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Messages - zevv

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Gemini PDA - Hardware / A year with the Gemini
« on: April 14, 2019, 01:23:04 pm »
So, has it been a year already? The day I put the Gemini in my pocket, I felt as if it had always been there - we made for a perfect match from the start. I have been carrying and using the Gemini for 365 days now - a good reason to make a little writeup of my experiences.


Not much to tell here. On arrival I installed Termux, Firefox and K9, which make up about 90% of my interactive use with the Gemini. I never enabled any google accounts or services, and not having access to Play store nicely keeps me from installing too much cruft. I was bothered to hell though, by the keyboard ghosting and speakers being out of phase - luckily I know how to build a kernel, so I made some hacks and workarounds to fix that, and I never updated the kernel since.


This is the interesting part, in my humble opinion. My first impression of the build quality was "fair" to "ok", but I was not convinced the device was up to the task to travel in my trouser's pocket day after day. It has now stood the test of time pretty well.

The year was not without accidents, including - but not limited to:
  • Me bumping into a table or door handle, the Gemini taking the hit. Repeatedly.
  • A straight 1.25m drop from my hands onto concrete. Once.
  • Sitting on the Gemini (closed). Daily.
  • Sitting on the Gemini  (opened!), in a soft couch. Once.
  • Elliptical curve from my pocket onto the pavement when getting out of my car. Three times. This is mainly due to my favorite pants having crappy pockets.
  • Sand. Aaargh! Sand. Sand is bad for the gemini. Very bad. The keyboard is not. at. all. able to handle any sand. If a single grain of sand gets stuck in the sliding part of a key, it is game over for the day, and canceling evening plans to spend a few hours on the kitchen table: popping the keys, cleaning with canned air, and putting it all back together. This happened twice. I wonder why I even considered taking it with me to the beach the second time.
Here are some honest and uncensored pictures of the current state of my device.

The dust is always there, it just collects in my pockets and gets into the Gemini. It doesn't seem to care, though:

[img]\" border=\"0\" class=\"linked-image\" /]

Some bumps and scratches do build character, and these are scars to be proud of:

[img]\" border=\"0\" class=\"linked-image\" /]

And one day I noticed this: the hinges seem to be cracked on both sides. I'm not sure when this happened, but my guess is there might be correlation with me sitting on the Gemini when it is open. Everything still works as before though, so no problem at all:

[img]\" border=\"0\" class=\"linked-image\" /]

So, it has been a good first year, and I truly do hope the Gemini will keep up for a few more years. I'm not sure if I'll even consider Planet's next product - the backlight would be nice, but it the keyboard quality is not significantly better, I'll stick to my Good Ole Gemini.

Thank you Planet, a job well done!

Gemini PDA - Hardware / Keyboard ghosting
« on: September 06, 2018, 09:18:13 am »
I just flashed this boot image and it works great. The ghosting is gone. Thanks a million!
Would you be willing to link to a description of how you rolled this kernel into a new boot image?

It's in the readme of my repo:, check the section 'Building'

Gemini PDA - Hardware / speakers out of phase?
« on: August 27, 2018, 08:45:22 am »
Quote from: speculatrix
cool! does it flip the phase only on speaker?

Yes, it peeks into the accessory state and only fixes the phase when no headset is attached.

Gemini PDA - Hardware / speakers out of phase?
« on: August 26, 2018, 06:47:51 am »
Quote from: speculatrix
given it's possible to build, and indeed people have, kernels for Debian, do you think we can at least have sound fixed when running linux and not using the Planet-built kernel?

Here is an Android kernel:

This is a build of the stock Gemini kernel from Planet with two fixes: audio phase and keyboard ghosting. You could ask the Gemini maintainers if they are willing to pull in the speaker fix patch into the Debian kernel as well?

I've been running this for about a month without problems.

Gemini PDA - Hardware / Teardown?
« on: August 18, 2018, 02:49:33 pm »
Not much of a teardown, but this is below the black plastic cover panel:

[img]\" border=\"0\" class=\"linked-image\" /]

[img]\" border=\"0\" class=\"linked-image\" /]

[img]\" border=\"0\" class=\"linked-image\" /]

(Edit: I realized I just posted my IMEI barcode - very smart. Image edited to white out)

Gemini PDA - Android / There IS a useful AGENDA app for the Gemini
« on: July 29, 2018, 11:37:28 am »
Quote from: gidds
The next hurdle is: do I need to sign into Google to buy it…?

No, you don't. I contact the developer by e-mail and was able to pay using paypal, after which I received a link to the .apk to download and manually install.

