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Priv-like Android device building

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Kyle M.

Senior Member
Feb 2, 2015
77
5
Hamburg
Hi everyone,
I own a Priv and can't do without a keyboard. Seeing that (as of today) no new portrait slider has been announced, and modding the motherboard itself is unrealisitic, I've decided to find a motherboard and screen off a newer phone and sort-of slap them on a spare chassis I've got lying around.

Feel free to add suggestions and comments below, I need all the expertise I can get. Hit the like button if you're interested, so i can get a head-count. If you guys and gals are interested, I'll post pics as I go along.
 

Kyle M.

Senior Member
Feb 2, 2015
77
5
Hamburg
Keyboard & Interface:

In an ideal world, I'd be using the priv's existing (and exquisite) PKB which also has touch capabilities for scrolling and moving the cursor. Unfortunately I've not yet found the pinouts for that (and is more complex to interface). I have however found a website where a good soul published info and diagrams for a Q10's Keyboard and then connected those to an IC using a board with a Hirose connector (which he then connected to a raspberry pi project). My plan is similar. Since I don't know at which point in the motherboard I can make an input for a keyboard, the best strategy is to wire the keyboard's interface chip into the USB connections, as Android natively supports USB keyboards and mice. I can then use a microswitch (mechanical or magnetic) to disconnect the keyboard's signal when the slider closes.

If someone does know the pinouts of the Priv's connector, do let me know, it would be great to be able to use it!
 
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Kyle M.

Senior Member
Feb 2, 2015
77
5
Hamburg
Motherboard & Screen:

First thing that springs to mind, is that since the screen will be sliding a couple of inches, the phone off which I'll take the screen and motherboard needs to have a long flex-ribbon, usually found when a motherboard is on the top, and the screen connects on the bottom (such as the oneplus 5). This also means the charging port would also be nice to be a separate unit. I'm not too worried about cooling as there's a nice big metal slider frame to which all this will stick on, but failing that, i could also make a metal back with shallow fins to dissipate heat. The less features there are directly on the screen, the less things are likely to fail.
 
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Kyle M.

Senior Member
Feb 2, 2015
77
5
Hamburg
Requirements:
So the basic point of all this is to have the keyboard hooked up to the motherboard of a rootable system which can be easily modified. Phones like Xiaomi, Oneplus ... fit this bill well. First thing that springs to mind is a Snapdragon 8xx as performance is of course, vital. The camera also needs to work although the resolution is not critical. NFC, Fingerprint sensor, SD card slot, GPS with Galileo, Wireless charging and other niceities are highly desireable, but I might give some of them up to accomodate other things depending on how critical they are. Unfortunately not many flagships have 5.4" screens or less, so the metal slider will be modified to accomodate this.
I'll choose a nice, big battery and place it in the bottom, right below the keyboard as the CoG needs to be really low to make the phone comfy to type on without letting it tip over.
Finally, a plastic or metal cover can be modelled to fit all this, and will probably be cheap to make. If the screen is bigger than the frame, i'll also have to make a second cover around the border, secured to the main slider frame.
 
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Kyle M.

Senior Member
Feb 2, 2015
77
5
Hamburg
The Q10's keyboard has arrived. The connector seen in the middle with a black ribbon has 24 contacts (plus 4 contacts in the extremities which are not counted, probably used for grounding). By comparison, the Priv connectors (male on top, female on motherboard) has 20 contacts despite the priv's trackpad function.

For those of you curious about the BB Passport, I've had a quick look inside and the connector is identical to the Q10's keyboard, although it works like the Priv. Rather confusing.

I'll be mapping the pinouts once the PCB and connectors arrive, unfortunately that's gonna be a long wait as they have to come to Germany from the U.S.
 

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Kyle M.

Senior Member
Feb 2, 2015
77
5
Hamburg
I finally have enough parts to start putting the encoder together. It is an SK5126 keyboard encoder from Sprintek. At just 7 x 7mm with 0.5mm pitch, it was not easy to solder on, but definitely doable with a bit of practice and common sense. The chip itself is not expensive (15usd a pop) but being in Germany, I had to pay through the nose for shipping and shameless customs. Sprintek's sales dept. have been very helpful though. Once I wired the PCB to an old USB cable (and a couple of resistors & capacitors), it was very much plug & play. I'm pleased.

Now it's time to wait again for the next bit of PCB and female connectors for the keyboards... It's at times like these that I regret the EU not having a trade agreement with the US.
 

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Kyle M.

Senior Member
Feb 2, 2015
77
5
Hamburg
The adapter PCB and Hirose female connector for the keyboard finally arrived today, but that's where the good news ends. Unfortunately the seller did not solder them together so I had to do it myself. That's when an obvious fact hit me in the face: the connector's melting point is lower than the solder paste's melting point. The first connector simply folded in a mess of molten plastic under the hot air. I tried the reballing method on the second (and last) connector, which simply pulled the individual legs of the connector apart.

Upon putting the PCB of the Encoder and the connector next to each other, it's clear that part of the success i had with soldering the encoder chip lied in having a footprint with nice long exposed contacts which allowed the surface tension of the solder to pull everything in place. That could not work on the much shorter footprint of the connector PCV. I've ordered some more connectors, it's gonna be a long wait, though I've yet to think of a proper way to solder without melting the connector.
 

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Kyle M.

