LAN connection without dongle on WM8650 tablet

When using a LAN connection with a tablet that hasn’t the RJ connector on-board, you can have some problem to gain the Heaven, ‘cause very often the “dongle” with the attached LAN cable detaches from the tablet, breaking all the connections (and probably your active work) and you, in such situation, may automatically start a sequence of @#@#@# and @@#@#@ that are not good to make points to your future “seat” up into the Sky.

So, what’s the simplest way to add an RJ connector to a tablet that hasn’t one ? It’s very simple : open the tablet and look for the transformer. Every tablet I’ve seen has all the circuitry inside, just the connector is outside, on the dongle. The transformer is the better place to solder wires, ‘cause has (usually) the pins spaced of 1.27 mm that is a measure easy to solder. In this picture, you can see one model of these transformers :

Even if your model is different, you will always have four small wires (look at the red arrows in the image) that comes from the “black bug” and go to the dongle’s socket. In my tablet’s specific case, the pins are named this way :

  • pin 16  RX + goes to RJ45 connector pin 6
  • pin 15  RX – goes to RJ45 connector pin 3
  • pin 10  TX + goes to RJ45 connector pin 8
  • pin  9   TX – goes to RJ45 connector pin 7

To clarify what are the positions of the pins on the RJ female connector / socket, here is a picture of the one that’s normally placed on the tablet’s dongle : note that the pin 1 is at the left ; the pinout suggested in the list above uses this standard.

Note that the pairs RX and TX are always “physically separated” (it’s a transformer !), so if in doubt when connecting a different type, consider that the TX and RX pairs are : one on a side, the other on the opposite. Also note that all the components on the circuit, needed for a correct ESD protection, are not mounted. It’s for sparing some money. In the practical use, if you just connect the tablet to a 1 meter cable tied to a router or another PC, you don’t need for it. Remember : you’re playing with very cheap devices. Anyway… soldering isn’t difficult, look here how I connected 4 wires of typical flat cable :

Not too difficult… and now, on the other side, I connected the RJ45 socket that will be used as tablet’s LAN connector. After testing the connection with success, use something like hot glue to make it “solid” and electrically insulated.

And finally, using a normal 1,5 meters LAN cable, I connected the tablet at my router and gained access to Google, as you can see in this final picture (note that wifi isn’t enabled !)

If you look a little bit deeply, you can see also other 2 cables coming out from the tablet… One is the serial port that actually is connected to IR led to work as remote control for my Sony TV, and the other is an USB female port, active and working (but unconnected in this picture), that I often use for my wireless KB / Mouse. Obviously… I hate tablet dongles 🙂

 

WM8650 tablet as remote control for Sony TV

Hello, here I am, again, with a simple mod for our tablets. In this picture you can see how it’s possible to control a TV set with our tablet using just one resistor and one IR Led ! In the picture you can see the tablet “dongle” (free of the plastic case) with the additional components needed. The circuit is the same proposed at point 3. of my article at this link (in Italian), just the led “color” is IR and the resistor is of lower value to gain some additional emitting “power”.

The IR led anode is directly connected to the 3.3V pad and the cathode to the resistor and this to the TXD pad ; the resistor value is 220 Ohm and must not be decreased in value.

Obviously, the distance you can reach with this small interface is very low, about 20 cm, but I will add in next days a driver circuit to make it working at longer distance. This is just a “proof of concept” (I like this definition).
At this link you can find the zipped APK file (the application) that I’ve written to test the device. Starting the application, you can see 12 buttons keyboard for entering the code to be transmitted, one “display” that shows what you type, and 2 other buttons: one is named “SEND” and simply transmits the IR code while you hold it down, and the other is named “QUIT”, to exit the application.

The program is compiled in debug mode, so without keys or locks. Deflate it from the downloaded zip and copy to sdcard of your tablet, then install it. Obviously, you must have the “unknown source” flag active.

The default command is 21 that in my Sony Bravia TV is the power-on / Power-off ; also test the numbers from 0 to 8 that are for changing channel from 1 to 9 ; for other commands, search on the internet for the Sony IR protocol.

