Draw me to the moon…

…Led me sweep among the stars

 

So, I have a long therm project that will require a display with some particular needs.

I want it to work with 3V3, retro-looking and curved.

Yup, nothing off the shelf is going to work for me (flexy o-led displays with a big aspect ratio are not going to be a thing in time, and they don’t exactly look the way I want the thing to look anyways.

We could say I want to inspire the display in these:

The gorgeous HDSP-2000’s wich are nigh impossible to obtain nowadays at good pricings (and besides, they are small for my application). But the amber dot matrix look is just too gorgeous to let it pass, so I started drawing my concept:

8×8 groups of leds, using a SN74LVC244 line driver as row selector, and 74HC595’s shift registers to select the columns using a clock signal (and a start pulse). The thing is, when I started this, I was not sure I could program a microcontroller well enough to actually use such a display (for some people it would be awalk in the park, but to me, programming is always a chore I don’t particularly like to do). Of course, since this post doesn’t have a doomed kind of tittle, and I’m actually writing this post, is fairly evident I succeeded.

Oh, sorry, spoiler alert. XD

 

 

Anyways, so I just put myself to Altium the shit out of this thing, one schematic at a time:

Then PCB it:

Damn altium. XD

For a moment, I was also afraid I would have to chase every individual led, however Altium was kind enough to group them in couples of 8 leds:

At first I just put them horizontally, altough I knew I was going to rearrange them to be as compact as possible (1206 led footprint):

90º rotation and compaction afterwards:

The other componentry:

It’s not like it’s a particularly difficult board, but I spent an insane amount of time compacting it for a 2 layer board. (remember, this is a prototype to test my programming skills (and secondarily. that the circuit worked).

8 row input lines, a clock input and traveling pulse input.

And, since I was at it…made it BLACK:

Nope, there was no way of avoiding those three jumpers without heavy board remodelling, and I was tired of it already. Two weeks later:

First, a bit of testing:

Once I was satisfied I assembled the rest, and lo and behold!

Consumption is moderate at 40-ishmA, as per design.

However, not everything was perfect in the land of the led. Previous tests where only lighting one led at a time sequentially, and that is innefficient both because I designed a parallel load, AND because reduced overall light intensity per led. Given that I was already working at very low levels (5/8mA per led) reducing it even more was not going to help with visibility. When I tried to start doing more, this happened:

 

That line was supposed to be one led thick, but somehow, the line was doubling horizontally.
Hummmm…
Quick check with the scope:

LMAOOOOOOOOO, no wonder the leds where doubling, I had made the software in such a way that it put the (blue) led activation, in between column pulses. XDDDD
Some softwareing later:

Nice and cozy!
Beautiful pulse-within-pulse (blue led activation, yellow, column selection).

After some more fiddling with the STM32F103:

BAHAHAHAHAH…Had to be done, sorry-not-sorry. XD

Some more poking:

The software side, in the next post, folks!

See ya!

You know the drill.

Or maybe not…

CNC drill, stahp, you’re broken!

Also note the crappy edges in the central square.

Concentricity.

So, I was making these spacers to align some boards into an adhesive backing and I would like to point out that if you ever do something like this, you MUST NOT lathe the recess using the hexagonal body of the spacer. If you do, they (lathed part and center of rotation of the screw) will be very misaligned (up to 0.5mm).

Use, instead, a screw wrapped in copper foil to attach it to the chuck, then lathe away until you achieve the desired diameter. (2.52/50 in those). Also, be careful to make shallow passes or you might bend the screw and mess up something.

(yeah, not much electronics lately, I know. Just wait for it, I’m preparing something really cool, continuing a previous project)

SkyFall

This is the end
Hold your breath and count to ten
Feel the earth move and then
Hear my heart burst again

For this is the end
I’ve drowned and dreamt this moment
So overdue I owe them
Swept away, I’m stolen

Let the sky fall
When it crumbles
We will stand tall
Face it all together

Let the sky fall
When it crumbles
We will stand tall
Face it all together
At skyfall
That skyfall

Skyfall is where we start
A thousand miles and poles apart
Where worlds collide and days are dark
You may have my number, you can take my name
But you’ll never have my heart

Let the sky fall (let the sky fall)
When it crumbles (when it crumbles)
We will stand tall (we will stand tall)
Face it all together

Let the sky fall (let the sky fall)
When it crumbles (when it crumbles)
We will stand tall (we will stand tall)
Face it all together
At skyfall
[…]

This is the end…

Or…is it not?

