mmac_'s comments

Kicad is the best free EDA I've used and I know many others that use it. The active development and large community make it a no-brainer.

I use Altium professionally ($$$) and I feel like Kicad could cover most of the boards I work on. FYI I've seen a few advanced PCB's done in Kicad successfully - just not sure how much manual calculations/work they had to do.

Kicad + the cheap online PCB vendors are a killer combination.

It's ok, if you wait long enough it'll go back down to a small number. Or maybe a negative number and then the car crashes?

Please cap your numbers for both user experience reasons, and safety reasons.

Yes, have dealt with this before. Nothing like doing a fault analysis and telling someone that it'll fix itself in a few months.

A capped fibonacci sequence is a very common back off timer.

Chipset makers, probably correct but there aren't that many companies that make them. Depends on the analogue front end if they support the new frequencies.

I know the 3rd party module makers do tailor their modules to regions and the 'world wide' models can be quite pricey. On the region specific versions they don't include some of the hardware to physically operate on frequencies they don't specify. Sounds crazy, but a few cents here or there is worth running multiple SKU's.

There are probably other issues such as radio compliance and patents that also prevent an upgrade.

The VoLTE upgrade isn't so surprising. For a long time we had 3G/4G modules however the mobile networks didn't support VoLTE so everything would fall back to 3G. Once everyone got their act together, a quick firmware upgrade and VoLTE worked perfectly without adjusting the hardware.

Many of these SoC have HDMI directly from the IC without needing additional hardware converters. Something like DP you need a converter IC which adds expense and board space/complexity. Something like MIPI -> DP, I think TI makes some chipsets that do this.

The size is probably to save space on the board - looks like they try to keep to relatively the same size and mounting holes as previous boards.

I have an entire box of these mini-normal converter cables because of boards like this. OK when messing around but I can see the frustrations if you're not used to it.

You encounter this in older industrial equipment. Some of the old ethernet chipsets don't support automatically switching the pairs around. It's not really a problem since at least in our local area they need to be installed by licensed cablers who are used to dealing with legacy devices.

Many devices won't get updated until chipsets go EOL or there's some other compelling reason to do so.

Having said that, modern chipsets seem to all support it.

One of my earliest experiences with USB was back in the day where I had a PC without any USB front ports that were free. So I grabbed my USB thumb drive and reached around the back of the PC tower and plugged it in without looking.

USB didn't show up in the O/S. Thought maybe it wasn't formatted correctly and went through some diagnostics. Eventually went for the remove it / plug it back in technique. Had a look at the back of the PC and noticed I'd managed to plug it into an empty Ethernet port.... yeah they're about the same width give or take some tolerance. Also usually placed right next to each other.

Back on topic, I do find those bare/exposed usb keys (like a yubikey) to be quite annoying.

Often I see someone who will design something in CAD but not think about how the product will be manufactured. Design for manufacturing isn't a buzzword.

It happens with both plastic and other type of enclosures (metal etc). The better designers understand the manufacturing process and build their designs thinking about how they will be created in a production line. As others have mentioned, most manufacturers will say 'yes' to anything you request and charge accordingly. They'll just figure it out somehow, but you'll be unaware that you've doubled the cost of your part due to a lack of understanding of construction.

I guess it happens in other fields as well, i.e. architects vs builders in the construction industry.

This is solid advice. Find something you're interested in and go from there. If you can't find anything, maybe build something like a weather station. You'll start with a simple task: read the ambient temperature and display it somewhere (on an LCD, in a react app on the cloud etc). You'll then need to start solving problems, like how do you read outside temperature where you'll learn about batteries, wireless technology, water proofing etc.

Don't stress about the electronics and certainly don't be intimidated by text books. When you're starting out you don't need to really know the theory of transistors, but maybe a few youtube videos on the basics won't go astray. Think about if you were learning to code... would you read a book and start stressing about computer architecture? Some people might, but most won't. They'll hit up create-react-app and mess around with that.

