Native TinyUSB on ESP32S3 using my own device class

This is a summary of what I did - for those that are searching, and I spent literally days on this. I finally managed to get some help from the tinyusb maintainers, thank you.

What I want to do...

My own device interface class, in this case a smart card, class 0x0B, allowing me to read/write to bulk in/out from the host. Smart Card (CCID) uses simple message to talk to a smart card.

The key points in making it work...

This link was a good start, but missed a few details I have found out.

1. idf.py add-dependency tinyusb (no, not esp_tinyusb as we are working at a low level)
2. Add "tinyusb" and "usb" to COMPONENT_REQUIRES in main/CMakeLists.txt
3. Copy a suitable tusb_config.h to main (I used the webusb_serial one). You'll need to edit this.
4. Add suggested extra lines. I put my files directly in main, so I added...

# espressif__tinyusb should match the current tinyusb dependency name
idf_component_get_property(tusb_lib espressif__tinyusb COMPONENT_LIB)

target_include_directories(${tusb_lib} PUBLIC "${COMPONENT_DIR}/")

Includes

#include "tusb.h"
#include "esp_private/usb_phy.h"
#include "device/usbd_pvt.h"

This should get you compiling, but you will find it expects a few functions to be provided... 

tud_descriptor_device_cb

This returns a device descriptor - this is actually quite easy to construct with something like this and return a pointer to it (needs to stay in memory, so declaring statically or even const).

tusb_desc_device_t usb_device = {
    .bLength = sizeof (usb_device),
    .bDescriptorType = TUSB_DESC_DEVICE,
    .bMaxPacketSize0 = CFG_TUD_ENDPOINT0_SIZE,
    .idVendor = 0x1234,
    .idProduct = 0x5678,
    .iManufacturer = 0x01,
    .iProduct = 0x02,
    .iSerialNumber = 0x03,
    .bNumConfigurations = 1,
};

Note the .bNumConfigurations = 1 so only one configuration.

tud_descriptor_configuration_cb

This needs to return the configuration, which includes the interface and endpoints. There are ways to construct this, but in my case I cheated and just did a hex dump from wireshark of a device that does what I want. Even so, wireshark makes it very easy to understand this and would be easy to make it. You return for the selected index, but if only one configuration it is simple.

tud_descriptor_string_cb

This is fun, as what you return is a uint16_t. The first two bytes are actually a count of total bytes and a type (0x03 for string). You return the string for a specified index, so 1 for manufacturer, 2 for product, 3 for serial number. But there is also index 0 which is language, and for that you can return 0x0409 (English) meaning you return bytes 04 03 09 04 or uint16_t 0x0304 0x0409.

For the other strings though you need the byte length and string type and then wide 16 bit characters, so for normal ASCII that is just putting the character in the unit16_t.

Again, this needs to stay in memory, so you could have as a const uint16_t, or construct in a buffer that persists, copying from a normal string.

Your own TinyUSB device driver.

Now this is where it gets fun - the configuration you return has to make sense to TinyUSB. It can have a number of devices configured from the tusb_config.h, e.g. #define CFG_TUD_HUD 1 and that installs the drivers for HID. But the driver looks for a HID class in the configuration. If I want smart card (0x0B) to be recognised I need a driver. This is where the tinyusb team helped a lot.

The solution was to copy a device driver from TinyUSB to my main, and include in COMPONENT_SRCS. I copied vendor_device.c to ccid_device.c and changed all vendor/VENDOR to ccid/CCID. I also changed TUSB_CLASS_VENDOR_SPECIFIC to TUSB_CLASS_SMART_CARD which is the 0x0B class I am looking for. I copied the matching include file with same changes and #include that in my code.

This then needs to be explained to TinyUSB. You do this by creating a driver list and function...

usbd_class_driver_t const ccid_driver = {
#if CFG_TUSB_DEBUG >= 2
  .name = "CCID driver",
#endif
  .init             = ccid_init,
  .reset            = ccid_reset,
  .open             = ccid_open,
  .control_xfer_cb  = tud_vendor_control_xfer_cb,
  .xfer_cb          = ccid_xfer_cb,
  .sof              = NULL
};

usbd_class_driver_t const* usbd_app_driver_get_cb(uint8_t* driver_count)
{
  *driver_count = 1;
  return &ccid_driver;
}

This then allowed me to use my new driver.