Gemini PDA - Android / There IS a useful AGENDA app for the Gemini
« on: July 29, 2018, 02:53:34 am »
Quote from: gidds
Does CalenGoo need you to sign into a Google account, like the Planet Agenda does?

No, it does not. It allows you to sync to any android calender - which for many people means syncing to google - but it does not in any way depend on google services.

I run Calengoo together with DAVdroid [1], and sync to a Radicale [2] server on a linux box - no google involved here.

Gemini PDA - Android / Firefox
« on: July 28, 2018, 04:56:53 pm »
This one might be a bit too extreme for your regular user, but I'm a big fan of the Tridactyl add-on:

 "Replace Firefox's control mechanism with one modelled on VIM."

I have been using this (and "vimperator "before) on desktop for a long time, and in a bold mood also installed this on the Gemini - and now can control 99% of the browser by keyboard.

Gemini PDA - Android / PgUp and PgDn not working
« on: July 24, 2018, 12:49:26 pm »
I just fixed this in Termux and submitted a pull request to upstream. Now we wait.

For the impatient, the brave and the testers, here is a debug build:

Gemini PDA - Android / PgUp / PgDn (Page Up / Page Down) not working?
« on: July 24, 2018, 12:47:39 pm »
I just fixed this in Termux and submitted a pull request to upstream. Now we wait.

For the impatient, the brave and the testers, here is a debug build:

Gemini PDA - Hardware / Keyboard ghosting
« on: July 20, 2018, 11:31:34 am »
Quote from: Murple2
Thanks that's really awesome. Can you post a link to Nathan Banks' code, or explain the fix?

Of course, here is his original pull request on Gemian (which has not been merged yet):

The Gemini PDA keyboard has 2-key roll-over. That means that if 3 or more keys are pressed down in some combinations, four keys will actually be detected. One example is that if K+J+D are pressed simultaneously, the old driver will produce K+J+S+D. Since I usually use the Dvorak layout, this meant that often if I typed "the" or "those" Gemini would produce "thoe" or "thoese" because I'm lazy about lifting up keys. It also meant that Control + L_Shift + M & N can't be differentiated from each other.

Instead of adding extra keys (ie. Ghosting) my changed driver now blocks the extra keys, however the keypress is registered if one of the first two keys is released before the third. Thus "the" in Dvorak is much easier to type, and Control+L_Shift+M will be recorded as long as the Shift or Control is released before the M. Unfortunately this is the best we can do without redesigning the keyboard matrix. I also changed the formatting to match the Linux Kernel.

See for a description of why keyboard Ghosting happens.

Gemini PDA - Hardware / Keyboard ghosting
« on: July 20, 2018, 07:33:27 am »
For the brave: I have created a Android boot image which has a fix for this issue.

You can find the image here:

Install with flashtool by downloading only the 'boot' partition and unticking the rest.

The original fix was made by Nathan Banks, I just took his code into the Android kernel source and built an image. It works fine for me, but use at your own risk, things might break.

Gemini PDA - Hardware / speakers out of phase?
« on: July 19, 2018, 03:32:44 pm »
No, still mono. It seems that at the driver and alsa level the device is perfectly capable of playing stereo sound. Both left and right channels are mixed to mono.

In logcat there are some messages coming up when switching from headphones to speaker indicating this is a deliberate action:

07-19 20:27:16.946   482   838 D AudioFlinger_Threads: SetStereoToMonoFlag, mSteroToMono 1

This is a likely leftover from the original design the Gemini is based on which probably had a single speaker, in which case mixing to mono makes sense.

(Note the typo in there, it says 'Stero' instead of 'Stereo', likely this happens somewhere in propriatary MT code)

There is nothing I can do about this on the kernel level I'm afraid. I found some audio configuration in /system/etc/audio_policy_configuration.xml where the various audio channels are configured, but everything seems to be setup ok here. I'm not sure where to go from here, I have no experience at all going deeper into Android...

Gemini PDA - Hardware / speakers out of phase?
« on: July 19, 2018, 10:16:35 am »
Quote from: Anonymous_
zevv: does this mean L and R channels get separated with your fix? As before L channel has been played in both speakers as well as R channel.

No, it merely corrects the phase of the speakers.

I must admit that I was not aware that only the left channel was played. The fact that I'm able to flip the phase of one output indicates that the hardware is actually able to play stereo, so if only one channel ends up in the driver there must be a software issue somewhere down the line. I'll see if I can find some time to investigate.

Gemini PDA - Hardware / speakers out of phase?
« on: July 18, 2018, 03:47:34 am »
Quote from: Kiriririn
Awesome find! Can you share the source code of your change?

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