Building my Quadcopter

In my last article I described which parts do we need, so we can build a 300$ quadcopter. I will try to explain the building process as simple as possible. In this article I would not mention how to optimize your copter by eliminating vibrations, balancing props or tuning the PID settings of your flight board. In my opinion a beginner should start with the basics and then learn new things step by step. So let´s get started.

In my very first quadcopter I used the X525 frame from HobbyKing, but later I created my own frame. This one is made of plywood on a CNC-machine. If you bought the X525 frame you should start with assembling it first. An assembly manual is included in the package with it. When you are ready with this step, then you should mount the 4 motors on it, without any attached propellers. The Turnigy D2830-11 motors come with a mounting adapter, screws and prop-adapters. On the X525 you don’t need the mounting adapters and can easily mount the motors direct on the glass fiber motor mounts. On the picture below you can see the motor on my actual plywood frame.

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On the second picture you can see it from the bottom side. Here we come to the next step: connecting the four ESCs with the motors. Every ESC has on the one side 3 cables (red, black and yellow) and on the other side 2 cables (red and black). There is also a tiny cable which ends with a male-plug.

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Please note that the ESC on the picture has no connectors on its cables. As I mentioned in my first article you can buy these 3.5mm gold connectors and solder them on the ESC. By two of the ESCs (either Nr.1 and Nr.3, or Nr. 2 and Nr. 4) you should reverse the red and yellow cables. This is because we want two of the motors to spin in counter-clock direction. I tried to illustrate this on the picture below.

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Propellers: The right one spins in clock direction, the left one in counter-clock direction. I had the problem as a beginner that, I didn’t mount the right prop on the right motor and so my quad either not take off or flipped. So take you time and do it right.

Next you should connect these tiny cables from each ESC to your flight board. If you bought the KK 2.0 board or the newer one KK 2.1, you can check the next picture on how to do it right. The cable from ESC 1 (front left) comes on pin1, ESC 2 (front right) comes on pin2, ESC3 (bottom right) comes on pin3 and ESC 4 (bottom left) comes on pin4. The tiny-cables must have this order from left to right: yellow, red, brown.

Then you should connect the other cables of each ESC to the battery. All 4 red cables to the red cable on the battery and all 4 black cables to the black cable on the battery. There are three ways to accomplish that: You have bought a power distribution board and solder the cables on that one. Or you bought a power breakout cable…or you make yourself one.

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Once you have done this, you should connect the receiver (RX) to the board. On the KK2.0 and KK2.1 the receiver-pins are on the left side. You need at least a 4-Channel-RX for a quadcopter and if you are using the KK board it is good to have a 6CH or more. When connecting the cables to the board, beware: from right to left: yellow, red, brown. (Brown for ground, red for VCC and yellow for signal cable). If you want to test, if all the cables are right connected go to the “Receiver Screen” on your KK board and do this: Move the sticks on your Transmitter (TX) and see if it is right indicated on the screen. Probably you should also reverse some of the channels on your TX to do it working properly.

So if everything is connected the right way you can try to make your first fly. To do this you need to “ARM” your flight board. Move the Throttle-Stick on your transmitter down and right and hold it for a few seconds and then release it. In this case the board should indicate “Armed”. Now move your throttle stick very slowly so the motors start spinning. Then move it again very carefully and observe the behavior of the copter. If you have problems such as not taking off or flipping, as said you had mounted the props wrong or connected the yellow and red cables of the ESCs wrong. If so, “disarm” your copter by moving the throttle stick down and left for a few seconds, so the KK board shows the “Safe” screen. Then try to fix the problem and try again. If you cant solve the problem, you can either search on google or comment here.

At the end: Beware, these machines are not toys, they have a lot of power and can heart people. Be careful when flying and have fun. If you find my article useful, please click on the buttons below to share it. Thanks!

02.06.2014 Update: Here you can see my new build with the “SG Adventure” carbon frame.

Каква част от телефона Ви е дисплеят му?

