12th hour in the air =)

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Finally, the weather got better, and I had time for a flight lesson. The aircraft was without a radio, but it is OK since we were flying in class G airspace. We just had to be extra cautious when looking out for airplanes. In the beginning, I did a few stalls, and later my instructor simulated engine failures where I should find a field for landing. Before landing, we also did a touch-and-go.

Flight lessons

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Last year in September, I started taking lessons towards a private pilot’s license (PPL) for airplanes. There is an aviation club nearby (http://www.eslovsflygklubb.se/) that also functions as a pilot academy. It is a great feeling seeing the earth from above =)

Here are some videos from my first few flight lessons. More will come. Subscribe to my YouTube channel if you want to get updates immediately.

Dirty Filthy PCBs

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I just received 10 PCBs that I ordered from dirtypcbs.com a couple of weeks ago. I have to say that the quality is amazing. For $14, they are not dirty at all! They lack gold-plated pads, unlike PCBs from OSHpark, but if that is none of your concerns, then it’s a go! I don’t claim that OSHpark is obsolete now, but for simple prototyping, when you want to be allowed to make mistakes, dirtypcbs are filthy enough to allow you to do that.

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Mooltipass compile and flash guide for MacOSX

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Mooltipass

Mooltipass is an open source offline password keeper that started off at Hackaday as an idea from Mathieu Stephan. I am one of the few lucky beta-testers and as such I would like to explain in this guide how to compile and flash its firmware from source. This guide is written for Mac OSX 10.9.

1. First of all: I DO NOT TAKE RESPONSIBILITY IF YOUR MOOLTIPASS AND/OR DVD PLAYER EXPLODES AND/OR YOUR WIFE DUMPS YOU! FOLLOW THIS GUIDE AT YOUR OWN RISK, IT REPRESENTS THE UNOFFICIAL VIEW OF THE VOICES IN MY HEAD.

2. Second, get the required tools. If you don’t already have MacPorts, download and install it from their website.

3. Once this is done, install git, binutils, gcc, avr-gcc, avr-libc and dfu-programmer from MacPorts. Just a note: I already had xcode installed on my mac, so this did it for me. If you install all of these tools and still have problems at compiling, try installing the Command Line Tools.

sudo port install git binutils gcc48 avr-gcc avr-libc dfu-programmer

4. Get the latest source code from github:

git clone https://github.com/limpkin/mooltipass.git

5. Define that you are a beta-tester ;) and compile the source code:

cd mooltipass/source_code
sed -i "" "s/XXXXXXX/BETATESTERS_SETUP/" src/defines.h
make

6. Set your mooltipass in DFU mode:

  1. Disconnect your mooltipass (if connected).
  2. Insert your smartcard upside down, with the chip-side up.
  3. Connect your mooltipass.

7. Flash your newly compiled firmware:

sudo dfu-programmer atmega32u4 erase
sudo dfu-programmer atmega32u4 flash mooltipass.hex

8. Disconnect your mooltipass, remove the smartcard, connect your mooltipass and insert the smart card.

9. Profit?

Folk racing

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Racing is something that I always wanted to do but never really got to it. A couple of weeks ago, I went folk racing with a friend at a nearby track. It was great fun! This month I booked a second time, and in the future, I will probably get my own crappy racing car provided that I find a parking spot for it.

Here is a video from the race a couple of weeks ago:

WiFi Thermal Printer with Arduino

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I have been working on a wireless thermal printer for an application that I have in mind.

The system is composed of the following parts:

The WiFi shield uses the SPI bus, which leaves the serial port free for the printer. In the video below, you can see a simple example of Internet-to-Printer connectivity. As a standalone system with no connection to a PC, the system is started up, and it pings Google. When a successful ping response has been received, it prints the letter “P” with the printer. More information could have been printed here, but since I use an Arduino Diecimila with very little memory, the program only fits on the microcontroller as it is.

  • The Arduino with the TI CC3000 WiFi shield.
  • Thermal Printer + WiFi Shield + Arduino

Here is the code used in the example:

DIY Cellphone, Part 2

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The last couple of days, I have been trying to put my cellphone together. Using soldering paste with lead requires good ventilation. The fumes are poisonous, and you shouldn’t breathe them. That’s why I had a big fan by my side. Your friends are; soldering paste, flux for the hard ones, a soldering iron, a tweezer, and patience.

I discovered that I didn’t receive the correct LiPo charger, and I haven’t been able to power the phone to program and use it. I have contacted the supplier (Electrokit), and I am sure they will find and ship the correct one. Still, I have to wait over the weekend before I can use my phone, which is not fun =(

Here are some pictures from the soldering procedure:

DIY Cellphone, Part 1

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I believe in a society like today, we need to have better control over our communications. Today’s smartphones have been accused of being devices of mass surveillance. Therefore I have decided to build my own cellphone. I found this guide on the internetz, which describes an open-source cellphone platform based on a GSM module and an AVR microcontroller. I selected it as a starting point for my cellphone. It will most certainly receive software updates from me (I want snake!), and probably even hardware updates in the future. Yes, I know, GSM is not secure at all, and it is vulnerable to man-in-the-middle attacks, but I still prefer the man-in-the-middle over nsa-over-the-internetz.

Enough jabber, for now, let’s get to the fun part! So far, I have received all the needed components from the Bill of Materials (BOM) for the phone’s LCD version, besides the PAS414HR-VA5R SuperCap, which has been discontinued. Since the proposed replacement part isn’t good enough, I managed to find some leftover PAS414HR-VG1 at Farnell and instead ordered a few of those. It will take some scratching and soldering to fit it on the PCB, but its values are correct. Since I am living in Sweden, I had to find alternative suppliers for my materials (Electrokit for some electronics, In-Time for the antennas, Farnell for the SuperCaps). Some had to be ordered from DigiKey anyway. Try to keep your parts ordered from DigiKey below your country’s import tax threshold. Otherwise, you might end up paying import taxes like me, which is not fun.

Here is a picture of the PCBs from OSH Park, which are of excellent quality. More will come once I receive the SuperCaps and start soldering the cellphone.

Cellphone PCBs from OSH Park.
Cellphone PCBs from OSH Park.

Harlem Shake with a Stewart platform

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I had a project assignment to do for one of my university courses (Numerical Analysis). The project was about modeling a Stewart platform in MATLAB. I took it a step further and animated a Harlem Shake of the final result. Enjoy the video!

Here is the code that I have written to generate the images compiled in the video above: