Modifying Transcend WiFi SD Card Firmware(fernjager.net)
fernjager.net
Modifying Transcend WiFi SD Card Firmware
http://fernjager.net/post/modifying-transcend-wifi-sd-card-firmware/
5 comments
So one of my problems with the stock functionality is that I wanted it to automatically upload images to my samba fileserver at home, rather than some weird tablet/cloud service. Having some way of printing to my network printer would be awesome too.
I also like the idea of having a tiny, relatively cheap, long running deaddrop wifi hotspot on batteries. Any idea of how long you could run it for from a button battery?
Could you create a half decent mesh network / wifi repeaters with these taped at various locations?
I could imagine a wifi hacking linux distribution like xiaopan might be quite fun too, or something with tunnelling / vpn that can connect to a hotspot and make it safe.
If there were some way to add a few sensors to it without making it much larger / power hungry, that could be really cool, especially considering how much space you have for logging.
I'd like to see if one could be surreptitiously built into a usb cable, or wall wart, so it's powered when the usb cable is plugged in, but otherwise there's nothing obviously special about the usb cable.
I also like the idea of having a tiny, relatively cheap, long running deaddrop wifi hotspot on batteries. Any idea of how long you could run it for from a button battery?
Could you create a half decent mesh network / wifi repeaters with these taped at various locations?
I could imagine a wifi hacking linux distribution like xiaopan might be quite fun too, or something with tunnelling / vpn that can connect to a hotspot and make it safe.
If there were some way to add a few sensors to it without making it much larger / power hungry, that could be really cool, especially considering how much space you have for logging.
I'd like to see if one could be surreptitiously built into a usb cable, or wall wart, so it's powered when the usb cable is plugged in, but otherwise there's nothing obviously special about the usb cable.
Amazing work, I didn't know there was a complete linux system on this! I guess it's cheaper than having a custom hardware.
Potential use case: turn a simple printer equipped with an sd-card slot (to print photos directly on the printer) into a manual wifi printer. The job would be converted to, say, jpeg, sent on the sd-card and then you would have to print it manually.
Other use case: be able to send any file to this SD card, this way you could easily transfer pictures, videos and music to a non WiFi multimedia device, like a TV Tuner, MP3 Player, etc...
Potential use case: turn a simple printer equipped with an sd-card slot (to print photos directly on the printer) into a manual wifi printer. The job would be converted to, say, jpeg, sent on the sd-card and then you would have to print it manually.
Other use case: be able to send any file to this SD card, this way you could easily transfer pictures, videos and music to a non WiFi multimedia device, like a TV Tuner, MP3 Player, etc...
Could you potentially still use the card in a camera, while it was running linux?
Yup! One of the advertised features for the SD card is being able to stream just-captured photos automatically to the mobile app.
The SD card has a script that monitors filesystem changes, and would push the images via curl to the client connected to it through WiFi.
The SD card has a script that monitors filesystem changes, and would push the images via curl to the client connected to it through WiFi.
Man, I thought that getting a "yes" back would lead to a Eureka moment for some awesome use case...but the best I've got is just how cool it would be to show off, haha. Amazing work!
The commercial WiFi power harvester I remembered would be the perfect partner for a WiFi Spy.
Despite the announcement that "on the CES floor, they were able to charge a BlackBerry from 30% to full in about 90 minutes, using nothing but ambient WiFi signals as a power source. " [1]
The device has never been turned into a commercial product. [2]
[1] http://www.ohgizmo.com/2010/01/09/ces2010-rca-airnergy-charg...
[2] http://www.ohgizmo.com/2011/01/07/ces-2011-hey-rca-hows-that...
Despite the announcement that "on the CES floor, they were able to charge a BlackBerry from 30% to full in about 90 minutes, using nothing but ambient WiFi signals as a power source. " [1]
The device has never been turned into a commercial product. [2]
[1] http://www.ohgizmo.com/2010/01/09/ces2010-rca-airnergy-charg...
[2] http://www.ohgizmo.com/2011/01/07/ces-2011-hey-rca-hows-that...
