scripts. Also, confusingly, some are plugin- and some are gimp-. I got it working but mostly by trusting examples I found not finding clear documentation.

When I upgraded, it did not work. This was difficult. Most commands had changed name, as had some arguments. I eventually got loading the file to work, and setting background colour, and even autocrop. But save file would not work. It seems a path and a string are not the same somehow, but my filename string worked for load, not for save, so inconsistent.

I gave up. I realised that I was doing this for the KiCAD PCB images as well, and in that case I used imagemagick.

In imagemagick it is magick filename -trim filename, so really simple, and worked.

KiCAD

The KiCAD update created something odd where it was showing the User.1 layer I used for V-Cuts, which it did not before. I had to change my tool to strip that layer. And now the images cropped correctly.

OpenSCAD and Background colour

But the OpenSCAD was bugging me - this was not a new issue as such, just I ignored it before. The PNG images seemed to have a black background. Noticeably when I look at a thumbnail on MacOS. This was not happening on the KiCAD based images.

I assumed it was the background setting in the PNG, and that was somewhat confirmed when I used pngcheck which reported the image was a 16-bit greyscale image with a background of 0x00FF. That is nearly black. I found no way to change this. imagemagick seemed to be setting only an 8 bit value for background on a 16 bit greyscale image.

In desperation I coded some C to update a PNG to set the background to a white level, got it all working, but nothing changed! My code was setting to 0x00FF. I tracked down, the image is 8 bit greyscale not 16, so 0x00FF is correct! pngcheck was misreporting as 16 bit (or was counting the 8 bits alpha as part of it, confusingly).

The fix, eventually, was to avoid greyscale as it clearly upset the thumbnails. I forced the original format which was 8 bit RGBA but simply prefixing the output file in imagemagick with PNG00:

This was a lot of yak shaving this morning.

Tindie

Their communications have been really bad - hiding that there was a take over, not explaining what was happening, blaming planned maintenance with no explanation why not simply rolled back, and then PayPal issues which they claimed were fixed, but clearly are not.

We are well over a month now with Tindie being broken - by which I mean this.

Not paying sellers is not paying sellers. This has to be the end of Tindie as a business, surely?

We threatened legal action and they settled the balance by bank transfer, phew, but we cannot start re-stocking products, even with over $1600 of "waitlist" orders, until Tindie are actually normally and routinely paying sellers. That may never happen now, we'll see. Even if they do get back, we may only list one product there for a long while.

We are far from alone.

Someone has even made a "new Tindie", from scratch, in this time. The site https://smallrun.net/ have managed it, with IOSS, and US tariffs, and all sorts, all working, from scratch, which even Tindie do not manage. This proves that Tindie's delays make zero sense. They could have re-made Tindie from scratch in this time - so why buy Tindie at all in the first place? Nothing about this makes any sense at all. i.e. make a new working platform, then buy Tindie brand and domain, and make a seamless change over - that is what you do, unless you are, well, incompetent. Well, IMHO, they are that.

An existing provider that was smaller, and has now grown a lot as a result of this, is https://lectronz.com/ - they are cheaper and bigger than smallrun, but I wish smallrun all the best.

This is where we have set up shop now - if you found us on Tindie, go to https://shop.revk.uk which I can ensure goes to my shop (Lectronz now).

But Tindie are still not communicating and not actually fixing things. It is a shame, they clearly had a reputation which is now in shatters.

CE

CE marking is important for ensuring consumers are buying things that are safe and meet their expectations.

However, CE marking has a lot of implications, in terms of costs and tests, and so on. It basically outlaws your average "cottage industry" type set up.

With modern tech, that "cottage industry" can be technological.

But what if it is not "safe". And this is a very good point.

So there are sites like Tindie, and Lectronz, that act as a platform / marketplace to sell loads of tech that is "home grown" and "cottage industry", with a lot of caveats on T&Cs.

My personal view is ...

• Most consumers need robust consumer protection law
• Buying something should, by default, be 100% safe
• If, and only if, the seller is super amazingly clear on what they sell should there be exceptions.

Oddly this ties in to the utter stupidity that is the fact England and Wales allow selling "raw milk". It is crazy, but the laws require (a) higher hygiene standards, and importantly (b) VERY CLEAR warnings that what you are buying is not safe to drink!

So are PCBs the same?

I make a load of PCBs, and sell a load. As it happens, as a company, we also make some serious routers. For those there is a SHIT LOAD of stuff we do to make totally sure it meets all the requirements. I mean, heck, this is stuff using mains voltage inputs, so it matters. And it costs a lot.

But we also make small PCBs, hobbyist stuff, prototype boards. And the cost of CE marking would be mental. Make 10 PCBs and pay £10,000 for testing and certification. No. That does not work, does it?

So can we sell them without a CE?

This gets in to a grey area, as CE mark is needed for most things but not, for example, prototypes. Indeed, you can order a PCB from China for your own use, and no way they CE mark / certify it for you.