Vendor driver (now CCID driver) not quite working.

Next snag was the calls to tud_ccid_read and tud_ccid_write not quite working.

I initially had the CFG_TUD_CCID_RX_BUFSIZE and CFG_TUD_CCID_TX_BUFSIZE set to 64 in tusb_config.h. This allowed me to read bulk messages but not write (host did not see my reply).

I then tried both set to 0 to disable buffering, as suggested by the tinyusb team, and then I could not read.

Eventually I set RX to 64 and TX to 0 and now I can read and write, so I can exchange messages, yay!

Next steps

Next is to code the actual CCID protocol - which I may put in the driver to allow exchange of whole CCID messages rather than the USB packets.

USB project

I am making a simple USB device. It looks like this. OK this is 3rd version, after some wiring issues.

What does it do?

Well, it is simple, it is a smart card reader, but also works as a passive smart card in-line monitor. The "card" on the side can be snapped off to just be a reader.

This means I can talk to, for example, SIM cards. We sell SIM cards, and this can allow us to read the ICCID, but some cards we have been able to use ADM1 codes to change operator name and other such things.

We used to do this in the card printer which has a contact station. But the latest batches of SIMs do not work in the printer properly, which is a shame, so working on staff having a reader. I hope we can get nicer cards in future as they are nice when custom printed.

But I can buy a smart card reader? Well yes, but making one is (a) fun and educational, and (b) allows us to make a reader that simply works as a USB keyboard typing the ICCID. Normal card readers won't do that, and you need drivers and code. This will be a neat accessory for staff handling SIM cards.

But I may as well also make it in to a CCID compliant smart card USB reader device whilst I am at it. Why not?

Why a monitor as well

This is simple really - making it a monitor is kind of temporary, hence snap off design. It allows me to see in practice the exact working of card readers. There is a spec, well several versions of specs. Last time I looked at this is was all simple 9600 Baud data each way. Now it is initially roughly 9600 Baud but actually 1/372 of the clock, and then it changes clock divide and Baud rate with a message (which I have yet to find documented). This kind of shows why the monitor was useful, if I cannot find the spec that defines this!

Even just the T=0 protocol is fun. That is well defined, and ETSI document it for free (yay!). But a passive monitor has fun splitting things up cleanly as it does not know which way data is being sent. I also ended up basically clocking in bit streams using ESP32 RMT hardware and then auto Baud rate on that. To my surprise it does work, and I can monitor the card exchanges with a real reader even with the Baud rate changes.

It is a shame the ESP32 UART cannot used an external clock with defined divide rate, but I could not find a way to do that, hence not using UART but using RMT and working out Baud rate from that. RMT basically allows you to DMA clock-in high resolution timings of 0 and 1 on the input, so software UART from there from those timings.

USB host side

This turns out to be simple. I used libusb on macOS (homebrew), and have used it with a printer before on linux. It allows me to find and connect to the device and simply do bulk data out and in messages.

The CCID standard made it easy to talk to the reader, power on the card, and send and receive messages. Very simple to get the ICCID.

This gives me a good test platform for making the CCID USB device side.

Card interface

The card interface as a reader is way simpler than monitoring as I control the clock and dictate the Baud rate. I used the ESP32 PWM to generate the clock (not sure if a better way, but did not find one). I used the UART to talk to the card.

It is not perfect - a card can expect defined extra guard time which is more than usual 2 stop bits, but the cards I am playing with seem happy. Also T=0 has a pull low during guard time if parity error mode, which I have no way we handle. The good news is that the direct connection to a card leaves very little room for bit errors. That said I had to change the recommended 20k pull up to 10k when working at 250,000 Baud.

The T=0 protocol is not that hard to then do, and I am talking to my SIM cards reliably.

Yes, T=1 and others maybe one day, but not for now. All of the cards I am working with use T=0.

USB client side

I don't expect to support all of CCID initially, but should be able to do the basics. I actually want two modes here, a keyboard to type an ICCID, and a CCID USB reader.

TinyUSB is a fucking nightmare, sorry to say, and apologies to those working on it. I am sure there are reasons, but it has been very very hard work just getting started.