When you're learning it's important to get instant feedback. Just learn how to blink an LED and you've completed the hello-world of electronics.

If you can code, you can do electronics. Same for the reverse. The skill sets are closely aligned.

I agree with the parent comments. You will spend an absurd amount of time making library components, and you can't trust 3rd party. The 3rd party sites are a great starting point to take out some of the grunt work, but you need to tweak them.

Your (cad tool) component library is your most valuable resource, and in my opinion more valuable than schematics/layouts. You have your own proven set of components that you know will work in manufacturing. Even the standard passive SMD footprints need to be tweaked for your specific requirements (ISO, design for manufacturing etc).

In regards to Kicad... great tool for 90% of designs. I would say as a rule of thumb, if your design can be manufactured at one of those online, cheap PCB manufacturers (for say, $10-$20) then Kicad will cover it. Once that calculator tool starts going higher you're probably doing someone more complicated that warrants the more expensive tools.

You can get a business account with Mouser/Digikey and then they just become another distributor. Your login gets discounted pricing (it's not much though) which is good for quick prototypes, and you can sometimes get an account manager to negotiate and troubleshoot directly.

I'm not sure how you qualify but you get to the point where you just RFQ to an email address and don't use the webpage. You don't need to be a $million+ purchasing outfit. They'll also schedule orders etc. at least I've seen Mouser do it.

Mouser is quite good on automated notifications - most importantly if anything in your order has changed (99% of the time it's a delivery date). Most of the other distributors do manual back orders in excel.

But their website is filled with annoying quirks. Here's such a basic use case: 1. Bring up a list of items from a search, say 100nF 0402 caps. 2. Sort by price low -> high (you'll see the icon, click that it'll work) 3. Now type in a quantity of say 100000 and find the best price on this part... yes the icon disappears when you fill in the quantity input field.

Download the CSV doesn't give price breaks.

Amusingly I just went to the digikey website which implements this functionality and.... something is broken. Can't even apply a quantity to a search. Also getting some strange loading page with a countdown clock... anti bot?

I would generally agree with this, however I do find the esp32 on the whole has been as reliable as any of the major brands (although haven't had to use an ADC). We don't drive them too hard though, but their cheapness has pushed the bigger guys to get more competitive on pricing which is a good thing. TI in particular seems to have sharpened their pencil a bit, maybe due to all their new fabs coming online?

The big guys still screw up, and over the journey I've noticed quite a few MCU subfamilies go EOL far before they should and it's usually due to silicon that has too many bugs in it. Maybe the big guys told them 'no' so there weren't any decent volumes on them anymore and they were forced to adapt.

Sometimes they're a bit more subtle. You've probably seen quite a few 'A' revision part numbers recently where they clearly keep the same MCU but fix the bugs. See this on other IC's as well.

For us, logistics (supply chain) and a solid support team are the highest importance. It's rare that we're locked into a single vendor due to a must-have-feature. These requirements narrow down our choices very quickly, and I'm sure it varies region-by-region (and how much $$$ you spend).

M.2 and PCIE style connectors are great for board-to-board connections. We use them all of the time in industrial applications. Super cheap and super reliable if you follow the rules. Very common to see all sorts of commodity connectors (M.2, USB, Ethernet etc) get used for non-standard uses.

Don't be afraid to use these edge connectors for hobby work - just make sure to get the board thickness correct and don't stress too much about the gold finger plating. If you aren't inserting too often, then a basic 2U should be fine (you don't need super-expensive 32U etc)

Of course when you're dealing with a user-facing connector, follow the rules and don't cheap out or be lazy.

yeah this looks correct and it's a different world if you have direct access to the modem IC.

To clarify I was referring to the modules that the average person can get their hands on. If you rip open the module (or look at the FCC paperwork) you'll likely see a Qualcomm chipset underneath. It's just a level of abstraction really.

