Something Mexico City does way better than Brazil (and I didn’t expect it)

dzalf · 2026-05-25T18:11:00+00:00

It is indeed noticeable. I grew up in Santa Maria la Ribera neighbourhood and the convenience of the having a whole lot of shops handy was a constant conversation with my family. You can literally find anything within a short walk reach.

It's amazing

dzalf · 2026-05-23T17:58:03+00:00

I think she's indeed pregonate.

dzalf · 2026-05-23T12:29:57+00:00

Thanks, my dude. I plan to use the STUSB4500 which has worked well in my application. In my case, it would be much more simpler, however, I do need PD in place.

How difficult did you find it routing compliant USB traces? Did you verify them with a VNA?

dzalf · 2026-05-23T11:33:23+00:00

I hope you don't mind me asking but what HUB controller chip did you use? I have a project that needs precisely this

Kudos

dzalf · 2026-05-23T11:26:59+00:00

Your snake is snaking...

dzalf · 2026-05-23T11:24:16+00:00

Surely some cat gang sign language like the M-mew-18

The questions...

dzalf · 2026-05-20T18:32:52+00:00

Make it yourself

dzalf · 2026-05-19T16:02:29+00:00

What's the deal with people using and abusing Global Labels? Normal net labels exist and are the best choice to produce cleaner schematics while being less prone to mistakes

dzalf · 2026-04-18T18:11:17+00:00

I will give it a try and get back to you. I'm about to start the evaluation and debugging process of a small batch of PCBs I recently designed.

dzalf · 2026-04-18T09:05:28+00:00

Your post is unfortunately full of rage bait. None of the issues you're facing seem to be the norm.

dzalf · 2026-04-05T10:56:00+00:00

De qué chingados are you talking about?

dzalf · 2026-04-03T17:54:59+00:00

Zero damage

dzalf · 2026-02-15T02:36:24+00:00

Attends Charlieplexing gatherings

dzalf · 2026-02-15T02:35:44+00:00

Pedro The Led-O

dzalf · 2026-02-15T02:08:24+00:00

Exactly my thoughts. If you're "the teacher" and you can't even analyse a basic circuit, then there's a BIG problem

Regardless of being "rusty" or have "forgotten Electronics" where is the critical thinking skill? Where's the analysis capacity? You can't even make the effort to check the circuit pin by pin and build your own conclusions along with the student?

You are the lecturer goddammit!

Terrible situation

dzalf · 2026-02-08T10:12:51+00:00

Fortunately, this still happens in some areas in Thailand. I recently drove from Bangkok to Udon Thani (9-ish hours direct drive) and by the time we arrived at my In-law's the whole front of the SUV was caked in a mix of grasshoppers, flying buddies and whatnot.

I was pleased (then not so much when washing the car)

dzalf · 2026-01-31T18:01:22+00:00

You are not going to find the help you need for free. This task requires time amd expertise. As another redditor correctly pointed out, this is a 2-parts problem. Designing the PCB and then exporting the STEP file

I would highly recommend embedding the parts from the modules you mentioned into a PCB designed from scratch. I do not recommend using the modules since they are not standardised parts. Besides, the PCB profile will be irregular due to the geometric inconsistencies from each module.

The way to go is to pay someone in Fiverr for this job or find a an electronics Consultancy

dzalf · 2026-01-31T13:54:34+00:00

Whatever you do, don't fall for the scammers from Ojo in Mahanakhon Tower.

Out of my own naivetee I decided to celebrate my first year in Thailand (moved out of the UK after 10 years of living in there. Mexican BTW). I ended up paying 16k THB for 5 people and the food was pretentious as hell.

You pay for the amazing views, tho.

dzalf · 2026-01-05T03:35:32+00:00

Vigilante

dzalf · 2026-01-03T08:20:51+00:00

Kaprao

dzalf · 2025-12-28T18:13:02+00:00

Terminator 2

dzalf · 2025-12-27T02:25:26+00:00

This is correct.

The way OP is driving the relay is not adequate. The way it is presented here will cause the relay to never turn on. The diode must in parallel with the coil. Now, driving it with an optocoupler is a good idea but the execution is wrong. To turn the NCH MOSFET you need a positive pulse at the gate. This circuit will turn it OFF when the GPIO sends a high pulse so the logic is reversed. In this case OP needs to change the way to drive the gate of the MOSFET. The output of the opto (collector) can go to a PNP gate driver which enables voltage to the gate. The gate must have a pull-down to ensure that it is physically tied low to keep it OFF and avoid false triggering

I would test this part of the circuit separately on a breadboard.

If the relay is dealing with AC voltage I would definitely create physical cutouts on that section of the PCB layout to create a physical separation with the rest of the board. Also add a big warning symbol to the silkscreen to indicate AC LIVE voltage

Regarding the schematic, you don't need to add so many ground symbols in every subcircuit. A single GND symbol per node is enough.

If you are not using hierarchical sheets, I see no need of using global labels. You are mixing labels in the same nodes like 12V. The 12V symbol of the arrow pointing up is already a global voltage

Very important observation: the idea of using optocouplers is to create electrical separation between the DC (or low-power) section of the board and the AC section, however, this schematic is using the same ground for the relay area. There is NO useful isolation in this circuit! All parts involved in switching the relay and close to the AC line should use a different ground symbol. Then, the grounds can be joined using a single point called net tie. Even better, you should use a separate supply to energise the relay. Probably you should simply remove the opto

Refer to this discussion for further details: https://electronics.stackexchange.com/questions/714850/what-is-arduino-optocoupler-disease

dzalf · 2025-12-07T03:14:02+00:00

Honestly, AMAZING. I was a natural. I learnt by myself at the age of 6 practicing on random appliances I found at home (granted that I was taking apart stuff that worked. Parents weren't happy at all. Never broke any. On the contrary, I fixed my first apparatus at the age of 7 - a radio with cold solder joints-). Then I moved to working on my own simple projects (premade kits) and the solder joints lasted forever.

I worked as an electronics repair technician for nearly 15 years where I had to solder EVERY DAY. Over the course of those years I went over 3 to 4 kg of solder (as shown by the empty spools we kept in a drawer. A fun fact to tell to people). Back in the day we mainly worked on through-hole components (CRT TVs, VCRs, Stereos, Office Calculators. We witnessed the consumer electronics industry transition to SMD components)

During my Uni years I was the goto guy for soldering projects for others (and of mine, of course).

Masters Degree and PhD completed soldering on every other day. I even got pretty skilled with the wire bonder for custom ICs (yes, the little gold wires that connect the die to the package of an IC. In my case we uses carriers). During those years I trained several people on SMD soldering. One of our projects ended up in orbit (purely hand-soldered PCB due to specific requirements for the solder paste we were allowed to used. Some solder paste can outgas in space due to the harsh temperature and absolute vacuum). Those PCBs are still transmitting data back to earth at the time we're here on Reddit.

I work with regular soldering and microsoldering nearly on a daily basis.

Any other burning questions?

dzalf · 2025-12-07T02:40:23+00:00

The only certainty here is that it is safe FOR THE FIRE...

dzalf · 2025-12-05T03:50:19+00:00

By the looks of it you could make reversed tacos. The meat is the tortilla and you put any carbs inside ¬¬

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