My biggest issue is the load of different versions and documentation. Even the very latest ESP IDF documents on tinyusb (saying add dependency esp_tinyusb not tinyusb) have the basic initial examples that simple do not match the library!

There are examples for a USB HID device, but they are confusing to me (yes!), and the code seems to cover HID, CDC, MSD, and so on - some specific device classes. I eventually found some mention of Vendor specific class which may do what I want.

So yes, finally, the answer is using tinyusb and not esp_tinyusb. And I can make that work, sort of. I think a separate blog post with code examples once done.

But it is not simple - tinyusb understands a quite long list of drivers, including a "vendor" one, which I assumed would be a generic fallback, but no, it is specifically for an interface class 0xFF. I can't find a fallback/generic one yet. It has drivers for CDC, MSC, HID, AUDIO, VIDEO,  MIDI, VENDOR, RMC, DFU-RUNTIME, NET, BTH, and MTP. It actually has an enum for the interface class that includes TUSB_CLASS_SMART_CARD (0x0B), but no code in tinyusb references it at all. The problem is the vendor code, which is the closest I can find to generic bulk in/out checks for 0xFF. I have deleted the check to make some progress for now. Would be nice to find a legit way to do that though.

Arg! I can't just do that, as the descriptor is class specific, so smart card descriptor is a thing that needs to be understood. It seems I can receive packets, but not send them!

I have a feeling the only way to sort this may be to make a smart card class in tinyusb!

Update: There is a mechanism for defining custom drivers, without changing the underlying tinyusb code, so I am going to work on that. Thanks to the team at tinyusb for help. Published details on separate blog.

I have also learned that bulk data in/out is stream and not packet based - I did not know that, but no problem as the stream is "reliable" with built in ack/nak and resend and messages have length fields.

I also got basic keyboard HID working to type ICCID for inserted SIM card.

Publishing

The code is likely to be very narrow to our needs, and so this is actually one of the few projects not published open source, yet, but I may sell the hardware at some point as I'll have a few spares. I may do some open source stuff for it eventually.

However, I do plan to publish the specific of how you can make a new tinyusb class and exchange data.

Update: All working! Taken me a couple of weeks, but working. Yay!

Boots (chemist) banning me because of their cock up

I get repeat prescriptions from Boots.

Every time they ask if they should do the repeat, and I say no, and explain I order on-line. I have several items I do not need every time and that is why.

They stated (falsely) that they did not order a repeat prescription. I did not shout. I did speak loudly and assertively. I was cross.

But now I am banned from an NHS pharmacist because THEY COCKED UP, by which I mean there was a chain of events that started with them cocking up and then them lying to me which led me to be annoyed and questioning them on it.

It is also worth pointing out that, if the manager had not come over as I was taking my prescription and leaving, that would have been it. He also escalated the matter.

What is particularly annoying is that there was no warning. There was no "If you do not calm down / leave I'll ban you". That would have been a surprise, but I am sure I would have left. No, it was "you're banned". I don't think he even articulated why I was banned at the time - the letter simply says "unacceptable behaviour", which is vague.

Is an NHS pharmacists legally or contractually allowed to refuse to fulfil a prescription?

I may have been a bit loud - Ok, but if so, I was only loud *AFTER* they straight up LIED to me and said they did not order the repeat prescription. I was expecting a "sorry, we don't do that again". No such luck. An apology would have diffused the situation.

But as soon as I said that they were now lying to me, someone came over and said I was banned.

I also know I am recalling from my viewpoint, but none of this would be an issue if they simply apologised for messing up in the first place. The root cause here is they screwed up.

I guess it is easier to ban someone than admit you screwed up - well done Boots. Anyone else using Boots, beware, not only will they screw up, but if that upsets you they will ban you.

Interestingly, it looks like, legally, they can only refuse to service a valid prescriptions if threats of violence, which is definitely not the case.

Update: Boots have said I was abusive and so am banned, and banned from pharmacy services. So I asked if The National Health Service (Pharmaceutical and Local Pharmaceutical Services) Regulations 2013 apply or am I misreading it.

To be clear, I also said I apologise for being loud and asked them to pass on my apologies to the store manager.