Note: the program needs a small modification in init.rc file (you must be able to do this or the program will open with an exception error). In the init.rc command you MUST disable the console service.

this is the original:

## Daemon processes to be run by init.
##
#service console /bin/sh
service console /bin/login
    console

you must change it to :

## Daemon processes to be run by init.
##
#service console /bin/sh
#service console /bin/login
#    console

Obviously, this is a first try… so if there are errors, please, don’t shot me ! But give me your feedbacks and suggestions to improve it. Thanks

Home made tablet’s dongle

Yesterday I was in a supermarket for my normal needs for beer and chocolate (orange flavoured) and my attention was attracted by a big box with some “special offers” inside. It was full of old electronic devices like car chargers and wall power supply for cellphones. There was one for LG phones at 0.50 Euro ! I immediatly pick it up, thinking of use the 5V supply for some project or gadget of my own production.

When at home, I opened the plastic box (below you can see a picture of the label)

and cut the wire ; measuring the green and black wires my opinion was confirmed : 5.25V output and even if loading the wires with a low value resistor the power just decreased to 5.15V , so, now I have an efficient 5V wall power supply for 0,5 Euro.

But this isn’t the most important thing. Looking at the connector I just cut out from the wire (‘cause I don’t own an LG cellphone) I had a hearthbeat miss (just one eh)… the connector seemed VERY similar to the one (the 24 pin flat and small) that’s used in my tablet’s dongle (the one for expanding with 2 USB, LAN and pads for Serial Port). Look this picture:

Yes, is exactly the right connector ! Now, the problem is : for any normal use, I need at least for 4 pins, even for USB, even for LAN. In this days I’m using the LAN to connect my tablet to the PC to develop some applications, so will be VERY useful for me to have a supplemental dongle for my work. As you can see in the picture, the phone charger seems to have just 3 contacts, but isn’t true: the contacts are four ; the green wire is connected to 2 pins tied together as the black wire (but these pins are far and so more easy to see). Well, the 4 pins are placed, originally, in positions 4 and 5 for +5V (green wire) and 12 and 19 for GND (black wire). For my needs (the LAN connection) I must connect 7,8,10,12 pins, so only the 12 is at right place. The others must be moved. So you must extract, very carefully, from their original places and insert in the new ones. The pins are VERY small so you, probably will need for some “optical enhancement” ! After placing the pins in the right places, you can solder the wires, as shown in this picture :

After soldering the 4 wires, you can close the connector and use an appropriate LAN socket to do the rest of job. The final result will like as this :

The pinout for the connection is specific for the LAN. If you like to make a dongle, for example, useable for one USB keyboard, simply place the contacts in the positions of USB Vcc, D+, D- and GND (look at my Robotop’s Place on HcH / TK forum, in the section “Good quality schematics” and browse some tablet’s internals for the 24 pin connector pinout). Hope this will help someone to make his own tablet’s dongle, as I did. Please, note that most of tablets have a problem of thickness in the dongle insertion. The plastic thickness of the tablet’s border and the one of the dongle’s case, summed together, may give a unreliable electrical contact. The same is for this non-standard dongle. My solution, useful for both cases, was to reduce the tablet’s border thickness with generous use of a Dremel tool 🙂

Wireless mouse inside your tablet

Hello, I used old 7″ tablet (plus some circuit made by myself) as interface for house thermal control. The problem is that when I’m on the sofa and want to manual change some parameter, I must leave the sofa (and the cat) and go to the tablet, then press the buttons on touchscreen and change what I want. Now, I noticed that in this tablet there are 4 free pads for connection of USB camera. This tablet was developed for supporting dual camera, but in this arrangment there is only the CMOS one, so the USB isn’t used ; well, I decided to use the free USB pads to connect a wireless mouse !
Gone in a supermarket and purchased (expensive) 9,90 Euro wireless mouse. The miniaturized USB receiver is shown in the picture :

Wireless mouse USB receiver – new, never used

Ok : as first operation I removed the metallic chassis, to gain access to the contacts; the receiver now look as in this picture :

Oops, it has lost the metallic chassis 🙂

Now, I soldered the four wires necessary to connect to the tablet as you can see on next picture :

And now someone attached 4 wires…

Ok, now the last operation is to solder the wires to the main board. Look at the next picture :

Ok, wires connected to the pads (also 2 resistors have been added to mainboard)

OKAY, all right, turn on and… it doesn’t work 🙁

Ok, I have some schematic found on the Internet, so a quick look shown me that there are two missing resistors on CS: R141 and R144. The first one is just a jumper (0 Ohm resistor), while the second is a 100K resistor. I soldered both of them on the circuit and started again turning on…  et voilà, now it works  🙂

I have a wireless mouse inside my tablet. Now I can access my program by the sofa, ‘cause I used wide controls on the screen, for my application, and I can see them at (relatively) long distance…

