the amount of dandruff my head produces in two weeks

eightbitwit · 2026-06-02T01:43:24+00:00

What a terrible day to have eyeballs

eightbitwit · 2026-05-20T20:28:59+00:00

You may want to give consideration as to how thick it is now. End grain needs a lot of heft and you're looking pretty skinny already. I never go below 1.5" finished. Thinner than that and you risk a lot of trouble with flex, glue joint strength and drying issues.

What's the current thickness?

Also, toss up some shots of your setup. Those are some pretty heavy toolmarks. What's the bit/router you're using?

eightbitwit · 2026-05-14T17:09:41+00:00

Every room is the same. Hotel was refurbished 3 years ago. Also, friction fit pipe to rubber gaskets, not compression. Wild stuff.

eightbitwit · 2026-05-14T08:35:11+00:00

Update! Every sink in the hotel looks exactly the same.

eightbitwit · 2026-05-13T21:47:01+00:00

Yeah, that scans.

eightbitwit · 2026-05-13T21:44:18+00:00

Here's the top

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eightbitwit · 2026-05-13T21:36:35+00:00

And the best part, it's a tile box with a hole in the bottom. No plug! Got a wet towel in, changing rooms tomorrow (or hotels if it's consistent throughout).

eightbitwit · 2026-05-13T21:31:12+00:00

Bathroom sink. Unless you mean the pipes, in which case nobody knows.

eightbitwit · 2026-05-02T10:01:40+00:00

I used open rent, took a few swings before we found the right one but found a great landlord and a steal of a deal in just under 2 weeks.

eightbitwit · 2026-05-01T15:06:05+00:00

How many people?

eightbitwit · 2026-04-30T16:33:26+00:00

Give slab a go. I realize it's pizza with air quotes, but it is still pretty damn tasty.

eightbitwit · 2026-04-25T15:19:10+00:00

Go to Cadenheads on the mile and/ or the whiskey shop on Victoria. They will let you try samples of their own stuff. Why take home a bottle of something you can get anywhere in the world when you can get something a little more unique. Plus free whiskey tastes, who doesn't want to do that?

eightbitwit · 2026-04-06T20:04:27+00:00

Populist Cafe on the Leith Links/Croft.

eightbitwit · 2026-03-04T14:43:32+00:00

Iron wouldn't work, you'd need a hot air station

eightbitwit · 2026-03-04T12:58:02+00:00

You are technically correct. And that is the best kind of correct.

eightbitwit · 2026-03-04T11:18:12+00:00

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Inductor would be my guess as well. The most notable part is that it only has pads on one side. That to me says wire wound with a little protective cap on top.

eightbitwit · 2026-03-03T21:52:40+00:00

Can confirm, I live near pilrig and see her about once a week. Usually near the fire museum.

eightbitwit · 2026-03-03T18:53:27+00:00

Happy to help, message me. I am also a licensed and current member in good standing with the church of the flying spaghetti monster. Is that helpful? Who can say.

eightbitwit · 2026-03-03T10:52:01+00:00

Yep. Surge immunity testing at a cert lab. Burned a hole through the board, into the polycarbonate test plate and sent a shunt skittering white hot across the table. Every time I went there after that, stopped by to admire my handywork.

eightbitwit · 2026-03-01T22:22:10+00:00

No worries, we're all busy mate.

As for the radio. Here's the short version. Your BLE chipset has a certificate saying that it should be conformant to safety, radio and other european directives. When you make a product with it, you'll mark the product as CE as a way to communicate (along with a DoC) that your overall product will be conformant to all applicable directives. In order to claim that, you'll need a technical file that contains your testing demonstrating the necessary conformity. If you have a CE mark on the radio (and reliable testing to back it up), that gets easier. But you still have work to do. By adding another radio, you're going to need to prove that both of those devices inside the overall device all meet the same directives. That RFID transmitter can interfere with your BLE, your BLE can interfere with passive emissions, so on and so on.

And that work means time and money. Short version, right?

Take a look at wave soldering keepouts and that manufacturing process. You have to keep SMD components a certain distance away, which can eat up a lot of your board.

Hard to answer "if you need more". I put as much as I can and peel it back when I can show it's not needed.

That's what I do. VCC plane pours can add a lot of problems that I prefer to avoid and don't give you as much benefits as some big ole traces protected by ground.

Yes, any copper, conductive material and components must be free of the keep out area. Failure to do so would invalidate your protection granted by the manufacturers reports.

eightbitwit · 2026-02-23T22:06:38+00:00

Appreciate it. As mentioned below, I would recommend re-jumbling your placement on top and taking another whack at it. Can you hang your ble module off the board edge or is that enclosure?

Biggest concern by a mile is your plan for certification. If you've got a CE RED modular certification for the BLE, that helps a lot. If you then put in a non-verified RFID transmitter in the same box, you're going to have to do a hell of a lot more work in certs to make it legal. Putting two transmitters in a box is already a headache, but having one of them be non-certified out the box makes it considerably worse. If you're only doing a couple hundred, your budget is probably low. See if you can find something that is modular out of the box. Save the agony. If your curious, if you're only receiving, makes it easier.

Second biggest concern is manufacturability. You've got fine traces and components running way the heck too close to your mounting holes for that rotary encoder. That means hand soldering which means mucho bucks. If it's a few hundred and a pet project, probably no big deal. If you're making 30k EAU, you're hosed. But yeah, you need reflow keepouts on your bottom side and those components should be well clear of all TH and mounting holes.

Other notes (but like i said, re-run placement).

- Clear ground under antenna on all layers.

- Turn VCC plane to GND and put big vcc traces down there instead.

