Showing posts from 2015

Recovering from a hard bricked LG Optimus G E975.

Something a tad different this time. I am writing this so I would remember not to fix bricked android phones anymore. Soft brick is easy, boot into download mode, flash the stock firmware and bingo. Hard brick is trickier; the phone is basically a paperweight. The bootloader is messed up so the phone is completely unresponsive – no download mode, no fast boot, no nothing.

So the adventure starts at the beginning.

I managed to get my hands on a bricked LG Optimus G E975. During a wipe in recovery mode, the user rendered the phone useless. Now was my time to work my magic.


Download E975 firmware.bin
Install drivers
Open the program

Select the downloaded firmare.bin file.
Find a good location where to extract the files(for example C:\lg)
Click Extract and wait.
Make sure AP chipset is G.
Choose the right COM port (whatever port Windows assigned)
Find the location specified in step 2. (C:\lg)

If it works the first try you are in luck. If…

My take on the PA0RDT Mini Whip antenna.

I like shortwave radio because you can receive signals from all over the world, also there are all kinds of mysterious signals to explore.

In the grand scheme - the lower the frequency, the bigger antenna you would need. Well, there are all kinds of antenna designs but I like to think like that way. For example, I have a 27 MHz dipole on my roof that is around 5.3 meters long. If I wanted to listen to lower frequencies ~ around 3 MHz, for optimal performance I would need around 50 meter antenna, so using dipole for lower frequencies is not very space efficient, especially if you do not have any room.

So I decided to build the Mini Whip antenna. It is popular, simple to build and on paper receives frequencies from 10 kHz to 30 MHz, and also it is super tiny.

There are some variations between different designs, but the basic idea is the same.

The schematic I followed.

During my tests it performed well, I was able to receive DCF77 signal for the first time. All other bands seemed to work as w…

MIRRORCROCODILE - a tool that helps to mess around with 433Mhz devices

I think the coolest thing to do with computers is to interact with the real world. Computers used to have parallel ports. Parallel ports made it super easy for tinkerers to interface with the real world. I have seen a lot of projects around parallel port but they are the thing of the past. New computers do not ship with parallel ports – nobody uses them – only people, who want to flash LEDs, when they receive a new email etc.

What is the next best thing? What is the thing that every computer has? USB is hard mess around because it is too advanced for simple projects. You need to use controllers and it gets complicated fast - at least for me.

So then, inspired from that triggertrap post I realized – SOUNDCARD. Every computer/phone has a headphone jack. But what happens if you want to listen to music and flash LEDs? Then you buy a cheap USB soundcard from eBay and use that as a platform (You do not want to fry your onboard soundcard, I think).

Soundcard is basically an ADC and a DAC (micro…

Homemade Triggertrap remote trigger

I was reading an article about a Kickstarter project that failed miserably, and found out a company called Triggertrap. Their project failed but they were already selling remote triggers for cameras. Remote triggers are fun, they allow to control camera remotely……..

I have never owned a proper remote trigger, I have always used the time trigger function on my camera.
The remote costs around 42 euros but the app is free. So I thought it should not be hard to build my own remote that works with the app.

The schematic:

Well, ideally you should use optocouplers to separate the electric circuits, but I like to live dangerously.

It fits neatly in this little red box. Now I can take selfies 10 meters away.

Well really, quite useful thing while doing time lapse photography.

RFID experiments

Radio-frequency identification (RFID) is a way to use electromagnetic fields to send and receive data wirelessly. The system consists of two parts: reader and a tag.  Tags can be passive or active. I think the most popular are passive tags. Meaning, there are no batteries needed, the power comes from the reader. The reader constantly sends out an interrogation signal and when a tag absorbs the energy and powers up, it radiates back information from the embedded chip.

Then it divides further - different frequencies, generations, encryptions etc.

Also one popular part is NFC (Near Field Communication) which has better security and other improvements. Latest phones usually come with NFC read/write capabilities built in.  So you can pay with your phone or touch phones together to share information. A lot of possibilities.

RFID/NFC is quite popular in our commercial world.

Anti-theft – stores use it to stop people stealing stuff.
Tracking people - putting tags inside shoes to track people, some…

Voice inversion with GNU radio

Voice inversion is security through obscurity. It is an analogue way to obscure transmission content.

There are all kinds of variations of this scrambling, offering different levels of security. The general idea is they take a signal and as the name recommends - inverts it. Meaning low frequencies become high and vice versa.

This scrambling is a pretty old technique. It prevents people from just listening in. Nowadays with fancy software and computers it is pretty obsolete. IT IS OBSOLETE *cough*Elion*cough*.

Software has been floating on the internet a long time, probably used by HAM radio operators. Basic rule is that you take the output from the radio receiver and pipe it to the computer. Computer with its magic outputs it as human understandable information. Now ,for example, it is useful to use a SDR.


Wikipedia suggests:

In the simplest form of voice inversion, the frequency "p" of each component is replaced with "s-p " , where "s"  is the fr…

Infrared black magic

Lately I have been fascinated by devices that use infrared. Quite old technology but fun anyways. IR remote controls are quite popular because that’s the cheapest way to remotely control a device. Negative sides? – Line-of-sight range.

So I stumbled across this thing called TV-B-Gone. It turns off/on every TV known to man. Quite cheap and popular thing. So I was interested to make my own little device using Arduino. Using sample sketches with libraries – easy.

Two TVs / Samsung and Philips


Next idea was to capture IR codes and then replay them. Transmission part stays the same but now we need input. I used commonly available IR photo-detector module. It has everything in one package. Again using a library – nothing fancy.


So my friend has a Samsung phone that has an IR blaster built in. That thing works great, a lot of apps and easy to use, works great. I don’t have that luck with me so…

Wiring little wires to stuff or “How did I get fingerprint scanner”

So I had/have a semi-old dead laptop. The motherboard is dead, everything else works. It’s a Dell XPS M1330. It has a fingerprint scanner that made my curious. How does it work? How is it connected and can I use it?
I ripped the laptop open and extracted all kinds of fun stuff including the fingerprint sensor.
It has a little chip with a writing  / / TCD42A1DN0 / /
So I started investigating.
First thing that threw me off was the 6 pin ribbon cable (USB typically uses 4).

Finding ground pin is the easiest – Found that.
Found the power pin- It was a line that had a capacitor connected with the ground. So I assumed this was the power pin.
Two pins are unpopulated.
Two pins are connected to resistors – starts to seem like USB data lines~.


Interfacing it.

Typically all internal laptop stuff uses 3.3V. So that seemed a safe way to go. I need to use a voltage converter to step down from 5V.

It has a ribbon cable, so that’s a no go. Removed that and the plug and decided to connect wires direc…