Looks like it.
Polyimide base material
And I see both coverlay (polyimide) and solderstop (traditional soldermask) options.
Solderstop would be easier, but it’s less durable in applications where there is going to be much flexing. Here though, you’re really just after the thinness of a flex pcb.
Right, after the redesign, the flexing won’t be needed anymore.
Are the other components (resistors, capacitors, etc.) going to be included in the manufactured pcb, or do I have to buy and solder those seperately? If that’s the case, then I’m missing a list of the parts required, or is it hidden somewhere in your github repository, @snowball ?
Unless your fab offers assembly and you order that (plus upload a parts list and pay for those), then no, it’s just the PCB.
Looks like the parts list is there
export_cart_20240417_041753.csv add LCSC part numbers
And the commit message for the schematic mentions the parts being added there too
adapter1.kicad_sch add LCSC part numbers
LCSC: https://www.lcsc.com in case they aren’t also manufacturer part numbers.
@ATi I have ordered the PCBs from JLC and parts from LCSC. It is usually hard to beat them on price. Shipping (also to Germany in my case) can sometimes be expensive but usually it is fine - if the package is small. I have paid 25€ for the PCBs including shipping and duties.
As the small parts are on the RP2040-tiny, I didn’t want to pay for PCBA. Also, I didn’t want to take the extra steps to make the design ready for PCBA. (Edit: PCBA means PCB Assembly, i.e. parts soldered for you. Sorry, too many abbreviations in engineering land and I sometimes forget which ones are obivous and which ones are not… 
)
The exported cart is what I have ordered (see @MJ1’s post, thanks 
). This is for multiple PCBs (always good to have a spare) and rounded up to MOQs. You can export a bill of materials from the schematic to see the actual numbers and you can omit some parts, e.g. only order the ATECC chip if you have a use for it. In addition, you will need the RP2040-tiny, Waveshare’s 3.7’’ ePaper and maybe the APDS-9960 gesture sensor breakout.
As you might have already noticed, I am not a hardware designer, but I’m willing to learn.
Although, I am going to need some help on the way.
The first time I saw the Touchpad Spacers, I immediately had the intention to replace them with a display module asaic. Until recently I’ve been busy getting my FL16 set up (Numpad was doa and got replaced, fp-reader connector got deattached and replaced, and recently the screen due to a bunch of stuck pixels), but now I’ finally ready 2 go.
My ideas for the touchpad spacer module include:
Do you hardware experts think this proposition is viable?
Please don’t hesitate to offer constructive criticism.
Regarding the implementation, I have a few questions, mostly for @snowball :
Searching for “PCB Gold Fingers” gives likely relevant results.
Yeah, fine. I don’t know what your skill level is for PCB and related topics. The PCB is probably the most frustrating part (and expensive if you need many attempts), so maybe make sure that you are good on the other parts before you start that: Soldering, firmware and software.
This should be an easy one to answer but I don’t remember 
I have removed several epapers from the PCB. It is a pain to do and it won’t succeed every time, so try and order it without the HAT if possible (or better: order both, so you will have a known-good hardware to compare to when debugging your hardware).
Hahaha, standardized connectors would be so useful… I couldn’t find any usable one on Ebay that had any information on the connector. I had to eyeball the pitch (and I got it wrong and had to fix it with some wires and tape). If you don’t need the touch screen, I suggest that you omit it unless you happen to find one that is thin enough and matches the dimensions really well.
Yes. The gesture sensor is just an additional gimmick (and I haven’t used it, yet).
The idea was to make this into a (very bad) security key but ATECC isn’t documented as well as I had hoped. We should rather upgrade to RP2350 if we want to do that.
I would say that it is mostly the same when hand soldering. You have additional design rules for the PCB (see JLCPCB’s documentation) and you have to keep in mind how the PCB will flex and how that will put stress on the parts and solder joints. I don’t know enough about that to get it good enough, so “handle the PCB carefully” is certainly part of the plan.
These are the parameters for JLCPCB (as the heading indicates), so have a look at their documentation. They know that semi-experienced designers are a large part of their customers and their documentation is often very useful.
https://jlcpcb.com/quote/pcbOrderFaq/Gold%20Fingers
No, sorry. Finding good parts can be a bit of black magic and that is especially true for connectors. Distributors have people to help you with that - if you will buy thousands of parts. Try different search terms, find online shops that might have the right parts and sell it to you, look through their inventory (sometimes for hours), learn which companies make relevant parts and how they name things, expect to spend some evenings on that if you have special requirements.
Hm, I don’t think that I have a good enough picture of what you want to do. I suggest that you order some of the parts and make a 3D printed mockup. I did that for my design and it was really helpful. This will tell you a lot more than just comparing numbers and drawings.
(If you don’t have a 3D printer, don’t order the parts online. Try and find a hackerspace/makerspace/fablab/… near you. You will need several iterations of the prototypes and it won’t be much fun if you have to wait for days in between and I find it hard to keep track of all the relevant information for so long.)
First of all, thanks for taking your time to answer my questions thoroughly. I really appreciate it.
I do have some experience with hand soldering and software, none with firmware and PCB, though. But for this project, you’ve done most of the work already. Practically, all I need to do PCB-wise, is to split off the connector part from your PCB-design and find a way to pressure-connect it to the rest of the PCB. That way, and by using the same hardware parts, I should be able to re-use your soft- and firmware, too.
That’s exactly the reason why I asked, as removing the display from the HAT looked troublesome to me due to imho no connection structures being visible in the pictures. Sadly, berrybase.de just sells it with the HAT attached. Did you order your display only version directly from waveshare.com or are there any other distributors you could recommend?
The Framework Laptop 16 does come with a fingerprint reader ready2use for such use cases. I do own a standard RP2040 Pico to attach to the HAT version, so I’d rather not switch to an RP2350 just for that reason.
Please take another look at my proposition. I’m actively trying to avoid using 3D printing and also stated the reasons. Cutting out the metal from the original toucpad spacers is going to be a real pain though, so I was hoping for some advice on that part.
Bascially, I’d like to split off the connector part of your PCB and glue it to the mid plate to ease the installation of the module. I also plan to modify a dedicated set of two official touchpad spacers for the frame of this module. Being no hardware designer, I can’t tell if this apporach is realistic, hence my question, if this proposition is viable.
The biggest issues with my proposition are imho the part of the touchpad spacer cutout resulting in the 5mm broad edges left and right due to the stress on the material on one hand, and soldering (or, if impossible, glueing) the two touchpad spacers together after the cutout on the other. Both of those steps are in dire need of advisory from metal experts and might require access to special machinery, so I guess many hobby designers try to avoid that hassle by using 3D printers.
It would be awesome, if some metal expert could comment on this, otherwise I’m going to have to look elsewhere for answers to those two issues.
Yes, but don’t expect anything like a finished product. I expect that you will want to add some features.
I probably ordered from Berrybase but Waveshare should be fine. Just expect the usual, i.e. EUSt and 6€ “Kapitalbereitstellungsgebühr”. I recommend that you get it without the HAT. It would be attached with some double-sided tape.
“Security key” like Yubikey/Nitrokey/… not a fingerprint reader.
Probably…? Give it a try. If the first plan doesn’t work, you might find a different one.
I would have access to some metal machines (including a CNC mill) but 3D printing has its own advantages. If you truly need metal for the strength, you can get 3D printed metal parts that are reasonably cheap (also from JLC). In any case, you can use a 3D printer for the mockup and later make the final parts with metal.
I think the spacers are anodized aluminium. Soldering anodized aluminium won’t work. We have soldered aluminium at the hackerspace but it needs special processes and isn’t easy (and many processes involve harmful chemicals). Welding is possible but also not so easy for aluminium. You can try glue but the geometrie might not be ideal. I don’t know which material is used for the non-metal parts of the spaces and whether it is possible to glue these parts.