Hope this will be useful for someone…

MIDI OUT for cheap tablets


midiout di robotop

Hello, I realized a really cheap and small MIDI OUT interface that can work with low-cost tablets (mine is based on WM8650 processor). Just for testing purposes, I also realized a Drum-Pad application that can play four different sounds if attached to standard Midi Expander. I used, in my test, a VERY old Roland SC-7 Expander with standard drum set. There are no problems to expand the number of pads ( until you fill the screen size ! ). At the moment I used only four as: Bass Drum, Snare Drum, Crash Cymbal and Open Hi-Hat. My circuit isn’t supported by ANY program, I have written the application using my own library and the supported MIDI commands are (actually) only NOTE ON, NOTE OFF and PROGRAM CHANGE. I probably will design a printed circuit board for making a “kit” for this device and also I’m planning to write some easy App to “play” with music. Obviously, at this first stage, this CAN’T be considered a professional tool, but can give some interesting opportunities to our low cost tablets.

Here is a picture of the device: (click to enlarge)

The program running…

 

I did it again: removable SPI flash II

Yes, I did it again… purchased a bricked tablet, can’t revive it in a “soft” way, so decided to make the SPI flash removable to rewrite it with the external programmer ( look at the previous version here ).


This time I used a normal DIL socket (8 pins) connected to the pads of original smd chip via 0.2mm enamelled copper wires. Obviously, that means now I need for a DIL 8 memory chip. I looked on the on-line Farnell catalog and found the AMIC A25L040-F chip with ordering code: 1907077 at less than 1 Euro per unit.
But “I can’t wait, I can’t wait, I will test the circuit immediatly”, so decided to adapt one small smd SOIC 8 memory chip on a standard 0.100″ DIL 8 socket to create a “Frankenstein” DIL 8 IC. Look at the results in the picture below… (click on images to enlarge)

The circuit (incredibly) worked and the tablet was revived. Yeah. A little problem, now… the tablet can’t close (mechanically) due to height of the 2 sockets stacked one over the other. Okay, this time I must wait for the right component, but in meantime I updated the tablet firmware with the UBEROID option 36 that worked after a little change in the command file wmt_scriptcmd. This tablet has 1024×768 screen and the script tried to open a 1024×600, locking the device. You can download my version of this script at this LINK (if interested to). Now, the specific IC is arrived and I executed a dump of the contents of working SPI flash (the “Frankenstein” one) on a bin file. After that, I programmed the new chip (the “normal” one) using that file as data source ; then mounted the DIL 8 chip into the socket, turn tablet on and… GO ! All working fine… Look below at the picture of new chip in the socket

Here is another picture (wide) of the board

Obviously, I modified the programmer’s circuit adding an 8 pin DIL socket to host the device under programming. Nothing difficult, just wired the pins to the correspondant signals of the existent SD card connector. Look on my other pages on this subject for additional infos.

My Android tablet has removable SPI flash

After two rom upgrades with wrong files, my tablet’s SPI flash was unable to run again a new upgrade, so I decided to create a removable SPI flash that can be reprogrammed externally. Now my tablet can’t be “bricked” anymore. If something wrong happens, I simply store a fresh copy of U-Boot and W-Load on the SPI flash and start again… (click on images to enlarge)


Well, I used a microSD adapter like this…

then, with small cutter I opened the adapter…

and soldered the small 8 pin SOIC spi-flash memory to the contacts, using 0.2mm enamelled wires.

After that, I closed the adapter using cyanoacrylate glue. The plastic over the memory was removed for making contact available for electrical inspection and thickness oversize.

Next step was to build a programmer using an SD card socket as connector. I used the same schematic you can find in my page here.

As final step, I soldered another SD card socket in the tablet, connecting the contacts to the pads of the removed IC with small 0.2mm enamelled wires. That’s all. After spi-flash reprogramming, the tablet started again looking for microSD card with the upgrade firmware.

A program to build the right SPI.BIN file for your tablet

I have had a bad experience in reprogramming the SPI flash of my tablet (a new one), due to wrong BIN file used (it was suited for ANOTHER tablet, with different RAM arrangement). After a couple of tries “in the blue”, I stopped working that way and decided to write my own software to merge the U-Boot.bin and the W-Load.bin that are in FirmwareInstall folder of specific update microSD, then create the right output BIN file to be used with external programmer for SPI flashing.

The SPI flash

SPI means Serial Peripheral Interface and “flash” is a particular type of memory, capable to be written (and rewritten) in fast mode and able to retain informations even if power supply is removed, so this kind of memory is part of the “non-volatile” devices.