You generally pick one interface and do everything on that. The modules are still using old school AT commands (so you still send ATD to dial a phone number). Yeah the 4G uses the same AT interface over serial.

You picked up the drawback: speed. You can't pump 4G speeds over a serial port. Depending on what you're doing through, the 'slow' speeds you get over a serial port are more than enough to serve your purpose. The 4G part is about connectivity and not speed in many cases. Locally we're seeing 3G shutdown and it won't be around for much longer.

Obviously better solutions exist for low data usage over cellular - have a look at NB-IoT or LTE-M.

Most people will be familiar with RS-232 when connecting to a computer (COM ports). In the industrial/embedded world, it's still used quite a bit to connect to devices for logs/terminals/programming and setup etc. Of course now we rely on usb-serial adapters to connect them to our laptops.

RS-232 is still used for connecting to some embedded chipsets. Best example would be modems/4G modules. You can pick either RS-232 or USB, however sometimes on that little microcontroller you're using it won't have USB. If you don't need a huge amount of throughput then the serial port is fine.

RS-485 as others have mentioned is great. Often you can't run new cables for cat/fibre so you're stuck with stealing some copper off an old system that has been decommissioned. You'd be surprised how far you can run a RS-485 system at low speed and maintain high reliability.

As someone who cut their teeth in embedded before going into web development, I've seen a significant amount of similarities between the two. The most obvious to me is that now we spend a lot of time connecting prebuilt libraries together - back in the day we wrote everything from scratch. The skills required to interface to a bluetooth library are not any different to say connecting to a map API on a web page... if it all works and does what it says in the docs. At some point your core skills and experience are required in the specific domains to identify and fix bad behaviour (i.e. your bluetooth library isn't working because you have physical antenna issues etc).

There is also a large amount of crossover as embedded gains more resources. Often you're working with javascript because your device needs to have an embedded web server with custom functionality. Sometimes you see SQlite on embedded flash, although debatable if they really needed it. Running Linux is far more common and it works pretty much the same regardless if it's on an MCU or a VM in the cloud.

The main difference I see is to do with the ease of fixing mistakes in the field. With web development I can usually git push and the issue is fixed for all users. With embedded, I almost never have an internet connection so it's a case of physically sending people to site or product recall to fix the issue if it's serious. Internet connections are becoming more common in embedded so we can remote update, but still the minority in general.

Lots of common ground, but just like any discipline it's that last 20% that makes the difference.

A bit of a generalisation, but I tend to find when a traditional EE writes firmware, they treat the firmware as controlling the hardware and are more direct with their instructions. i.e. if they need to set a gpio they will often do it directly rather than abstract it. So an EE will write gpio23 = 1, whilst a more software background person will create some type of function say, turn_amplifier_on which will then take the appropriate action.

For those tiny projects it doesn't matter too much. However it seems with demands for features/time to market we rely more on vendor supplied SDK's so this direct approach is becoming less common.

I do find the EE's to be great at bitbanging though, especially when timing is critical.

Single pair communications are invaluable in industrial applications - almost all of our scenarios involve the restriction of not being able to run new cable. The costs involved in running new cables can be eye watering to say the least. If you're on a greenfield project, then there are surely better solutions since you have the luxury of designing the cable runs.

VDSL has been king in the areas I work in for quite a few years now and has been very reliable. We are experimenting with SPE and it's looking positive with the biggest benefit being cost. SPE for us is a significant cost down that will allow us to design it into more products where VDSL blew the BOM budget. We'll still use VDSL when we need higher bandwidth but only have that single copper pair.

SPE fills a gap where you need a decent amount of bandwidth at a reasonable distance for a low price. For us it complements modbus, standard ethernet, vdsl etc.

SPE is also very new with the chipsets really only starting to become available in the last 12 months or so. Chip shortages aren't helping but expect to start seeing these solutions pop up all over the place.