A story ends…a new stage begins…

I will soon be moved off from production to become a SMD machinist. I’ll be heading towards controlling not one but three SMT assembly lines. I have no fear in me from long workdays and odd hours, but I keep wondering what will happen to me. Will anything from the old me remain when the training is over and I’m on my own?

As said, I have no fear, but I do contemplate the fact that I might burn up quickly. I’m not sure my bosses take that into account.

I haven’t chosen the song lightly either. When it says we will “face it all together”, it’s because as long as I’m able, I am going to keep a journal, both in video and text, of what it is to become a machinist, what do you do, what do you learn, and if I burn up, you’ll see my fall.

On the other hand, I wonder if my new boss fully understands what he’s got with me. He hasn’t done any interviews, as I have been just hand picked. He barely knows me, just that I like machines, machining, electronics and stuff…but that I also don’t see my bosses as superiors but as equals.

If I see something wrong, I say so. I will always spoke my mind. I will also work more like a robot than a human (I don’t drink coffee, I don’t smoke, so I don’t loose time in nonsense. I like efficiency above everything else, and I don’t waste my time at work, or if I do it, it is in a fully approved way by the A.S. Enrichment Center).

It is interesting because I am going to apropriately meet him in a road trip across the country to get the machines. I don’t know if sitting in a car for 10 hours with your future boss is the best way of being introduced to someone.

Also, he doesn’t know that this is a reverse job interview. He doesn’t have to like me as a worker, I have to like him as a boss, otherwise I’ll pass the offer along to the next coworker who is adequate for the job. I’m not sure either where this self assurance comes. I know the job must meet some basics like let me play around, document things, carry my bag-o-tools, mount my own boards, use the tools for my personal projects, etc…plus some extras I plan to add to better fit the job timetable to my needs. Basically I don’t especially need more money (altough I could use it for something, sure.) and I don’t need being stressed, yelled, forced to overtime and work outside a normal job envelope. And since I don’t need that, I feel free to say no if all that doesn’t come with a set of bonuses and benefits as big as a mountain, apart from the money, I mean.

Of course there are still posts to be written (and some drafts to be published too) about the laser, the CNC router and if I ever finish the 3D printer, that too.

Because of too much KSP, I just feel like going too fast in a reentry…

Leftovers.

Diogenes syndrome at its best:

Do you see anything interesting in this board?

When all is said and done…I do!

Leftovers!

I use them all the time for many things. On top, spring loaded supports, below, an improvised L-shaped support. Milling is good enough to accept that as a reliable 90º bend.
Also, sanding, drilling and cutting give you a vast array of tooling for support, extraction and whatnot on your daily technical life.

Short.

It’s hard to do visual Quality Control when you are doing 3.000+ boards, so it’s no surprise this slipped the person in charge:

(Find it)

And this is your board on shortcuts:

We were producing so many of those, I didn’t bother repairing that, altough I could.

Tin Whisker

Of course this doesn’t have anything to do with the satellite killer, but it is surely going to avoid being detected in visual inspection:

Here’s it’s big brother (same production run):

I wonder if someone’s hair got covered somehow in solderpaste and it just shortcircuited everything…(it may not be even possible for a hair to survive oven temps, who knows?)

All the wires were cut and the boards worked fine.

Pads!, Pads?

Manager: “Board doesn’t work, find the broken track”

Yeah, does that count as “broken track”? XD!

Board was totally irrepairable, of course.

 

For the ones who didn’t get the tittle, I’ll just say I love misquoting the late Sir Terry Pratchett. XD

Scotch Brite

Someone, somewhere, had fun with it…but it wasn’t us!

(side by side comparison with a “good” board)

These are midpower boards, so heatsinking doesn’t have to be as good as it can be.

ATCHOOO!

Who could have guessed that pick and place machines could sneeze?

XD!