Чудили ли сте се, каква част процентуално от големината на телефона Ви е неговият дисплей? Размерът на дисплея за повечето потребители е от голямо значение, но също така и колко голям е самият телефон. За последното има отношение, каква част от телефона ще бъде, така да се каже, неизползваема: рамката около дисплея, микрофони, говорител, предни камери и т.н. На следващата снимка може да видите едни от актуалните телефони и в каква степен производителите са успели да минимират рамката около дисплея. На челната позиция е LG G2, но това не би учудило повечето хора, тъй като дори с невъоръжено око е видимо колка тънка е рамката около дисплея му. След LG се нарежда Samsung, а на последна позиция е един от първите модели на iPhone. При него дисплеят е само 50% от големината на целия телефон. Стига коментари от моя страна, ето и снимката:

Phone.Screen.Percentage

Source

WD My Passport 2TB – моят нов външен хард диск

Преди близо 3 години писах колко бях очарован от моя Samsung G2 Portable 640 GB външен 2,5 инчов хард-диск. Тъй като гигабайтите на Samsung диска с години все намаляваха имах нужда от нов с повечко гигабайти. Задължително исках да е отново компактен и да се захранва директно от компютъра през USB-порта, тоест да няма нужда от допълнителен адаптер. Спрях се на Western Digital My Passport 2TB. Най-първият ми външен хард-диск през вече далечната 2006 година беше точно от тази серия на WD: My Passport. Големината му беше цели 120 GB. Диска все още работи безпроблемно.

Новият хард-диск ми беше донесен от Дядо Коледа и мога да кажа, че качеството му е отново на много високо ниво. Изработката му е добра и изглежда много стабилен. За разлика от предните ми два външни хард-диска този поддържа USB 3.0. За съжаление нямах възможност да тествам скоростите на прехвърляне през бързия USB 3.0, a само през USB 2.0 порт. Средната скорост на копиране върху него беше 24 MB/s. Успях да копирам към 500 GB за няколко часа и през тях нямаше абсолютно никакви проблеми. Хард-диска е съвсем малко по-шумен отколкото стария Samsung G2, но с оглед на по-големия вграден в него 2 терабайта диск мисля, че е нормално. Като заключение мога да кажа, че съм много доволен от новата си придобивка и да го препоръчам абсолютно като избор за външен 2TB диск. Може да го купите от тук.

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How to build a Quadcopter

A few years ago I read an article about the so called “Drones” and I was very excited about the idea of building my own drone. Last year after my final-exams I had a lot of time, so I decided to build my first QuadCopter. My budget was about 300 $. The most popular website I found was: hobbyking.com. So I started buying the parts. Here are the ones I bought, but you can choose your own if you have a bigger budget:

First you need a frame, where you will mount the motors and the electronic-parts. I chose a X525 Glass Fiber frame for 15.25 $. It looks cool and is very durable. A year after I work on my own frame, but as a beginner it was the best choice.

For a QuadCopter you need naturally 4 electric motors. I chose this one: Turnigy D2830-11 1000kv for 9,5 $. I’m still using these in my own quadcopter. There are some better motors, but they are more expensive too.

For all types of MultiCopters (Quadcopter, Hexacopter, Octocopter, Tricopter) you need the so called “speed controllers” (ESC). A speed controller is the electric part, which regulate how fast your motor will spin. My choice was a  HobbyKing 30A BlueSeries Brushless Speed Controller. One of these cost about 11 $. As you have 4 motors on a quadcopter, you also need 4 speed controllers. In February I was able to upgrade the firmware of the speed controllers with the very popular SimonK. It is specially created for multirotors and there was a big difference before and after the software upgrade. To do this you need a little bit of solder skills. As I said if you have a bit bigger budget you can directly buy four of the Afro 30A Speed Controller, which is already upgraded with the SimonK firmware. This one cost about 14 $.

Probably the most important part of every multicopter is the Flight Controller or Flight Board. There are some extremely good flight controllers such as the DJI Naza. Here is a link for the DJI Products Website. This one cost about 300 $. So it was too much for my budget. I decided to get the Hobbyking KK 2.0 Board for 30 $. For that price it is a very good flight controller, but it lacks the altitude hold because there is no barometer on the board. My copter is still with this board and it still works well after a lot of crashes. Last month Hobbyking introduced the successor of the KK 2.0 board – the KK 2.1 board. Practically it is the same board with upgraded software and some upgraded sensors. It still doesn’t have a altitude hold. And it still costs 30 $. Another good flight controller is the APM 2.6 by 3D-Robotics with GPS. This could be my next flight controller, but now I don’t have the 240 $ for it. There are clones of this board, but is always good choice to support the original one if you have the resources $$$.