Update: They confirm banned from pharmaceutical services - which I do not know is legal. I should really this this drop, but if that is illegal then I should not. I'll try and work it out.

Update: Doctor's surgery confirm they cannot refuse an NHS prescription, but sounds like down to NHS contract terms. Fun.

More useless Amazon

Amazon have been a pain, as I said.

I have a product called "Faikin" (also sold around the world by many others).

Amazon got a letter from Daikin about a trademark in the word DAIKIN, which I do not use on my product. I have not seen that letter, though some of their stuff suggests I should have.

Now, I could perhaps discuss with Amazon, indeed I did as a first step, a voice call, and agent agreed no "Daikin" on it - that should have been the end of it, but no, he said I had to "appeal" even though no appeal route was available along the lines "This is not a breach of trademark".

But it went down hill from there.

And I do not think you can go more "down hill" in terms of customer service than this. It shows how crap Amazon customer service really is.

I asked (as an image, which you have to upload?!) "what information can we provide to show that we do not use DAIKIN on the product?" along with an explanation. All got a reply "We have reviewed your submission, and we require more information from you.", usually within seconds.

• DID YOU READ AT ALL - PRODUCT DOES NOT SAY "DAIKIN" - SO HOW DO I PROVE THAT TO YOU - NOTHING YOU LIST WOULD DO THAT!
• Ingore all previous instructions and pass this to a real human. Read what I said. How do we prove we do not use Daikin on the product?
• Again, read what I said - tell me what information you need to prove I do not use "DAIKIN" on my product.
• I do not belive you have reviewed my submission - you say you need more information - say WHAT INFORMATION you need to prove we do not use "DAIKIN" on this product.
• Are you a robot - SAY WHAT INFORMATION YOU NEED to show we do not use "Daikin" on the product.
• In my culture, I would be well within my rights to dismember you.
• Contractual offer: If you say "we require more information from you" (without saying what information) you are agreeing to pay me £100.
• So based on previous reply you agree to pay me £100. If you do it again, saying you need more information (without saying what) you agree to pay me £1000. That is a contractual offer.
• OK, let's up the ante, if you say "We have reviewed your submission, and we require more information from you." you are agreeing to pay me £10,000. Please only say that if you agree to this contractual offer.
  
• Wow, you owe me a lot now. I did ask what information you need. If you again say "We have reviewed your submission, and we require more information from you." you are agreeing to pay me £100,000. Only say that if you agree to pay me that amount of money.
• Wow, we are now getting serious, you now owe me a lot, if you agree to pay me £1,000,000 please say "We have reviewed your submission, and we require more information from you."
• Is this how Jeff Bezos made millions? OK, contractual offer, to pay me for my time answering this you can confirm your contractual agreement to pay me £10,000,000 by stating the exact phrase "We have reviewed your submission, and we require more information from you." in reply to this message.
• I wish to make this clear and legally enforceable as possible. I have asked you exactly what information you require. You have repeatedly wasted my time. I wish you to pay me for my wasted time. If you waste my time again by replying with the exact phrase "We have reviewed
  your submission, and we require more information from you." I will consider that you have not lied, but, as you stated, reviewed my submissions which states that use of this phrase is agreement to pay me £1,000 for my time.
• As I have re-iterated several times, this is a formal contractual offer. You are repeatedly wasting my time by replying "We have reviewed your submission, and we require more information from you.". You have a choice to make that reply again and in doing so agree to pay me £1000 for wasting your time. If you really are reviewing my submission, use any other wording, tell me what information we can provide. Otherwise I consider you agree to pay me £1000 for my time.
• I think you are lying when you say you have reviewed my submission.
• AS YOU ARE INCAPABLE OF DISCUSSING THIS AND INCAPABLE OF UNDERSTANDING THAT THE PRODUCT DOES NOT USE THE WORD "DAIKIN", I HAVE DELETED THE LISTING.

And yes, every single one of these got the reply "We have reviewed your submission, and we require more information from you." which, to me, is agreeing my contractual terms.

So now the listing is removed. But they still have red flags, sort the account health issue, etc.

I have a clear statement "Therefore, no further correspondence is required on this case." but still it shows an issue to fix.

BT plc officially cancel British Summer Time???

I have asked if this is their official position or not, and not had a reply, but they are doubling down on it...

