Glen Akins Is on a Roll with His Latest Creation, the Sushi FeatherWing!

We picked up on a tweet a little while back, regarding a curious new gadget aimed at the kids toy market was clocked by a keen-eyed hardware hacker — @kakocom.

Thankfully, this isn't going to be an article ripping apart yet another poorly designed, IoT-connected, kid-accessible product — hoorah!

Instead, it's a look into how yet again we happy hardware hackers stand to benefit from the economies of scale at play when marketing a hardware platform in such volumes as the one we are about to take a look at!

Wand-ering what I'm on about?

Credited to Cepia LLC, this range of "magic wand" toys is jam-packed with interactive elements, not least, the rather unusual "ultra wide letterbox" aspect ratio RGB LCD panel that can be seen stretched along the side of the toy in the photo below, showing some of the various models available on the market.

This LCD is the first of its kind that we have seen in such an odd form factor, and certainly steals the attention away from the panel that could easily be initially overlooked, sat in the center of the hilt of the wand.

Let's get a better look at that letter box!

Owing to a wonderful stash of photographs Kako took during a detailed teardown of one of these units, interest was immediately sparked when people saw just how complex the device is — not just in terms of function, but modularity as well.

It's a veritable treasure trove of LCDs and various other components, looking like it was sent to market with some potential cost optimizations left out of the process. The visibility of connectors is joy to our eyes, it means we aren't going to risk ripping things apart and damaging them in our dissections!

The major point of interest is the ultra-wide aspect ratio RGB LCD panel, so let's dig down and take a look at how it's hooked up and how it works.

Stretching the boundaries of display form factors!

First up, ultra-wide aspect ratio is no exaggeration. With a resolution of 320 x 96 pixels, it poses some interesting challenges as a GUI element, but we're keen to see what people come up with — we could hope for a touch-enabled version in the future, perhaps paving the way for a hobby-level apple touch bar for those so inclined.

We can see an example of some of the graphics it displays, sourcing the appropriate media from whatever production firmware is loaded on to that specific version. There appear to be resource packs tailored to each wand in the photos we've seen online.

These resources appear to be stored on an internal micro SD card, rather than a soldered down SPI flash — an interesting choice that certainly fits with the presence of FPC cabling and connectors, rather than direct-attach wiring. There are certainly savings to be made when looking at the BoM of this toy!

It is telling that there was some expectation of cost optimization from the designer, such that you can just see the footprint we've seen somewhere else before, poking out from under the SD card holder.

Some call it cursed, but co-locating this footprint will often work in-situ with one of a uSD card socket, such that the socket can later be optimised out.

A uSD card will survive reflow just fine, as we often see in cheaper memory sticks, that use this trick to repurpose SD cards into USB memory sticks using a simple host PCB.

Driving both of the panels is done by a 32-bit Cortex-M0 (we think) — a Sonix SNC73121.

This looks like a powerhouse of a part, if even from a brand that is lesser seen over this side of the pond. It might be worth checking out LCSC for a few of these, they look very capable indeed!

Kako's blog veritably details the flurry of work that has been going on in deciphering the digital signals needed to drive this Dachshund-dimensioned display,

Even with all hands on deck, it's still very impressive to see the how quickly we have had Glen Akins treat us to his super-simple, single PCB FeatherWing, named Sushi — for reasons that will soon become clear!

It's certainly a straightforward affair, but serves to give your Feather board of choice the ability to reliably connect to the fragile FPC connector that extends from the display controller.

Looking at the routing, Sushi really is as simple as it seems.

Sometimes it's really worth emphasizing the importance of the simple things that can save us hours (or worse, days) of debugging loose connections and other "ghosts in the machine!"

Given the madness in how this display is internally mapped — a 640 x 48 array that draws two lines of 320 pixels at a time, maps out to the 320 x 96 pixel

So, why Sushi?

Well, we'll let the demo code we speak for itself! It's not often you see such an array of sushi, at even the most well stocked of sushi bars!

And what the heck does all that hexadecimal work out to? A delicious looking demo reel for this elongated LCD!

While the supplied code repo from Akins ties this together nicely for use with the ESP32 Huzzah Feather, as does the hardware itself - with pin mappings optimized for that board, the original code and graphics - courtesy of @pcjpnet, should be fairly adaptable to any modern MCU you can muster!

I'm still scouting for the display as a standalone purchasable item from the usual sources, so sit tight on that one — I'll update when I do — but if you're keen, and have already hit "order" on whatever supplier you've found stock of one of the wands from, well, do yourself a favour and grab yourself a Sushi board straight from OSHPark here.

Once that's done, check out the GitHub repo from Akins to get a grok at the code, and the required FPC connector to get Sushi slinging data at your display!

As always, Akins is on my list of Twitter picks to keep an eye on, so do yourself a favour and give him a follow if you haven't already — @bikerglen.