And, after all, if one cannot sell without a CE, then the CE mark itself is pointless - if all sold products have to meet the CE marking requirements there is no need for a CE mark to say they meet it. That only makes sense if there can indeed be products not marked CE and hence declaring they do not necessarily meet the requirements, and so keeping consumers informed of that fact.

Interestingly, one of the key aspects of CE for many of my boards is RF compatibility, and for that the ESP32 module I use is CE marked and certified.

But we want to be 100% clear to customers that these board are not certificated or tested beyond that. They are prototype/dev boards, for specialist/hobbyist use only.

So we came up with a new mark... NONCE (Thanks Alex for help making that). Maybe we should trademark that, LOL.

And to be clear, what we sell is generally PCBs, in a panel, break off excess parts, and so on. And even if we sell a case it is a two part resin 3D print you use to contain the snapped out PCB. The end user does the "final assembly", it is a "kit".

At the end of the day we would not want to, in any way whatsoever, mislead a customer as to what they are buying, ever.

P.S. Apparently I need to explain we are not actually marking boards NONCE, that part is a joke!

Customising PCBs

It is pretty impressive what you can do with "silk screen" printing on PCBs these days. I think JLC even offer full colour now (not tried it). I imagine they have a UV printer.

But for some of my smaller run boards, doing an over print of the assembled PCB could be very useful.

I already have code to make 3D cases from PCB files - I can see me automating making an SVG overprint from the files.

Cheeky domains

I have a "shop" on Tindie (albeit currently all zero stock until they get working again, if ever) and now one on "Lectronz".

Ages ago I made tindie.uk domain, it web redirects to the shop on Tindie. Was a bit of fun. And a shortcut for me.

Now I have a Lectronz shop, so I made lectronz.uk in a similar way.

But this is a tad naughty maybe. Well maybe.

• As far as I know neither have a UK trademark so I could even make a legitimate business matching theirs, and even register a UK trademark, if I wanted, using their name.
• They could dispute with Nominet, but if I then did a UK trademark, I may manage to keep it.
• The URLs do actually go to their web sites (albeit my "shop" on their web site) so is not, in that respect, a breach of trademark - it references *them* - so just like someone selling Nike shoes can use the word Nike to do so, in an advert for their "shop". I'm selling/referencing their platform.

But yes, it is cheeky, shall we say. And in hindsight maybe a tad childish and not like me...

So now, given that Tindie is a waste of space compared to Lectronz, even when Tindie is working (which they have not been for a month), I now have a much simpler URL:

https://shop.revk.uk/

It goes to Lectronz.

FYI, if Tindie do come back I may list Faikout only, like we do on Amazon. Lectronz is likely to be the main place for any of the other circuit boards (and Faikout). Amazon only continue because they are one of the first places people go, still, so sensible to be on there, and they handle EU VAT, and shipping - but Lectronz do the EU VAT and US tariffs, so Amazon are only there to mop up on their reputation, as it is.

What is funny about Tindie is being off for a month is that someone has made a "new Tindie" from scratch and got on line and working during that month - https://smallrun.net/. To be fair, if I put my mind to it, I am sure I could. They even have tariffs and EU IOSS all sorted (which Tindie do not, still). How Tindie are so slow and so bad at communicating is really quite amazing.

&

The ampersand used to be consider the 27th letter of the latin alphabet...

i.e. ex, why, zed, "and - per say - and"... I.e. "and" was a letter after zed (Z).

Then came XML and HTML.

As a company with and ampersand in the official actual company name this has been, shall we say, challenging.

We had serious issues with BT XML order integration for some time.

But more lately.

Nominet say things like this...

    Registrar:

        Andrews & Arnold Limited [Tag = AAISP]

        URL: https://aa.net.uk

Yeah, that is NOT our company name.

Other examples, in that past, with bank payee verification showing ANDREWS ARNOLD LIMITED, so I created ANDREWS ARNOLD LIMITED registered (company 12972728) to complain that a different company was being shown than  us.

Now, for Nominet, I decided why not register ANDREWS & ARNOLD LIMITED. Then complain they are using a different company in whois...

To be honest I should have just renamed 12972728, but have done it now as separate company.

Firstly Companies House did not consider an 05555 phone number valid. Hmmm. But I did a different number, and applied for the company.

Now I get an email. An email to my x@x.xx format email address to tell me that my email address is invalid...

Yes, read that again. It is a kind of SPECIAL!

I called them, and well, the person I spoke to kind of appreciated the irony here. Emailing me to tell me my email is invalid, is, well, special.

She said the system was fine but a person, an examiner, rejected based on the email address. She has sent a memo to not reject that email. We'll see.

Why can people not simple follow standards, for email addresses, for phone numbers, for everything.

I have applied again. Once I have new company I can then complain to Nominet over whois.

And again rejected. Another weird one is when logging in to gov gateway using x@x.xx format address they say they are emailed a code to xx@x.xx !!! They actually email x@x.xx address, but why double the first letter when shown on screen... Hang on, I get the show first...last letter and a one letter address confuses the hell out of that. That makes more sense, but is still stupid.

Oh, there is more! The email from Companies house was wrong. It stripped & to &. Wow. How is this hard in this day and age?!