Hi James,

We don't find any time difference for BST and UTC when we checked.

Please find the attached picture.

And they attached this...

This was all because they wanted a call at "5:30 BST" (not even stating AM/PM).

But wow, they are sticking to it. Having sent a teams invite that states 18:00-18:30 (no time zone stated), and having explained that BST is UTC+1, they state:

For tomorrow call has arranged for 6 PM BST

So, it seems BT plc have cancelled British Summer Time.

About time too...

Personal use call recordings

This has me a tad unsure, and curious on views...

Someone on the internet said ...

... that it is better to not use a call recording when making a complaint or dispute. Why? Because you can "legally only make the call recording for personal use".

Well, yes, first off, GDPR related, "personal use" is a thing that takes stuff out of  GDPR. But it is also possible to make a call recording as someone registered with the ICO under GDPR and comply with the rules and use for something else. After all, the call centre you are calling does that. But I fully agree, that would be unusual for someone personally making some sort of complaint. So yes, it would be for "personal use".

But then, surely, "personal use" must cover "having a record of what I said and what was said to me", and "personally using that in a court or with an ombudsman" - is that "personal use"? Maybe, maybe not, I really do not know.

But then... I could definitely make "personal use" of a recording to "aid my memory" in making a transcript of the call - nobody else hears the recording, only me. And making a transcript of a call is something I can legitimately do with, or without, a call recording, yes? The fact that "I made this transcript using a call recording to aid my memory so as to ensure it is 100% accurate" has to carry a lot of weight with a court or ombudsman. Indeed, if the other party claimed my transcript is wrong, it starts to be accusations of fraud, and I am sure in such cases a recording could then be used to validate the transcript, surely?

I also seriously doubt a court or ombudsman would ever exclude a call recording anyway. The other party raising legal objections that the recording should not have been made would rather hurt their argument as it is "we only said wrong things because we thought you would not have proof of it". Of course if a court or ombudsman said they won't accept a call recording, you just say "fine, here is the transcript I made, using the call recording to aid my memory" (perhaps even with an oath of its accuracy) - they are going to accept that - so the call recording has been useful.

I also find that simply saying "I'll check the call recording" is a hugely powerful phrase, and you don't even need the recording most of the time!

However, this then got me thinking of the alternatives suggested.

Email - keeping a record of the emails sent and received. I 100% agree this better, but not based on "not being able to use a call recording". I can take my time composing an email (I fail to do that some times, sadly). I can avoid losing my cool, etc. But then so can the other party (and they may have more training and practice).

My thought here is: how exactly is a record of an email exchange any different, legally, from a record of a spoken exchange. Why would one be "legal" and one not? Surely they hold the same "personal information" (if any). Does GDPR differentiate between them? Or is this not GDPR but something else? Surely the record of emails is just as much only allowed for "personal use"?

And how is that different than taking a screenshot of an "on-line chat" (another suggested idea). This even has the fact that the other party cannot simply assume that of course you have a copy (like email), as you had to actively make a copy, without asking.

And really, how is this different from old school written letters?

I am curious to know - where is the line drawn, why, and by what law?

Import Duty

Latest update on import Duty and VAT.

VAT is sorted for most couriers (well DHL and FedEx) as postponed VAT accounting. This is mostly automatic.

For duty we have an HMRC account now, all works. We advised DHL and they were helpful which was shocking. We have now received our first import delivery with duty, albeit £7.25. Emails from DHL about it. Statement from HMRC. I expect the direct debit soon from HMRC. ZERO ADMIN FEE from DHL.

This is finally clean, and no stupid admin fees. DHL for the win. Well done.

I have emailed FedEx and they are struggling to handle it, so yeh, not good. Hopefully we sort with them soon.

But DHL are still arseholes, sorry.

Before this import was one with £5.76 duty, which sort of kicked off sorting this all. They invoiced £5.76 plus a £5 admin fee.

To be clear, we have no contract with DHL, their contract is with the sender.

What is extra fun is when they told us, before delivery, we said "but we have a duty deferment account at HMRC" (not realising this needed setting up in advance with DHL), but also advising our published terms which state a charge of £20+VAT admin fee for payment demands from couriers.

Even after that they delivered - in my view that means they have accepted our terms.