What’s the purpose of SPI flash in our Android Tablet ? It’s like the (ancient) floppy disk in old computers. The floppy, in VERY old computers, was the device containing the Initial Program Loader, the first program the processor runs to start the whole system. In our tablets, the processor (I’m speaking about the WM8650, in this case) tries to load a boot program from this device. The SPI flash memory is small and simple device. Usually has 8 pins (contacts) and isn’t too miniaturized… it’s still at “human” dimensions and this is the reason we can remove it from the circuit, reprogram and resolder it on place. If your tablet is “bricked”, you can immediatly recover, simply restoring a valid boot program in it.
The hardware and the procedures for rewriting the SPI flash have been described in a very good article 🙂 by me on another page of my site, so, look around if interested in. But… what’s stored in the SPI flash of our tablet ?

There are two programs: the W-load and the U-Boot. The U-Boot can execute commands you supply via serial terminal or you have stored in the microSD, by means of the wmt_scriptcmd script file. U-Boot is the tool for handle the very low-level of your tablet. Btw, the NAND flash is another basic component of your system, ‘cause is your device’s HARD DISK. As in very old computers, the floppy loads the system skeleton and then the Hard Disk starts the programs with usual user interface (or GUI when is Graphical User Interface).

Ok, we turn ON the button, the processor starts, executes the program written in the W-load section. The U-boot then starts the system that’s on NAND memory and you have your tablet working.

When you try to unbrick your tablet rewriting the SPI flash, you must use the right version of U-Boot and W-Load, ‘cause if you choose a wrong version, all the process can’t start. A very important section (usually don’t mentioned) is the W-load program. There is a particular version for any RAM arrangment in your tablet. Not all the RAMs are the same: even if your “global” ram size is a certain number of MB, the rams can be arranged in different ways. For different arrangements, there are different W-loads.

How can I understand what’s my specific W-Load ?

You can take a look on the serial output that comes out from your tablet at power on. Obviously… you must do it before upgrading (and possibly bricking) your tablet ! The serial interface is a VERY powerful tool and I highly recommend to you to purchase (or build) one for modding and better understanding your tablet.
Look at this example :

WonderMedia Technologies, Inc.
W-Load Version : 0.15.00.01
UPDATE_ID_1_4_4_0_2_256MB_0150001
ethaddr............found
wloader finish

U-Boot 1.1.4 (Aug 24 2011 - 10:14:10)
WonderMedia Technologies, Inc.
U-Boot Version : UPDATEID_0.04.00.00.10
U-Boot code: 03F80000 -> 03FC3190  BSS: -> 03FCD724
boot from spi flash.
SF0: ManufID = 37, DeviceID = 3013 (Missing or Unknown FLASH)
Use Default - Total size = 8MB, Sector size = 64KB

There are some very useful infos: these are W-Load version and UPDATE_ID, U-Boot Version and UPDATEID. With such informations you can easily “build” your own SPI flash and it will be EXACTLY the one that fits your tablet. You also have infos on which type of SPI flash is mounted in the tablet. In the example before, the memory has ID 0x373013 (that is unknown to the system, so it starts with default values that are good for all memories).

How to build your BIN file for writing a new SPI flash.

Usually, the SPI flash has 512KB (kilobytes) space, but if you look on the datasheet it’s called a 4 megabit memory; that’s exactly the same, ‘cause 4Mbits = 512KBytes.
In our tablets, the SPI flash memory is divided into 2 areas: the first, starting at address 0x00000 and ending at 0x6FFFF (not fully used) is the U-Boot program; the second, starting at address 0x70000 and ending at 0x7FFFF (almost fully used) is the W-Load program.

I wrote a small program that can build for you the my-spi.bin file, the BIN file of 512KB you need to re-flash your SPI memory. The program is written in FreeBasic (under Windows), and doesn’t need for installation. Just decompress the .ZIP you can download from attachments in a folder, for example spi-flash and you have the executable to run.
In order to create your my-spi.bin file, you need, obviously, for the submentioned files u-boot.bin and w-load.bin. So, go to the FirmwareInstall folder of your Uberoid upgrade folder (or to the same folder of original rom) and copy the u-boot.bin you find there in the new created folder. For the w-load, you have (often) different file names that all starts with w-load prefix and finishes with .bin suffix, but the right file is the one has inside the same signature you have read in the serial terminal (in our example is UPDATE_ID_1_4_4_0_2_256MB_0150001). If you are in doubt, simply try copying all of them in your new folder and then rename it, one at a time, in w-load.bin. The program is “stupid” and looks for input files u-boot.bin and w-load.bin and produces as output my-spi.bin .
When you start the buildspi.exe, the program generates the output file and shows to video the actual versions of U-Boot and W-Load programs; if some of that versions isn’t the one you need for, simply load another and try again.

