Hack Correlation

I've recently bought a broken wireless video RX/TX pair off of eBay. The audio was being received properly but there was no video. Since the system works at 5GHz there is no way to easily figure out if it's transmitter or receiver at fault. In the end I managed to get it working and took some pictures in the process.

The microUSB plug on my newly acquired EZCast / Miracast dongle came loose so, obviously, I had to take it appart. The system is based around a single chip: AM8251 - a single-core ARM9 system-on-chip built specifically for this purpose. There's an XDA thread on units similar to this: http://forum.xda-developers.com/showthread.php?t=2632288 and on one of the manufacturers' forums: http://forum.iezvu.com/bbs-en/viewtopic.php?f=2&t=802 The big chip on the other side is a Samsung NAND flash chip, probably this one  (K9F1G08U0E). I don't know what the smaller IC is, but I assume it's the WiFi stack chip. Small review: It does the job fine especially at 720p. Ironically (or not) AirPlay mirroring has less lag and dropouts than Android mirroring. Tested with iPad Air, Galaxy S5 and Motorola Razr. Other users are complaining about a lot of dropouts but I'm not experiencing that. I'm sharing the WiFi through a FritzBox 7390, so perhaps the quality of t...

My apartment building has a central ventilation system built-in. While it does a pretty good job at getting the kitchen smells out it also makes a lot of noise and wastes heat when closed. Out of the many possible solutions I decided on building a cover that goes on top and is activated by the red LED that lights up when the original ventilation system is turned on. This means no messing around with mains - galvanic isolation. After the break, the story of going from this: to this: Along the way there will be some interesting tidbits - original design, capacitive light sensing, low-power techniques and code.

Around three years ago I bought one of the first models of WP7 phones to appear - HTC Mozart 7 - which was very similar to the Android-based Nexus One. Wanted to see what's like to be an early adopter and early player in the app marketplace. I managed to get a free app registered on the app store: Fast Offline Translator EN-DE. http://www.windowsphone.com/en-us/store/app/fast-translator/ccf24cce-d48e-e011-986b-78e7d1fa76f8 I did it mostly for myself as I knew very little German. Not much has changed since. This is the story of doing the development, deployment and update for that app.

I started preparing for doing short YouTube videos - lighting, cameras, display setup, sound. In this post I will deal with the software editing setup and a bit of hardware. Editing requirements: - synchronize videos from multiple cameras - DSLR, point & shoot, camcorder, mobile phones, capture - single video in a split-screen setup showing multiple streams - must be able to zoom in on a camera - subtitles and image overlays - speed boring portions of the video up - switch between microphones, adjust levels and compression The baseline video:  http://youtu.be/KTEGRSdxxxg  - what I expect to get out of the programs. Windows  Movie Maker Everyone's favorite:  unfortunately it's not multi-track and awkward to use. Most of the free / really cheap editing suites fall in this category. Adobe Premiere Too expensive, but the last time I used it (several years ago) was pretty ok. Kdenlive Really good, supports most of the stuff above. Unfortunately it...

There are several projects in which people seemed interested that have a pending follow-up: Txtr Begle alternate software I have managed to buy another one off eBay since one month or so. I've tried setting up the Python bluetooth suite but it's not working on Windows and there are no ready-made binaries. I do not want to force people on Windows to hunt around. I've tried setting up a Java program to communicate via Bluetooth SPP to the Beagle. However this proved extremely unreliable and highly dependent on your Bluetooth suite and hardware adapter. The best solution for now seems to go the txtr way: make a phone app. I will try to develop an Android app that is able to: send screenshots to the reader, send pre-rendered browser pages and perhaps pre-rendered pdf documents. It will probably take one afternoon of research and another afternoon of coding, source code will be made available upon completion. Toshiba TV firmware One week ago I have finally received t...

In this post I will describe a way to build a really cheap device that will allow you to measure USB power consumption and supply characteristics. It's ugly but it takes 15 minutes of your time and a broken USB hub. Then I will take a look at various USB chargers and see how they perform, hopefully not as bad as the one depicted below:

I've enrolled into the UT.6.01x Embedded Systems - Shape the World somewhere back in January/February but never got around to finishing all the exams, yet. It's a microcontroller development class focused on ARM architecture, using TI Stellaris LaunchPad as the platform. https://courses.edx.org/courses/UTAustinX/UT.6.01x/ It's been a mixed experience so far, let me explain why. The good: - using a widely available board, cheap, out-of-the-box. The class can theoretically be completed even without any hardware - awesome teachers - well-structured curricula with a relaxed and modern teaching style - free! (unless you want the certificate) - it touches on a lot of real-world topics, every theoretical experience is backed by practical examples - goes through all the major peripherals without too much detail - automatic grading system that's awesome in theory The bad: - the presentation is discontinuous, videos are interspersed with text, sometimes in a new c...