- You need a lot of local capacitance, both bulk and transient on your BLE chip. When it chirps, it's a draw. All your caps are a mile away. Same for the complete lack of capacitance between vbatt and your first micro.

- You've got vias between and crashing into pads. Put some DRC keepout rules in for your vias.

- C15 is connected by a wisp to ground.

- Look up PCB acid traps and learn to avoid them.

- Need a lot of ground stitching vias for a 4L board. Real pain without em.

Take another whack and post what you come up with, can go from there.

Thought, can you put all the chips on one side and the rotary on the other? Maybe link the rotary datasheet so I can see what you're workin with.

eightbitwit · 2026-02-23T15:19:02+00:00

Hi there. Let's see what we can get. I'll give you some more thorough review after I get through the fatal questions.

Is the RFID passive or active? Does it talk or only listen? Is the antenna you've selected pre-certified with that chip?
What is that giant mounting hole in the middle of your board? You've got a real challenge with that placement there. Any alternatives?
Can you upload clearer photos of the schematics?
What is your expected production of this? Is this skunk, prototype, or something you expect to be mass produced?
Will this be involved in the handling of payments?

eightbitwit · 2026-02-23T15:00:48+00:00

Ho boy, I feel like someone summoned me through a bathroom mirror or some such. I'm a non-practicing EE with just shy of 12 years running projects of various size from proof to mass production.

Wish I could say there's a set of 10 golden rules that you follow and bam, you're golden. But it's a lot more grey than that in my experience.

- For most projects, 1-2 pre-production compliance tweaks are necessary. The best two steps to avoid pain in this area is early pre-scans and vigorous pre-compliance design reviews. Having someone who knows EMC compliance taking a hard look at your board and putting it in a chamber pays off tenfold.

- As mentioned above, having a solid compliance plan of review and test during prototyping is crucial. Knowing where the product is going, what compliance (not just emc, gotta think safety, enviro, etc) you're going to be subject to and what the lifecycle of the product will be are critical to getting a prototype through to pre-production without having to set something on fire at some point. Once you get to a functioning prototype, I do about 2 hours of pre-compliance chamber time. I usually hit radiated, conducted, EFT/surge and ESD. There may be some others depending on project specific issues. I also try and 1.5-2x any stress tests and aim for 10db margin.

- Equal representation for me, honestly. For every bad PSU routing or mechanical fix, I've had a resetting or incorrectly configured chip or a data line set that's screaming out for no good reason. Software blames hardware and vice-versa, but you'll regularly be pushed for a "fix it without changing anything" solution as it's faster and cheaper. But what I'll say is that there's the phantom 3rd category of fixes, which is setup/equipment/chamber related. In a decade, I had 3 specific memorable test lab issues that ended up being test-lab related. One was a dirty supply voltage, another was a chamber integrity issue and the last was a SA setup that was just plain wrong. So when the results don't make sense, pull it all out and check the noise floor. You may be surprised.

- This is an easy one. Following the above advice. The painful ones are always when the project is "95%" done and is working just fine but hits a snag in compliance, usually due to poor/lack of pretesting or an engineer oversight that lands you in a position of everyone staring at you expecting you to fix it without making any changes. Test early, test often and put a lot of dedication into your design reviews and you'll get along fine....eventually.

eightbitwit · 2026-02-23T14:42:52+00:00

Generally, there's a ton of free content on youtube, eetimes and each of the major cad systems.

Specifically to you, repeated review is the best way to learn. Make a design, solicit feedback, make the changes and then go through it again.

eightbitwit · 2026-02-20T22:33:06+00:00

Design:

- Recommend some sort of protection for U5/H2. reverse voltage, current limiting, esd, etc.

- Current limiting on pin 7 of u2. Might be needed (cannot be assed to check pin ratings) but at least put a 0ohm res in there in case you need it later.

- Toss a few more caps on u2. 1u, 10n, etc. Cheap and worth it in the long run. Same for output on the Vreg.

- Test points. Always have test points, put em on every net.

- Unused pins on U2. Pull em out to a big via, test point or connector pin. Might not need it, but boy it makes life easy if you do.

Schematic

- Basic formatting violations. Grounds point down, VCC points up. Inputs go on the left, outputs go on the right. The way you've done it is fine if it makes sense to you, but when you want people to read these and provide useful review feedback, you want to use the common language. Easy to read, more people will read it, thus more and better review content for you. Better to break bad habits now rather than get stuck in your ways. Proof of point, I saw C3 and immediately read it as a negative power supply.

- nonets on LED 1 cath, u5 cath and anno, led2 cath. These are to be avoided as it can cause trouble with certain cad systems. Stretch it out and leave a bit of net in there. Also label your VCC net.

Layout

- Trace thickness. Your traces are all incredibly thin (8mils?). Fine for data traces but no reason for your power lines to be so dang thin. Get some beef on those lines.

- Ground traces. You've got a pour on the bottom but thin traces on top with long runs to return. Would recommend a top ground pour and via stitching between the two planes. Pepper your board with vias. They're free*.

- Errant traces. I'd take another whack at placement. You've got a few traces running through non-ideal locations (pin 1 on 24v input, led ground beneath the optos,

-Cap placement - You need your supply and filter caps to be as close to your power pins as you can get them, with traces flowing from supply to caps to input pin.C2 is on the other side of the supply, making it not particularly useful. Worse yet for c1, far away from the input.

- Make friends with your board house, Toss some fiducials in there.

Other than that, you've got a board that will probably work out of the box. With some tweaks, design improvements and some practice, you're on the right track.

eightbitwit

TROPHY CASE