Once the file is created and the versions are both identical to the ones you read from serial terminal at the device boot, you have the right SPI file to program into the chip.

The executable file (zipped) can be downloaded here.

In the picture below, you can have a look to a working program screenshot. Hope this will help you.

 

Using SPI programmer to revive bricked Android Tablet

This mini-guide is based on the very useful software SPI FlashROM Programmer 1.9c (C) 2008-2011 by Martin Rehak. Look for SPIPGM.ZIP on author’s page here


This is my version of the programmer’s circuit. I just modified some resistor value from the original one.

More readable PDF can be downloaded here


I also developed a small printed circuit board, mainly for the ZIF socket pinout (it can’t be mounted on prototyping board with 0.1″ spacing).
The 1:1 scaled PDF can be downloaded here

And finally the fully populated board…

I used a ZIF TexTool socket from 3M (RS catalog code 766-980) and modified the resistor values from the original schematic. The reason for this change is to protect the device under programming, ‘cause the SPI flash memories are powered at 3V and the parallel port of PC may run at 5V. So, increasing the resistor values gives less current to the protection diodes built in the memory chip. In practice, the excess voltage coming from the parallel port falls on the resistor and the total current flowing thru the internal protection diode is (Vpp-Vcc) / R where Vpp is the voltage out from parallel port, Vcc is the flash IC supply (3V battery in this case) and R is the resistor placed between the parallel port and the IC. Note that the flash data output has lower value resistor: this is mandatory ‘cause the parallel port has pull-up resistors inside and therefore the LOW level (zero logical) coming from the flash IC makes partition with the series resistor and the pull-up, and rises in value. If the series resistor is too high, the LOW level goes in the zone that is considered UNSTABLE or HIGH for the parallel port input pin and your device will not work !!! Obviously, this means that the data-out pin is not protected as well as the other pins, but for occasional use it may be considered safe enough to operate. A better solution will be to add some level-translation logic. Note the copper band in the picture: it’s only to make easier to unplug the parallel port connector… don’t remove that connector pulling by the wires ! You easily have to solder them again…


Well, now I will describe the step-by-step procedure to program a flash IC with this programmer. You can download here a zip file containing some batch files I wrote to simplify the execution of every procedure’s step, plus a txt file that’s simply a copy of the help screen of the SPIPGM program.
Who needs for SPI flash programming ?
The man that has bricked his Android Tablet changing the wrong bytes with hex editor !
As me…

The last chance, in such horrible situation, is to reprogram the U-boot and W-load that are on the flash chip near the microprocessor. In my WM8650 based Android Tablet, that flash was the 25P40 from ST. It’s a SOIC 8 package, so isn’t too complicate to unsolder from the board. NOTICE: the IC will “die” when unsoldered, as mine did, but if you have the binary file needed to fill the new one, there will be no problems.
Note that in the batch file I used, as source for flash burning, one .bin file called 2711942B.bin ; this strange filename comes from a WM8650.bin I found on the Internet, renamed with the value of its CRC32 checksum. I did this ‘cause there are different binary files with the same purpose (reflashing Android Boot SPI), but in my specific tablet only the one with such CRC32 did the job. Obviously, you need to download the file somewhere (Edited: after some time, I realized a software tool that can build the right BIN file to be used to flash the SPI memory ; read full description in this article) and rename as mentioned to use the batch file without any modifications.
Oops, you also need for a flash memory IC to program 🙂
The original 25P40 from ST was impossible to find in my country, but an equivalent from Atmel is available in the Farnell catalog with code: 171 5441 (AT25DF041A-SSH-B). The component’s electronic signature is unknown for the SPI programmer, but works fine as generic Atmel. As the original one, this flash IC has 4 Megabits (512 KBytes) of reprogrammable memory and costs around 1 Euro for single piece.

