1-by-One Folding Bluetooth Keyboard: Flex Cable Fix

Four years ago I got a folding Bluetooth keyboard for my then-newish Pixel phone:

Folding keyboard - front
Folding keyboard – front

A few days ago, the 2 W S X Win keys stopped working, suggesting a problem with the matrix scan of that column.

The trim cover over the fold on the back of the keyboard disengages from the hinge with gentle prying at the obvious places, exposing a flex cable pressed against a disturbingly right-angled edge:

Folding keyboard - acute cable fold edge
Folding keyboard – acute cable fold edge

Unfolding the keyboard makes the acute bend against the case obvious, even though it’s hidden under the cable:

Folding keyboard - failed cable - borrom view
Folding keyboard – failed cable – borrom view

Some tedious poking around with a continuity meter revealed not only a broken trace, but a crack in the flex cable:

Folding keyboard - cracked flex conductor
Folding keyboard – cracked flex conductor

Protip: when you have nothing to lose, poke a pin through the flex cable into the trace to localize the break. The point leaves little holes, but so what?

I scraped off the black coating and the insulation over the traces with an Xacto knife under the microscope, which definitely reveals my need for a tiny Waldo manipulator.

Coating the exposed copper with solder and bridging the crack with one strand of the finest wire in my collection produced a truly horrific scene:

Folding keyboard - patched flex conductors
Folding keyboard – patched flex conductors

The glop on the left is flux applied before soldering. The rugged terrain on the right is the exceedingly gummy adhesive holding the cable to the keyboard, which turned out to be surprisingly heat-sensitive.

Fairly obviously, those patches will not survive much more flexing, so wrap the cable with Kapton tape and apply a stiffening layer of thick plastic tape:

Folding keyboard - reinforced cable section
Folding keyboard – reinforced cable section

Apply more reinforcing tape and button it up again:

Folding keyboard - reinforced cable flex edge
Folding keyboard – reinforced cable flex edge

I stuck the flex cable down with the repaired joint about a millimeter under that sharp edge, with double-sided sticky tape underneath to help immobilize the bruised area.

While I had the covers off, I also reinforced the same section of the cable on the other side of the keyboard, in the hopes of preventing a crack.

I have little faith in the long-term survival of this repair. Similar keyboards routinely emerge from the quantum froth of randomly named Amazon sellers, most of which have negative reviews reporting the failure of entire key columns; there’s no indication of any design improvement.

The alert reader will have noted the cable has eight traces, enough for a 3×5 matrix of 15 keys, but the folding wing has 16 keys: the second row has four keys. I have no idea how they made that work, other than perhaps resistive coding for some of the keys.

Google Play Store Ad Bidding Delay

Being that type of guy, I turn my phone off during the night while it’s charging, turn it on for the next day’s adventures, and check the Google Play App Store to see which apps will get updates.

The vast machine learning / AI / whatever analyzing my every move still hasn’t figured out my morning ritual, so it desperately tries to sell me crap:

Google Play Store - app ad delay
Google Play Store – app ad delay

My guess: those blank spots are placeholders for app ads, but, while the phone is busy scanning for malicious apps, the ad bidding process doesn’t complete fast enough to update the display before I see it.

FWIW, I had the Genuine NYS Covid-19 app installed for a while, but I very rarely go anywhere or see anybody, so it seemed to offer no net benefit.

Stylus Tip Restaking

The tip of the much-battered stylus useful for websites presenting tiny phone-hostile buttons appeared in the laundry basket, narrowly avoiding a trip through the washer. The shell’s original all-around swaging had evidently loosened enough to release the tip, so I applied a hammer and punch:

Screen stylus tip restaking
Screen stylus tip restaking

The punch mark (with another on the opposite side) is barely visible, but holds the tip securely in place. Next time I may need more hammer.

Huion H610Pro (V2) Tablet vs. USB 3.0

For reasons that surely made sense at the time, the Huion H610Pro (V2) tablet can recognize when it’s connected to an Android device’s USB port and enter a special mode where the stylus only responds in a phone-shaped portrait rectangle over on the left side:

Huion H610Pro (V2) Tablet - Android layout
Huion H610Pro (V2) Tablet – Android layout

There’s a Vulcan Nerve Pinch button push to force the tablet into Android mode if it doesn’t automagically get there on its own, but AFAICT there’s no way to force it out of Android mode.

It’s a USB 2.0 device, but I had plugged it into a USB 3.0 port on my desktop box, whereupon it would enter Android mode on pretty nearly every boot. The only way to coerce it back into normal mode was to unplug it, replug it, then manually run the xsetwacom incantation to restrict the coordinates to the portrait monitor.

I just discovered it works perfectly when plugged into one of the few USB 2.0 ports on the box.

Apparently, USB 3.0 ports keep the thing powered all the time, whereupon it doesn’t see the proper sequence of events (or, perhaps, sees the Android sequence) during the next boot. USB 2.0 ports don’t do that and it works fine all the time.

Much better!

Pixel 3a Screen Protector FTW!

Despite carrying a glass-fronted gadget in my pocket for most of the past two decades, this is the first time I’ve done this:

Pixel 3a screen protector - as broken
Pixel 3a screen protector – as broken

Turns out you can’t trust a rolling seat on a slightly unlevel surface, as shifting your weight can let the thing roll out from under you with no warning. If you’re taking a picture at the same time, the phone reaches the impact point before your hand: even a nice case with bumpers all around won’t be quite enough protection.

I was tempted to leave it un-fixed as a constant reminder to not do that again, but the broken glass was rough to the touch and interfered with Android’s swipe-upward gestures.

Fortunately, the tempered-glass screen protector absorbed the energy without damage to the actual screen:

Pixel 3a screen protector - sidelit
Pixel 3a screen protector – sidelit

A thin plastic layer holds the protector’s fragments together; I hadn’t known it was a two-layer structure.

Being that type of guy, I had a spare protector in a desk drawer and managed to apply it without trapping any bubbles or fuzz underneath.

Finding & Copying Only The New Music Files

Given a collection of music files in various subdirectories, find all the mp3 files that aren’t in the target directory and copy them. The only catch: don’t use rsync, because the target directory is on a Google Pixel phone filesystem which doesn’t support various attributes required by rsync.

The solution goes like this:

cd /mnt/music/Netlabel Mixes
sudo jmtpfs /mnt/pixel -o allow_other,fsname="Pixel"
find . -name \*mp3 -execdir test ! -e  /mnt/pixel/Internal\ shared\ storage/Music/Netlabel/\{\} \; -execdir cp -v -t /mnt/pixel/Internal\ shared\ storage/Music/Netlabel/ \{\} \;
sudo umount /mnt/pixel

The trick is remembering the second execdir operation in find happens only if the first succeeds, so the cp runs when the target file doesn’t exist.

All the backslash escaping gets tedious, but it’s the least awful way to get the job done when the directories contain blanks, which is true for the default directory structure inside the Pixel.

Your choice in music will surely be different …