I got a new keyboard!

This is the PlayRight my first smart tablet. It's apparently a walgreens exclusive.

so the way it works, it has four modes:
alphabetical, words, numbers, and colors.

Here's an example in Words mode, where it's reading off Quetzal and Robot.

alphabetical mode just does the letter.
Numbers mode makes the numbers keys say numbers, as you might expect. Colors mode just makes it read off the colors behind the numbers, instead.

and the music button plays music. it seems to be 4-5 MIDI public domain songs (the farmer in the dell, london bridge is falling down, etc) and a recording of the alphabet song.
Like so:

and the 4 emoji buttons play sound effects.
(and the home button is fake)

Anyway since you didn't come here for Cheap Baby Toys Explained, let's take it apart.
The back is pretty plain.
You've got a little speaker grille, a battery compartment, and a power switch.

The label says it was made in Dongguan, China.
And it's codenamed Walgreens-CNDG-0520

white on white is really hard to read, but that number seems to be 638749/ Smart Tablet.

The switch has three positions: ON, Try Me, and OFF.
A lot of these kids toys have a TRY ME/DEMO mode so they can be active in-store, but in a low-power mode where they won't drain the batteries as fast.

Those batteries, btw, are two AAA cells from GoldenPower.

Let's open it up.
It's very minimal! You've got two PCBs: one for the switch, one for the Smarts, a speaker, a battery compartment, and a ribbon cable off to the front panel.

The speaker is tiny and unlabeled, other than an M.
apparently it puts out M watts.

The PCB for the switch is suspicious.
So the switch has 3 positions, right? but there's only two wires coming off it and going to the main PCB.
Presumably that unpopulated A9 pad would trigger the demo mode... but since it's not there, it's just regular-on when in demo mode

That PCB says XL16739A (no results), 200421 (21th week of 2004?), 0296, and 1.4HB.

And it's a big blob. BOOOOOO

There does seem to be a trace for the A0 connector, which I assume is for DEMO. I wonder if it acts differently if I short that to ground (or power? I'm not sure which it needs)

There's also a "V" pad that's unpopulated.

Nothing on the back of the board, except a sharpie squiggle.

So while attaching to those flex connectors is annoying, this board actually makes it potentially really easy for me.
See those holes above the contacts? I could just solder on a header there, and attach to that.

Although I'd need to cut all the traces to the blobbed IC to keep it interfering with my HAX

but before I go attacking the board, lemme try hooking up the demo connector and see how it works

I would show you how the keyboard works, but I know, and it's annoying.
It's a simple membrane keyboard but it's the annoying kind where it's held together by a big sticker.
so you can't reverse engineer it directly without destroying it

so you gotta do it blind from the flex connector.
which is annoying, but possible

ok, according to my multimeter, when the demo mode is on, the A9/A0 pin is shorted to V+

And now thanks to some quick shitty soldering, it is reconnected. let's see what, if anything, is different!

OK, as far as I can tell, nothing is different.
So presumably it's just an input to the processor which they're ignoring, but other firmwares might listen to it.

trace-cutting time.

I would just snap the PCB in half and only use the half I need, but cutting PCBs consistently is hard with the tools I have on hand, and also having the full PCB there helps with stability.

Traces are no more. I sliced it with a knife, then doublechecked with a multimeter that there was no continuity

Dang it, those bastards used a 2.5mm pitch instead of the standard 2.51mm

I don't have any matching connectors (or any 2.5mm to 2.51mm cables) so I'm just gonna have to solder 15 wires manually, like some kind of caveman

rainbows are all that can save me now

OK there. attached.
It took forever and it's a mess (that's why I censored it, so I wouldn't get 900 replies of "YOU CAN'T SOLDER")
I think they may have messed up the solder mask on some of these, they just didn't want to solder. I should have wire-brushed it before soldering

now I just need a Teensy and to figure out the matrix.

A teensy (specifically, a 3.2) has been attached. TO THE CODE!

I'm trying to be smart and not have to be dumb while mapping out the matrix. it's not working

there's also some weird code problem. I'm reusing existing code, but when I build my matrix-scanner code and it tells me that 1-14 is key "1", I then plug that into my keyboard code and it refuses to register it as a keypress.
why? I have no idea.

unless they put diodes in this keyboard, which is laughably impossible.

at this point it probably would have been simpler and faster and cheaper to have bought two of them and planned to destroy one to figure out the matrix

arg, it's partially a hardware problem too. some of those unsolderable bits have disconnected

I ran out of time to hack on it, so I gave up and yanked off the sticker.
Here's the matrix!

I didn't expect it to have a label on it.
XXD, 9055X?

it's hard to tell from that picture but if you look close you can see there are two different layers, which have slightly different colors.

I think park of the issue is that it has a really high resistance, which I think might have been messing up the sensing

Man I might have been a little slower to tear up my tablet to map the matrix if I'd known IT WAS THE LAST ONE.

Silver lining though... Hello there.

Fortunately I'm lucky enough to have two Walgreens within like a mile or two.
Unfortunately the second Walgreens doesn't have it either.

Wait, what year is it?

BTW, regarding that My First Games Controller:
It's probably not the one you're thinking of, which is this one, the Fisher-Price Game & Learn Controller. https://twitter.com/Foone/status/1025237809475411968

but apparently someone thought it was a good idea to clone it.

I think I need a better microscope.
This is the best image I've gotten of the die

floppy for scale

A slightly better picture

I've got another microscope somewhere but I'm not sure where it went

I need a macroscope to find it

I had an idea of where it might be, so I checked, and it wasn't there, but there was a VHS tape.
A VHS tape? that's odd, I wonder what that is?

Oh. God damn it.

9 tracks, but it starts with the obvious one.

BTW this isn't the only time I've rickrolled myself: https://twitter.com/Foone/status/1049747210756182017

by far: https://twitter.com/Foone/status/1229870983021912066

it really, really isn't: https://twitter.com/Foone/status/1165851300908527617

and it's a minor form of it but I did order a copy of the song on cassette tape and then forgot I ordered it https://twitter.com/Foone/status/1011400366267629568