You can make a very simple GSM signal detector using a germanium diode, an LED, and a bit of wire. Tune the wire by cutting it to the right length (a square with sides of 7.5 cm is fine) and solder the diodes in series. Hold a phone near it and send a text message to the phone.
http://www.creative-science.org.uk/mobile_LED.html
Of course, that's a tiny amount of power but it's still there to be harvested.
Not sure what the legal situation is. In England an "artist" was asked to remove their installation of flourescent tubes in a field below power lines. They similarly harvested power. (I can't find that case using Google :-( but here are plenty of others https://www.google.co.uk/search?q=fluorescent+tubes+power+li... )
http://www.creative-science.org.uk/mobile_LED.html
Of course, that's a tiny amount of power but it's still there to be harvested.
Not sure what the legal situation is. In England an "artist" was asked to remove their installation of flourescent tubes in a field below power lines. They similarly harvested power. (I can't find that case using Google :-( but here are plenty of others https://www.google.co.uk/search?q=fluorescent+tubes+power+li... )
Legal situation?!? You're creating a matched impedance point in space.
RF energy harvesting is a bit of a hot topic, there are a number of modules on the market atm. Just search for it on mouser or farnell to get started.
Thanks btw for that LED schematic, so simple. I'm currently tuning a harvester around a BQ25504 and super caps. I'll give it a test next week.
http://uk.mouser.com/Embedded-Solutions/Energy-Harvesting-Mo...
This one contains other energy sources as well:
http://uk.farnell.com/jsp/search/browse.jsp?N=2002+225290&Nt...
RF energy harvesting is a bit of a hot topic, there are a number of modules on the market atm. Just search for it on mouser or farnell to get started.
Thanks btw for that LED schematic, so simple. I'm currently tuning a harvester around a BQ25504 and super caps. I'll give it a test next week.
http://uk.mouser.com/Embedded-Solutions/Energy-Harvesting-Mo...
This one contains other energy sources as well:
http://uk.farnell.com/jsp/search/browse.jsp?N=2002+225290&Nt...
I had a friend who was a phreaker here in the UK and was eventually arrested. At the time there was no Computer Misuse Act. They took hours to read out every "on this date did you make a call to the following number".
He just sat in silence. Eventually he was successfully prosecuted for "Theft of Electricity" from the places he had placed unauthorised phone calls through.
He just sat in silence. Eventually he was successfully prosecuted for "Theft of Electricity" from the places he had placed unauthorised phone calls through.
Does anyone know if the currently available versions of the hardware ( http://www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias%3D... ) are still compatible with these modifications?
I ask because frequently identical outward appearance does not mean identical internal hardware, especially on low cost consumer devices.
I ask because frequently identical outward appearance does not mean identical internal hardware, especially on low cost consumer devices.
That's really a good question. At these prices, I would like to know before I commit to anything.
Why don't companies sell an open/hackable version of this? Surely they could make a killing off the maker / Hacker News crowds.
Actually, Transcend released sources of the firmware : http://www.transcend-info.com/files/Driver/WIFISD_GPL_releas...
For anyone who is interested, there is pretty good writeup here [1] on how to do kernel builds for this card. I also have a WIP of crosscompiling for this card as part of a wifi connectable (using waypoints) automated quadcopter, though I probably won't get to do more on the copter side until the fall.
My current writeup is here [2] - I am in the process of using the 8GB Transcend cards to save a few $$. I also did not experience any weirdness with the first 8 bytes of the initramfs, so I will need to investigate that further...
[1] http://dmitry.gr/index.php?r=05.Projects&proj=15&proj=15.%20...
[2] http://nbviewer.ipython.org/urls/raw.githubusercontent.com/k...
My current writeup is here [2] - I am in the process of using the 8GB Transcend cards to save a few $$. I also did not experience any weirdness with the first 8 bytes of the initramfs, so I will need to investigate that further...
[1] http://dmitry.gr/index.php?r=05.Projects&proj=15&proj=15.%20...
[2] http://nbviewer.ipython.org/urls/raw.githubusercontent.com/k...
For those interested in what happened next: I managed to build and run sqlite, rsync, and dropbear SSH on the SD card using buildroot: http://buildroot.uclibc.org/
I quickly moved onto other interests as I couldn't work out any practical applications at the time.
Feel free to reach out to <me AT fernjager DOT net> if you have any ideas, or want to pick my brain on this project.