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Messages - mifritscher

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Cosmo Communicator - Hardware / Re: New Batteries Anywhere? (Shipped to USA)
« on: September 23, 2023, 10:37:26 am »
I went a similar route - details at :-)

My cosmo had a inflated battery as well. I searched for a third batttery which fits into the cosmo (soldering is fine for me), but the biggest problem was the required thinness of the battery (original name: SXX600, original size: 13.6 x 6.2 x 0.3 cm, original capacity: 4220 mAh)

Eventually, I stumbled over, which is  9.0 x 6.0 x 0,3 cm and has 3000mAh. The size is almost perfect - 2 dimensions are fitting completely, the other being about 4 cm less. Which is actually rather good, because this way I have some space for the cable. soldering etc.

Both batteries - the old and the new - have a tiny pcb with 2 (dual) mosfets and a tiny controller. On the original pcb, there is not only P+/P- on the connector, but also an ID and a "Test" line (is written on the connector cable). I used both PCBs - the old one for satisfying the id+test lines, the new for a additional safety layer. And because it was the easiest way :-D

My biggest fear was that the pcb locks itself if there is no voltage anymore on the battery cell side as a safety measure (quite common on laptop batteries). To avoid that, you have 2 choices: temporary connect an external power supply ( 4,4V, 100...200 mA will do), or connect the old and new battery in parallel. I went the second way, which is easier, but needs a bit of preparation.

The main problem is to prevent a high current at the moment of connecting the both batteries.

Luckily, my old battery had already a quite big impedance because of its defect. If you have a power supply with adjustable voltage and current (or a current limit of max. about 2A): Measure the voltage of the battery (in my case: 2.9V) Then apply a voltage of 0.1 V (max. 4.4V) more than that. If the current is less than about 1 A (typically: _much_ less, 50 mA is a typical value): Go up to 4.4V (or, if you have already the new battery: 0.1V more than that, should be about 3,7... 4.2V, mine had 3,9V). If the current stays under 1 A the old battery is either full or has an high impedance. Both is good.

If the old battery has an _higher_ voltage: discharge it until the voltage is a bit under the new battery.

The old cell was connected to its PCB via contact welding the connectors. Luckily, soldering right on the connectors works fine. So I soldered first the black wire of the new battery on the old PCB (mind the polarity, there is also a "B-" on the PCB). Then I hold the red wire on the B+ connector on the old PCB. No smoke ( :-D ), so I soldered the red wire on it as well. Then I disconnected the alu connector of the old cell with a scissor (please do not short anyshing :-) ). Then I isolated everything, taped it with duad side tabe and screw everything together again.

1. Cosmo started, displaying a SoC of 64% and 3.9V
2. It charged fine and linearly up to 100%
3. It discharged fine and linearly up to 0%, lasted the predicted time (about 11 hours with quite a load - hint: disabling the cover connection with the app and the cover in the "quick selection" area helps ;-) )
4. It chaged finde and linearly up to 100% again, with an internal measured (with AIDA64) energy of 2946 mAh - perfect strike :-)



P.S. This should work on the gemini as well.

Cosmo Communicator - Hardware / Solution for sometimes not detecting the SIM
« on: September 23, 2023, 10:24:58 am »
Sometimes, the SIM is not detected. You see the problem here: 

The carrier shorts the contact fields of the SIM. Solution: Tape :-D

One (little) feature request: As the system already uses ext4 for internal partition, please allow the usage of ext4 partitions in the "shared medium" variant of the sd-card as well. exfat would be even better ;-) Currently, only fat32 is permitted, which can't handle files bigger than 4 GB, which is a problem for e.g. offline wikipedias. Android wants to format sdcard with any other file system.

I know that there are unofficial ways for rooted Android, but this would be a nice (and probably easy) feature for the "normal" Android.

I rooted my cosmo the "official" way, ie installed the rooted kernel in one of the slots (should be EMPTY_NORMAL_BOOT_3 or EMPTY_NORMAL_BOOT_4). The problem is that the SIM card is only detected in normal (non-rooted) android, not in the rooted version.

Can it be that lk does initialize the modem only when booting from the normal android boot partition?

Quote from: cam1965
Quote from: mifritscher
Hmm, for me it is working... Despite having problems unlocking the user partition (I didn't activated the encryption...)

Did you install twrp from the zip file ( link above ) ?

Yep, I used the one at . Note that it shows the TWRP logo for 1-2 minutes before giving up on decrypt the user partition. And I repartitioned the system before (60/60).

Hmm, for me it is working... Despite having problems unlocking the user partition (I didn't activated the encryption...)

Just change the 5th bytes onwards from the 00  to your current mac (use e.g. ifconfig for this), than press ctrl+c to save and exit.

Cosmo Communicator - Hardware / Serial Console
« on: November 29, 2019, 04:15:11 am »
Wasn't this more a built-in feature of the geminis SoC + the bootloader?

Additionally, I think the microcontroller of the cover display is connected with something simple - straight uart, i2c or spi. This could be used for debugging as well

P.S. The forum server throws a lot of http 500...

Cosmo Communicator - Hardware / USB-C
« on: March 13, 2019, 07:58:21 pm »
At least for me, also the right side of the Gemini supports the hub.

Gemini PDA - Linux / Mainline linux kernel
« on: August 13, 2018, 02:01:57 am »
hmm, 4.19 seems to have a lot of cool stuff for x20 /mt 6797

Gemini PDA - General Discussion / 4G Gemini as main device ?
« on: August 13, 2018, 01:57:16 am »
I use it as my main phone - and also as main laptop for the "little" things

Gemini PDA - General Discussion / Games on Gemini
« on: August 13, 2018, 01:52:23 am »
Manaplus (free and open source MMORG) works fine

Gemini PDA - Hardware / Supplied charger supports MTK Pump Express
« on: July 01, 2018, 04:34:19 am »
I measured it some time ago - there are going 1,5A by 5V over the USB cable. Which are 7.5W - which is ok I think.

Gemini PDA - Hardware / Displaylink adapter works (under Android)!
« on: July 01, 2018, 04:28:31 am »
I tried a (random dual output USB 3.0 which I bought several years ago) Displaylink adapter on the right side. And it worked flawlessly after installing the Displaylink app :-) Only problem is that in OpenGL ES apps the external display doesn't work (Tested with supertuxkart).
It even works in combination with the Gemini Hub and without a external power supply.

So there is finally a way to have power, USB and external display at the same time :-)

I'll add the type of the adapter tomorrow when I have access to it again.

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