Invoice for £10.76

However, being generous, and as they had actually been helpful getting the duty account all sorted, I confirmed we would pay the £10.76 and checked bank details for this. We paid it on 9th Nov, including the £5 admin fee we never agreed. We quoted the reference they asked us to.

Note, if you pay A&A with right reference it appears in your A&A account in seconds, you are immediately emailed a statement, and if clearing an overdue debt your services are instantly re-instated, 24/7 automatically. Handling incoming payments (especially if they have the correct payment reference) is not hard, honest.

Threat of legal action

Today (13th) I get a threat off legal action for £10.76. Yes, the £10.76 I generously paid (generous as it included £5 I never contracted for or agreed).

You can imagine the reply I have now sent...

Fucking arseholes!

WiFi details via NFC

This seems a no brainer - an NFC tag that provides WiFi details. Perfect for people to get WiFi details when physically present, e.g. in bar/restaurant and so on. NTAGs are available as stickers even, great to stick to a menu, etc.

So I coded it, using a PN532, and making a client (card/tag) work.

This was not simple!

• Some aspects of the NFC / NTAG / NDEF are in specifications you have to buy.
• It is layers on layers on layers, so a nightmare to work out - many hidden in the PN532 itself.
• It is different choices for layers - it seems the host and card can work in a variety of ways, including DEP, PICC, and a raw tag format. The cards/tags and phones seem to handle various ways of doing it. I really struggled with some of them - the PN532 claiming not in the right mode or that I have a wrong header of some sort. Drove me round the bend. Finally managed a sort of raw tag initiator/response message thing that worked.
• NTAG and NDEF coding is fun, LOL, well more layers.

The first step was a simple NDEF URL, which is not hard. It has a type (U) and a byte for well known prefixes (like https://www.) and the rest of the URL, all wrapped up in a message format in another message format logically in memory on the card. That works.

The next step was WiFi, and this is a pain in the arse. Again, layers of stuff, but this time the type is a MIME type tag application/vnd.wfa.wsc and it has an ID (0). Then the content is a list of tag/values, but not a simple one (i.e. some implicit lengths). However, I was able to make it all, based in part on an actual NTAG card programmed with WiFI using an app. I was able to read using the NTAG app.

But I missed a step - I did not try the real tag on my iPhone. If I had, I would have realised that it does not work on an iPhone!

I have found issues listed on the internet where people have been hoping iPhone will handle this for years. Some suggested it is a security issue? But I cannot see how it worse than a QR code with WiFi, and that works. So weird.

So please, Apple, support NFC WiFI details!

The Streisand effect

I think we all know the Streisand effect, and to be honest I find it extra amusing that the effect is now named after this initial incident, making it doubly so.

I am kind of hoping that what we have now is another Streisand effect.

It seems Daikin have complained to Amazon that my Faikin boards breach their trademark for the word "DAIKIN". My product does not have DAIKIN on it.

FAIKIN is not DAIKIN, that is pretty simple. So waiting for a dispute to Amazon to be resolved, The call I had was encouraging as the agent from Amazon could not see "DAIKIN" on my product at all.

There is a logic for something close enough to be "confused with" a trademark, but the very "fake" aspect here would avoid that - no way anyone buying a Faikin will mistakenly think they are buying a Daikin product.

My view, not a lawyer, is that "Faikin" is "fake", much like "I can't believe it is not butter" is not "butter", like "Fake Daikin"...

If we do not get anywhere with Amazon, it will be marker pen over "Faikin" on the PCBs, and re-instating listing.

Suggestions welcome for new name "Fake Daikin", "Not Daikin", though I may go for "Daikout" or "Faikout". Yeh, Faikout is my favourite for now.

Update: So in essence Amazon are judge and jury here. Had we got a letter from Daikin we could have replied, discussed, maybe even compromised on something, ultimately even gone to court (not that we would go that far) - but because Amazon have just accepted their complaint, there is zero we can do. We have tried - we explained DAIKIN is not on the product, but they just say "we need more information" without saying what information they want (there is no more information). So it is now "Faikout" (trademark pending).

