Joey Castillo's No Muppet When It Comes to Time Management, Back with Two New Oddly Specific Objects

Some people just seem to find the time.

Whereas for some of us, there never seems to be enough of it. Time to get up and out of the house every morning. Time to get the list of tasks laid out for that day checked off. Let alone the backlog from yesterday's list...

So when people mange to turn out some top-tier tech, on top of the two-foot long to-do list, well — comparatively, sometimes I personally can feel like a bit of a muppet for not making good on my planned schedule of projects.

No matter though, because these days, It's more my thing to write about all the wonderful project work that whizzes past my screen — my Twitter timeline is happily filled with all sorts of weird and wonderful works of engineering art.

One of the first significant projects I was fortunate enough to be able to cover was that of the OSO Open Book, an Oddly Specific Object from Joey Castillo. This open source e-book reader looked to free many from the bindings of DRM, enforced by many commercial platforms.

That was a little while ago now...

While I think I've managed to polish off perhaps... two(?) of my own personal projects since we first published the piece on that prototype OSHP ark purple PCB rev of the Open Book, Castillo has been a mainstay stream of innovation and inspiration of "get it done" ever since.

Can do — times two!

The latest pair of PCB designs to be derived from Castillo's Twitter feed come in the format of this illustrious duo, affectionally named Bert and Ernie.

I think all I can say — without being sued — is that the resemblance to a certain well-known set of characters who may or many not resemble the duo heading up this article is, well, uncanny.

Right now, this platform looks set to perform as the prototype from which future works can spring forth, and as with a lot of what Castillo does, it's all about testing out new technologies and ideas, and there are one or two features on these fresh new designs that are pretty damn funky — let's check 'em out.

Memories of massively discounted MemoryLCDs...

A few weeks back, there was a bit of a hotcake sale over on one of the "Electronics Twitter" threads — whereby someone was able to afford these normally premium priced pixel panels for something like one-third of the distributor prices you and I would pay for the volumes we use.

It's never nice to hear that someone has had a project canceled, but we are so very fortunate that RWB made these available to us, rather than the usual e-waste or eBay price gougers.

With a new display to play with, the you could be forgiven for thinking that this is simply and evensmaller version of the OpenBook, and it's already ant-sized sibling that are available for perusal up on the pages of Castillo's GitHub.

And on reviewing the schematic — admittedly, slightly re-arranged for visual purposes - indeed, there aren't many major differences to the core architecture — if it's not broken, don't fix it.

At the core of the circuit, Castillo's favorite bit of functional silicon, there sits the Microchip SAM D21G, along with many of the same peripherals we are familiar with from our previous deep dives into Castillo's work.

With all the typical net names, akin to those previously seen on the schematics of the Oddly Specific Objects so far, there are few new net names that need the be pointed out — because the SAM D21 has a pretty special peripheral that we don't often cover, but perhaps that might change, with the demonstration it's about to enable.

The ABC's of the SAM D21 PTC

Under the hood, the SAM D21 is packed with more than a few peripherals, and a fairly flexible pin mapping matrix, save for a few special function pins, ones that usually serve purpose reserved for the "good stuff".

If we closely compare the various net names nestled into the I/O of the D21 pins seen in the schematic above, and some of the older OSOs, we see some pins we'd more commonly expect to be associated with, say a touchscreen.

This pin array, with names prefixed 'X' and 'Y' do indeed indicate a touch of that sort of interaction going on, but the way in which it is implemented is almost magical.

First up, let's look at where those net stubs end up. You see that somewhat odd arrangement of nets and junction names — somewhere towards the center of the full schematic?

Let's take a closer look at that.

Schematic. Zoom. Enhance. Crop.

If you are left scratching your head at what this layout of lines is looking to do, well, let's take a look at what this looks like in real life.

This 2D array of copper pads forms a matrix of elements, configured as an array of rows and columns. The X and Y nomenclature suddenly becomes clear.

If you look at the AfterDark finish board, with its clearly-contrasting copper on the black FR4 substrate, you can clearly see the rows connected horizontally, with the columns connected through vias on another layer.

Great, so we've got some very fancy looking front facias — the patterning alone could make this something you'd like to incorporate into your next illustrious looking design. But oh no, this is far more than some PCB artwork.

Roll on with the witchcraft!

Check the GIF below and get ready to have your mind blown.

It is exactly what it looks like — magic. OK, no, it's not, but it looks it, doesn't it?

Legitimately, shown below, is some of Castillo's code, so although it looks like magic, and with clear evidence of such practices in previous git-pull requests... well, no.

This is just some sufficiently advanced technology, masquerading as such.

That array of elements of filled copper squares, although unassuming in appearance, functions as a full 2D trackpad.

"Functions" feels like a bit of an understatement — for a first spin, this is pretty freakin' good, you've got to admit.

This magic is made possible at the core of the SAM D21 thanks to the PTC (Peripheral Touch Controller) — but there has been a lot of talented contribution from a few other folks — that fortunately for us, makes this all much much easier to pull off.

Programmatically placing polygons thanks to PatternAgents

While I'm not aware of a KiCAD port (yet), EAGLE users such as Castillo can stand to benefit directly from the Touch Widgets Library for EAGLE, from @PatternAgents.

Their neat set of scripts can programmatically generate and place the polygons that would otherwise leave a lot of head scratching and calculation to manually coordinate.

And though I say EAGLE users can benefit directly, there's little to stop you from getting your widgets worked out in EAGLE, before making use of the all-too-handy ability of KiCAD to aptly import your freshly worked out widget.

Adafruit_FreeTouch makes this functionality a Free-for-all!

Adafruit has almost synonymous with the term hardware when it comes to open source.

I dare say I see more references to "Feather" than "*duino" on the Twitter feeds these days.

Lesser considered perhaps is the immense amount of code that the Adafruit crew churn out to compliment their hardware. Drivers, examples code, heaps of helpful how-to guides and hell, even entire frameworks have fallen down from their fingers, free for our use.

Once such library is the Adafruit_FreeTouch library, that enables the native PTC controller of the SAM D21, abstracting it to a class that returns the 2D sensed positions from the scanned array!

Speaking of frameworks, there's even a CircuitPython implementation (touchio), the codebase of which contains a cross-platform pin scanning algorithm that allows this driver to to dive over to other MCU and code platforms.

That should come in handy with Castillo plans to pump up the jams with the substitution of the D21 for it's beefier, bigger brother, the E51, albeit — at the cost of forsaking the on-chip PTC engine. No fear, the CIrcuitPython algorithm manages just fine!

The open source community is truly something else — it's remarkable to consider that we are fortunate enough to have so many people who share our interests, and who are able to contribute all of this incredible code and hardware for us to build upon and learn from.