Got this pulse monitor from eBay, advertised as broken. When paired with a phone it always showed 100 bpm. Searching a bit on the Internet saw that quite a few people had this problem as well ("stuck at 100 bpm"). The front has three buttons, the middle one being pairing/on/off and the left and right ones supposedly change the tracks on your phone media player. Controls seem very similar to the bulk of bluetooth headphones. The backside has the sensor in the upper part - I suspect the pulse-oximeter type one - and two round pads for the charger dock. It's clear now why the bracelet does not give any readings: Due to bad engineering there is no proper strain relief for the wires between the sensor and the controller. I'm inserting a link break here since this post a lot of pictures.

This came out of a "box of things" that I regularly purchase on eBay. They consist of new items that are DOA (dead on arrival). It's a "Spy Pen" or "Spy Stick" - a USB stick with a 4GB capacity that also has a camera inside. The second line under the title makes absolutely no sense, it's like someone used OCR + Google Translate: The end cap was unglued, also the stick would not take a charge. With a bit of force the motherboard slides out, revealing a camera module that's literally plugged in: Great, I get a 4GB microSD for free: Also notice the reset button, I have no idea what's that for, I assume pressing it while plugging the stick in will allow uploading new firmware. Also, the battery is held in position with sticky tape. The other big chip is a 25Q80SCP , 8Mbit flash, probably holding the camcorder firmware. A clearer picture of the battery side with the camera connector. I don't know what this chip is b...

This post is just to make people aware of a project that I did a while back. I was annoyed that the Spektrum DX6i remote that I had did not provide the useful timer features of the DX8i. That is, the countdown timer should be automatically activated when the throttle is actuated instead of requiring the user to manually pull on the trainer switch. Hardware and firmware side together this hack took me around one hour to complete so it should take you much less should you consider to perform it. I've spent another hour retrofitting the display backlight and adding that functionality to the firmware as well. Features: - one PIC10F222 (<1$ in single units) - can detect whether single-pitch (plane mode) or collective pitch is used - starts timer on throttle up, stops it when throttle is removed - backlight is activated when the menu wheel is moved, deactivated after 5s - inactivity warning: after 90s of no usage the remote beeps at you - features can be dis...

I had to install Windows 8.1 Preview over the Windows 8 installation which was giving me problems. The problems went away but yesterday I got a nice surprise: This preview version has expired. Please upgrade to Windows 8.1 using the Store. The computer will reboot in two hours and then every hour. ...or something along the lines. I started downloading the update but then read on some forums that the installation will wipe clean your previous programs and probably settings, only the [useless] apps will remain in place. Here's how to skip the trouble and perform an in-place installation of Windows 8.1 while retaining all your previous programs and settings. You will need to have a valid Windows 8 product key. Steps summary: 1. Go to the 'order page with product key only' 2. Download Windows 8 installer 3. Start the installer and cancel after it reaches 1% 4. Download Windows 8.1 installer from the same link 5. Launch the [new] installer and let it download t...

I have a lot of posts in my backlog that have pictures but no text added to them. Since a lot of them are more than one year old I figured I should take the effort to add the text lest I forget what happened. There is a common problem with the DSO5062B oscilloscopes in that they get a white screen once in a while and require a power cycle to recover, temporarily. The scope seems to be functioning in the mean time but nothing is displayed. The same device is being sold under many different name and brandings: Tekway DST1062B, Voltcraft DSO5062B, Zhongce, Protek, PCE (like mine) but it's exactly the same thing save for the splash screen and printed logo. There's an extensive thread about hacking and modding them on the EEVBlog forum. Here's how the white screen syndrome looks like, see below for the fix:

I've bought a cheap broken laptop on eBay for around 20EUR with the description "turns on briefly the fan and the shuts down, no image". The laptop was actually in pretty good condition, came with a working battery and charger and RAM, but without any hard-drive. A quick search on the Internet turned up the fact that these laptops usually die from heat, having inadequate cooling on the integrated video card. I recovered the laptop by using a makeshift heat shield made from a sandwich of aluminium foil and cardboard an using a heatgun (paint stripper) to slowly heat the chip. A blob of leaded solder was used as reflow indicator, knowing that the leadfree solder melts at higher temperatures and the BGA balls take a while to heat up (being under the chip). A cheap multimeter was used as a temperature indicator, with the thermocouple pressed against the chip body. The cardboard started smoking after a while but this did not affect the operation in any way. The ...

I have been pondering on creating a home network of nodes using cheap slaves and a more powerful master. Since the name did not come up in any Google search I settled upon Node@Home. My idea is to have gadgets spread around the house/perimeter that can report sensor data to a central station and perform certain actions. It will be first used to start the [electrical] heating remotely, check rooms temperature, actuate the blinds on the outside, log the voltage measured by the home-made PSU, start or unblock the Roomba, etc. I am sure that with creating an affordable master node (based on Stellaris Launchpad or Raspberry Pi) and disposable slave nodes will make everyone want to have these things around the house. The minimum requirements for the nodes will be a baseline microcontroller (PIC10/12F, MSP430F, <1$ each) and an NRF24L01 radio transceiver (1-4$). The power of the network will be in the protocol requirements and the software. UPDATE: the draft below is wrong because ...