Comment by grues-dinner
6 months ago
> 99% of PCBs designed are fairly basic boards implementing the reference design with some small tweaks
This may be true of hobbyists, but is very much not true in industry.
Maybe all those millions of IoT devices skew the number of PCBs made that look a bit like an ESP32 plus a button and an LED, but most unique designs probably aren't those. Endless march of things like new super-dense PC/mobile motherboards and all the weird hyper-specific industrial electronics takes far more effort, say.
And no one is sweating the few days to design and lay them out to meet the constraints for a simple ESP32 + a button. Primarily the size and shape and power usage. That's not the hard bit of slinging mass-market IoT trinkets, the software side is.
I did work for a while in/with a small hardware company, and basically how we did things was we integrated a complex off-the shelf CPU board, to a custom 'host' board that housed application specific logic.
Signals integrity analysis used for integrating DRAM is a difficult skillset, requires trial and error, and if you manage all the design complexity somehow, manufacturing is likewise difficult. If you show up with a 8 layer PCB littered with BGA components, most manufacturers won't talk to you if you don't have volume or aren't willing to pay astronomical prices.
And let's not get into wireless - antenna design and interference testing is its own dark art, and even if you manage to make something that works, you have to certify it in every single country/economic block you want to sell to.
And all this to supplant a ready-made Pi Zero or ESP board. that costs basically nothing.
Clearly much bigger shops than ours have realized this - there are many high-volume commerical products that use a Raspberry PI as brains, or smart speakers using ESP32.
I assume your application host board wasn't two LEDs and a button. Using a module is one thing, using essentially only a module is another.
My point is, laying out very simple hobbyist-level designs is not 99% of PCB design effort in the world (the original claim).
It's not "envelope-pushing crazy designs" (per the original) to have 500 or 1000 or more components on your board even if you do use a module to offload the CPU and radio (or the field bus in industrial contexts). That's just normal levels of complexity.
And even if you do make a boutique smart speaker with a module and can afford it because it's a high-end device with margins, if you get to real volume, saving a dollar a unit by integrating might be worth it: you can still see change of out the savings after getting a design consultancy to redo your board if you're shipping millions of units.
It is absolutely true for industry.
It's not just IoT. Look around you in your daily life. Your average person has a few super-dense complex PCBs around them (laptop, phone, maybe a TV etc) but they have at the absolute minimum a few hundred simple PCBs. Your average household doodad these days requires multiple PCBs (power, control, and communications are typically separate.) How many things do you own with LEDs in them (including your lightbulbs?) How many modern cables do you own - because they all have PCBs in them now! I recently tore down a popular non-smart home appliance that's basically a fan, and it has five PCBs - one power, one control, one for the buttons on the top, one for the buttons on the side, and one for a sensor, none of those were off-the-shelf, and this is not unusual. If you really want to lose your mind, look at cars or children's toys, you'll go insane. Your average American with a car and an apartment, or a modest selection of modern children's toys, will own well into the four figures of simple PCBs. I think it's quite rare for your average person to own more than a handful of phones and laptops.
Beyond consumer products, still the overwhelming majority of PCBs are very simple. You say "all the weird hyper-specific industrial electronics" yet go into a sheet metal shop or a train factory or a refinery and count the ratio of simple PCBs to complex. Every sensor, every lightbulb, every cable, every scanner, every connected device... look at how simple process control is for most processes, or how simple most PCBs in most motorized devices are. The employees' smartphones will be the majority of the complex PCBs on the floor.
Now that I think of it - I don't think it's possible to buy or use a complex PCB without multiple accompanying simple PCBs. They virtually never take 110v, they typically take 110v->USB-C->5v DC, so that's two simple PCBs for power conversion plus two USB-C PCBs. You might use the device with a display (countless simple PCBs, its own power etc) or a mouse (yet more...) or some earbuds.