Pay attention to static charges ! Connect your body to GND when handling IC

Now, let’s start to program the chip; follow this step-by-step sequence, please…

  • insert the IC in the ZIF socket with DB25 Printer Port Connector and 3V Battery Clip both disconnected !
  • connect the battery clip to the 3V battery pack with special attention to the polarity ! (reverse = destroy)
  • start the “identify.bat” batch file, still without connecting the programmer to the parallel port
(this initializes the parallel port outputs to a safe condition). Obviously, there are errors, ‘cause the programmer is still disconnected.
  • connect the DB25 to the parallel port and run again the “identify.bat” batch.

this time you can see the chip ID that is 1F4401h, that’s specific for the AT25DF041A, but not recognized by program for the type, only for manufacturer (Atmel), but it’s enough.

  • now, run the “unlock.bat” batch. This is necessary to enable the memory to accept writings.


even if the result is “failed”, the unlock has been done.

  • now erase the memory running the “erase.bat” batch. This is not needed for a new IC, but better to do it anyway…


this will take a couple of seconds if all right. If program terminates immediatly, there’s something wrong.

  • and now, run the “program.bat” batch…

the program doesn’t know this type of memory, so prompts for size in Kb; type 512 and go… (note that this step is skipped if the memory chip is fully recognized by the program)

programming has been executed (it will require a couple of minutes or less for the BIN file used).

  • finally, read the programmed flash contents running “dump.bat” batch. It will read the flash contents and store them to arbitrary file name rd_spi.bin ; this will be useful to compare the source file with this readout.

again the program doesn’t know this type of memory, so prompts for size in Kb; once more type 512 and go… (note that this step is skipped if the memory chip is fully recognized by the program)

operation complete… now use a binary file comparision to check if source and readout are equal (I suggest the great open source Frhed to do this job). In alternative you can compare the CRC32, MD5, SHA-1 of both files using the free program HashTab that integrates in Windows shell.

The flash IC is programmed, now follow this sequence to disconnect :

  1. with the IC still in the socket and the battery connected, detach the DB25 connector from the parallel port
  2. detach the clip connector from the 3V battery pack
  3. open the ZIF and get the programmed IC

The new IC has to be soldered in place of the older one. Normally, this isn’t too difficult, but my board pads for pins 5 and 6 were removed by excessive heat during desoldering. This can transform your tablet in a flat expensive electronic rubbish ensemble. I solved the problem using enamelled copper wire (0.2 mm) soldered directly to the PCB tracks and manteined in place by adhesive paper tape. It was very, very hard job. So, please, be patient and carefully remove the original IC from its solder pads. Any excess of heat can damage the chip (and this is not important) and the PCB (and this is terrific) !!! In the picture you can see the “wiring spider” that solved my problem. With this new flash boot and the UBEROID rom placed in the SD card slot, my Android Tablet was finally unbricked.

Added Jul,2,2012 :

I just built a small “tester” circuit that can be used in case of troubles with the programmer. If you can’t program your SPI flash, first of all test if your Parallel Port is really working under the Spipgmw program. The circuit proposed here, has to be connected to the parallel port of your PC. After attaching the circuit, please create a new batch file in the same directory you use for spipgm program and write this command inside:

spipgmw /r 0 16 /d=50000
pause

When you launch this batch, if your parallel port is set correctly, you can see the green led that blinks fast (on my old notebook with 500MHz clock, it blinks at about 10 Hz). If the led DOESN’T BLINK or is always ON or always OFF, there is a problem on your parallel port or the program spipgmw can’t handle it in appropriate way. The parallel port pin 8 is the SCK signal for the programmer, while the pin 18 is GND.

From microSD to standard SD : another “robomod” for tablets

Hello all, my microSD socket was broken ; after many insertions/extractions, it refuses to get the microSD in and spits out two meters far from tablet 🙂 Nice spring inside, small but bastard. Ok, I was looking for a spare part, but can’t find a socket with same pinout… Many types, all different from the one I was looking for. So I unmounted the defective socket and had the idea to connect a NORMAL SD card connector. In the next picture you can look how the tablet was arranged before the modification.

I soldered small enamelled wires from the original microSD socket to the relative pins on a normal SD socket, as you can see in next picture. I also moved the speaker in place of old socket, so there is also a hole in the plastic for sound going out. I had to enlarge the original hole (set for the speaker, originally) to reach the exact measure of a standard SD card. It required only a minute of dremel action 🙂

Now, putting inside a standard SD card, my tablet recognizes it and works fine. I can also use, obviously, the microSD cards, with the usual converter that is supplied in bundle with such small cards and therefore NOW I can use the dozens of standard SD card that cames from my old PDAs, cameras and various devices…
In the next picture you can find a MAD (Manually Aided Design) schematic of the connections 🙂