Senior Member
Feb 2, 2015
77
5
Hamburg
So I've finally had a breakthrough. Some new PCBs arrived from Hong Kong and after a few molten connectors, I've managed to perfect the technique enough to not get any shorts. From there on, it was pretty straightforward. I mapped the keyboard's pinouts (red pcb) to the correct Row/Coloumn inputs of the encoder (green pcb) using the thin wires. It looks a bit messy until i figure out in which position the PCBs will sit inside the chassis.

I'm tempted to also try mapping the Priv's original keyboard, unfortunately, that's tricky, as there's no info about it online. It has a 20-pin connector (as opposed to 24 on the Q10) which also transmits touch input via a Synaptics microchip. I'll try going through it with a multimeter, if i can at least map out the button-matrix, then finding out the synaptics output will be a tad easier.

In the meantime, another issue is on my mind. I've been looking at teardowns of various snapdragon 7xx and 8xx phones and it's clear that some components (mostly the prox sensors) on most, if not all models, are soldered directly on the motherboard, which makes it difficult if I plan on putting the screen on the sliding portion of the chassis and the motherboard on the fixed portion of the chassis. I'm going to have to rethink the whole idea. If i put a lot of components on the sliding part of the chassis, then i risk making the phone top-heavy and thick. Unfortunately I do not have the technology to change this.

There is probably going to be a compromise somewhere, and I need to decide where to draw that line before I order more expensive parts.
 

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elchmartin

Senior Member
Oct 17, 2014
170
51
Duesseldorf
Google Nexus 4
Nexus 7
very (!) interesting idea(-s) !!
I am incredibly curious to see the outcome, afraid I cannot really provide any help.

it is a real shame that blackberry didnt even provide some use-at-your-own-risk stuff to boot unsigned code...

maybe you want to try shopping for parts in china directly, I almost never pay customs (value below ~€20) for stuff.

cheers!
 
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Reactions: Kyle M.

Kyle M.

Senior Member
Feb 2, 2015
77
5
Hamburg
very (!) interesting idea(-s) !!
I am incredibly curious to see the outcome, afraid I cannot really provide any help.

it is a real shame that blackberry didnt even provide some use-at-your-own-risk stuff to boot unsigned code...

maybe you want to try shopping for parts in china directly, I almost never pay customs (value below ~€20) for stuff.

cheers!
Thanks mate.

I already buy a lot of parts from China, however 1 thing I couldn't find online from there was an easy-to-use, low power encoder. I had to get it from Sprintek in California. Their products are really good and the price is also good. Unfortunately i had to pay a lot of money for customs (which of course is not Sprintek's fault). The encoder chips themselves cost me around $15 each, the programming software is free and the chip responds right away as soon as you plug it into the pc. They also have a good after-sale assistance.
 

elchmartin

Senior Member
Oct 17, 2014
170
51
Duesseldorf
Google Nexus 4
Nexus 7
Thanks mate.

I already buy a lot of parts from China, however 1 thing I couldn't find online from there was an easy-to-use, low power encoder. I had to get it from Sprintek in California. Their products are really good and the price is also good. Unfortunately i had to pay a lot of money for customs (which of course is not Sprintek's fault). The encoder chips themselves cost me around $15 each, the programming software is free and the chip responds right away as soon as you plug it into the pc. They also have a good after-sale assistance.

You are living in Hamburg, Germany?
Maybe try looking for parts at pollin.de
They served rather rare items for me some times...
 
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Kyle M.

Senior Member
Feb 2, 2015
77
5
Hamburg
I can finally update with some good news. After ironing out all the issues (most of which concern the pesky Hirose connector which connects the keyboard to the PCB), I took the 2 boards off the metal frame and made myself a little box from PVC sheets which I then glued to an old Xiaomi phone cover. The reason I am testing it this way rather than just building the slider I wanted to build is to prevent having to mod the Xiaomi phone while testing (I've grown quite attached to this phone despite having bought it cheap).
I have also put a small switch on the side which directly cuts off the power to the chip (this way it saves power and seems to work pretty fine).
 

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    very (!) interesting idea(-s) !!
    I am incredibly curious to see the outcome, afraid I cannot really provide any help.

    it is a real shame that blackberry didnt even provide some use-at-your-own-risk stuff to boot unsigned code...

    maybe you want to try shopping for parts in china directly, I almost never pay customs (value below ~€20) for stuff.

    cheers!
    1
    Thanks mate.

    I already buy a lot of parts from China, however 1 thing I couldn't find online from there was an easy-to-use, low power encoder. I had to get it from Sprintek in California. Their products are really good and the price is also good. Unfortunately i had to pay a lot of money for customs (which of course is not Sprintek's fault). The encoder chips themselves cost me around $15 each, the programming software is free and the chip responds right away as soon as you plug it into the pc. They also have a good after-sale assistance.

    You are living in Hamburg, Germany?
    Maybe try looking for parts at pollin.de
    They served rather rare items for me some times...
    1
    I can finally update with some good news. After ironing out all the issues (most of which concern the pesky Hirose connector which connects the keyboard to the PCB), I took the 2 boards off the metal frame and made myself a little box from PVC sheets which I then glued to an old Xiaomi phone cover. The reason I am testing it this way rather than just building the slider I wanted to build is to prevent having to mod the Xiaomi phone while testing (I've grown quite attached to this phone despite having bought it cheap).
    I have also put a small switch on the side which directly cuts off the power to the chip (this way it saves power and seems to work pretty fine).