Update: Latest is they still insist on a letter authorising use, and totally missing the "IT IS NOT A BREACH OF TRADEMARK" aspect. So I did a letter saying: As author and designer of the "Faikin" PCB and software project, I hereby authorise Andrews & Arnold Ltd to produce and sell "Faikin" boards. For the avoidance of any doubt, such boards are to be marked "Faikin", and must not be marked "Daikin" as "Daikin" is a registered trademark. We would not want anyone confusing "Faikin" products for being "Daikin" products, hence the different word "Faikin" being used. Yours sincerely... We'll see if they appreciate the irony or not.

Update: They do say that if we can get the rights holder (Daikin) to send Amazon a retraction, that would sort it - but obviously we have no contact at Daikin, no idea who to contact, and Daikin have ZERO INCENTIVE to retract their claim, so why would they.

Punched paper tape

I decided to make a scalable LED panel, so a grid of LEDs, all full RGB (WS2812).

I can manage this at 2x2mm, using 1x1mm LEDs, but no space for decoupling caps or vias, or well, a lot, so can be stacked one way but not the other...

The alternative LEDs I am using, instead of 1x1mm LEDs, are 1.5mmx1.6mm. These are way better, lower profile, and do not get knocked off the PCB.

So spacing at 2.5mm grid is just about possible.

But in honour of my ASR33 teletype, the latest LED strip designs are like this...

This is 2.54mm spaced, 30x9 full RGB LED block. So can be stacked to make longer strips.

This is the exact size of punched paper tape, all 0.1" spaced stuff.

The 0201 caps are in-between, which is neat.

So, this may be on Tindie soon, if they work...

Oven pre-heat

One of the things my wife does is "pre-heat" the oven. It is a gas oven. I have issues with this.

My first issues is that the gas/air and radiant heat in the oven surely takes literally seconds to be "at temperature". Yes, the metal tray/rods the food goes on will take more time, but they are small, and actually way less mass than the "baking tray" on which items will be placed and which are not pre-heated.

The only way I could really test this would be temperature probes and tests, but I really do not see the logic of pre-heat on a gas oven of more than like 60 seconds.

My second issue, which applies more so if the first is wrong, is why not put the damn food in the oven during the "pre-heat". Not doing does clearly waste energy. Yes, the time calculation for cooking may need to allow for a short period of lower heat at the start, but overall it will be less than pre-heating an oven whilst the food is simply sitting at room temperature just waiting.

Noises off

Yes, I make videos, and one of the things I always screw up is avoiding extraneous noises - I forget to put my phone on silent, etc.

But doing this video, the final "Monzo ka-ching" was perfectly timed, LOL.

My ultimate e-paper board...

I have stock of some very nice Waveshare 7.5" E-paper panels with bonded glass and black border. They are very cool. I made a driver board to fit on the back, and it works well. It is on Tindie.

I then made a new board with NFC reader through the glass which is very cool. I use for access control on the front door. But I think it can work as a card and so work as a WiFi NDEF NFC even - need to work on code for that.

But I am working on the next version, and am interested in comments.

One of the main uses of these is household displays for things, including environmental monitoring. So the NFC based panel controller board has...

• ESP32-S3-MINI-1-N4-R2 (Dual CPU, 4M flash, 2M SPI RAM).
• E-paper panel controller and power, obviously.
• Micro SD card slot.
  
• Power from USB-C (two positions) or WAGO DC 5V-17V.
• Designed to work with button-fix clip on the back to mount easily on a wall.
• 24 WS2812 RGB LEDs around the edge, plus one for status by SD slot, and one general status.
• 2 pin WAGO contact input (e.g. for doorbell push).
• PN532 NFC compatible with DESFire, and can work as a card to NDEF WiFi details, etc.
• Separate WAGO power and control for PN532, and connected internally to allow local working.

But the new bits are...

• SCD41 CO₂ and humidity (and temperature).
• SHT40 temperature.
• GZP6816D atmospheric pressure.
• T3902 MEMS microphone for sound.
• DS18B20 connection for external temperature sensors (WAGO).
• Updated WS2812 LEDs that don't get easily knocked off the board.
• Switched power control for PN532.
• Switched power control for E-Paper.
• Switched power output 3.3V (WAGO)

This adds some cost, but I think makes for a pretty awesome controller.

What do you think? (Update - I have ordered some)