I'm sure many of us have things to say about the pin layout on the ST Nucleo boards - I reckon most of it isn't very polite, either, as the layouts seem to be designed with active malice. There are no places where all 4 outputs of a timer are next to eachother. Of the 5 sets of pins that can be UARTs, only 2 are grouped (and one of those is the console) - despite the fact that all the uart pins are on consecutively numbered pins. Why is B7 over in the middle of nowhere? Why is it B453 instead of 345 or 543?
Not only does the layout make not a lick of sense, but they didn't bother to label it in any way, so you're counting pins. What, are we supposed to use some breakout board? Because they don't seem to sell any!
I don't get it, I don't get it.
Wow! I haven't half your knowledge or talent, and then I see your poor soldering iron. Like Michelangelo painting with toothpicks, while I have the best boar bristle brushes but can't paint a stick figure.
Please tell us how you made that board! I know it's probably simple to you, but out of my understanding atm. I'm guessing you could just post a link...
Are those cross-braces in the first pic? To hold it steady while you ????
What is the metal sheet for in the second pic? Soldering?
What did you coat the traces with in the third pic?
That soldering iron has seen better days, but it's flaws are only cosmetic - it's a really nice soldering iron. Weller, one of those ones in the ancient off-blue-green housing. Actually, I think it's had that tape on it since before my father got it - that doesn't look like his style of repair.
Board was fabbed at home using toner transfer method.
There are many other sites that describe the process in more detail - that page more sums up which choices I make, and repeats the important bits.
It was reflowed (not entirely successfully - I had to touch up a lot of joints by hand, because the paste hadn't melted) in a converted toasteroven using the ControLeo2 controller (and associated build kit). Said reflow oven perfectly reflowed two boards last night though, so I'm still not sure what's going on.
The crossbraces were meant to hold them in position during reflow. Luckily, this turned out to be unnecessary, particularly since the crossbrace headers melted. You certainly need them to position it correctly, so they're parallel and stuff. That's surface mount header, so it can be soldered down cocked if you're not careful.
Metal sheet is nothing special, just what I carried it up from the reflow oven on, since it was still a bit warm, and i was impatient to start soldering all those joints the reflow oven missed. STILL better than hand soldering!
I coated the traces with clear nailpolish (yeah yeah). I usually tin-plate my boards, but mine has stopped giving a decent coat (ie, it's used up), and I don't want to crack open the next batch until I have to, and I didn't feel it was necessary here. If it was going to be sit around and be soldered to in the future, i'd tin it, but since this will just be soldered once, and then sit there, i didn't bother.
The labels were made by saving and hacking up the board reference page to display them in different rows, then printed on sticky-back paper, stuck on, and then painted over with two layers of clear nailpolish to protect from spills, stray solder blobs, etc.
@Manxome, @DrAzzy - I was going to remark about the soldering iron... I've got a very similar Weller one - I've had it for 25 years and it's still going strong :)
It's a really nice board - I really ought to spend more time doing single-sided stuff (I always did mine with a marker pen and a plotter, and never got results that were as nice as that). With surface mount components now you can probably go pretty far without having to drill any holes (especially with 0 Ohm SMD resistors when you need to cross tracks).
I can't wait to see what you get up to with the castellated Picos :)
By the way, were you aware of the Nucleo class? Not much use for what you're doing, but it'll let you access the Arduino-style pins a bit more easily.
I was aware of it, but I hadn't looked at using it. I only own one arduino shield, so it wasn't a big draw for me.
Very thoroughly detailed explanation, thank you! Lots of materials needed and lots of time I bet, something not undertaken lightly, but very nice results.
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