For a quadcopter you also need 2 x Standard Rotation and 2 x Right Hand Rotation propellers. I decided that the best propeller size for my quadcopter build is 10×4.5. So I bought this pack for 2,6 $ from Hobbyking. Well I bought 3 packs for the case I will crash my quadcopter. And… I crashed it many times… so it was a good decision.

At first I bought a 2200mAh 3S 40C LiPo battery for 15$ and it was ok, but then I decided that I need more flight time, so I bought also a 3300mAh 3S 30C LiPo for 26 $. The first one has 3.5mm connector and the second one 4mm connector.

As a beginner I didn’t knew that the KK 2.0 flight board comes without cables to the receiver. So I didn’t buy these Male to Male Servo Leads for 4 $. Then I bought these on ebay for much more.

You will need some 3.5mm gold connectors and 4mm gold connectors for the speed controllers and for the battery. If you don’t want to solder, then you will need to buy presoldered ESCs (such as the Afro 30A speed controller) and this 3.5mm Power Breakout Cable. The last one can be used with the 3300mAh 3S LiPo battery. I also bought some zip ties.

Annnddd last but not least you need a transmitter for your drone. For a multirotor a simple 4 Channel radio will be ok. The KK 2.0 board have also a Self-level-feature, so you will need 5 CH. My first choice was the DX6i by Spektrum. It is a very good radio but it was too expensive for me, so I got the cheap Turnigy 9x. It is also a very good 9 Channel radio for 50 $. It has not the design and build quality of the Spektrum, but for a beginner it was and still is a good choice.

So my order was about 230 $ and 40 $ for shipping, overall 270 $ for my first quadcopter. It is still not a small amount of money, but the feeling of building your own drone and then see it flying … priceless.

p.s. In the next weeks I will also blog about the build process and my troubles with the quadcopter.

Silver Oil Ratio

The price of silver dropped in the last days significantly. Oil prices are relative stable at the moment. Since I am interested in this shiny metal, I wanted to know if there is any correlation between silver and oil prices. Oil is needed for almost every aspect of our life, so must be the case with mining silver. On the Internet I found an article from 2005 [link]. It was very interesting to read it, but it is a bit outdated. So I decided to make a simple Excel-Sheet for my self for the period between 2006 and 2013. In the chart you can clearly see the correlation between both prices. If you find this helpful, you can share it with the buttons below.

Download Excel-Sheet

HTC One серията с +25GB Google Drive

Новият HTC One Max ще получи +50GB за две години в Google Drive. HTC One както и HTC One Mini също трябва да получат допълнителни +25GB след актуализиране до HTC Sense 5+. Стандартно всеки потребител на Google Drive има в момента на разположение 15 гигабайта. Повече информация може да намерите на следната страница на Google, както и как да активирате допълнителните GB за вашия Google акаунт: Google Drive offer for HTC Android devices

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Commodity prices in Weimar Republic 1913-1923

This is the first post I will write in English, so please excuse my mistakes. I saw videos on YouTube, where some people, including Mike Maloney in his “Hidden Secrets Of Money”, told us that an ounce or two of gold had bought a house in the past. I think Mike Maloney said, he didn’t search for this, but heard it from the Swiss investor Marc Faber. So I wanted to know if this is a real fact or not. History and specially the history of money was ever interesting for me. For few years I have been living in Germany and I have access to the library of my university, so I started looking for old newspapers. And as many other things, the Germans have done a very good job in scanning old newspapers. It was a bit hard work, because of the old German font used in the books and newspapers. Anyway… in the next lines I will not only present to you some commodity prices, but some other interesting facts in the time before the World War I and the Hyperinflation in 1923.

As first I want to show you two of the major currencies in Europe at this time: The Swiss frank and the Goldmark. Switzerland at time was part of the so called Latin Monetary Union. So the value of the Swiss frank was: 1 Frank = 0,290322g Gold = 4,5g Silver. The German Goldmark itself: 1 Mark = 0,358g Gold = 5,55g Silver. At this way you can always determine what was the commodity price in gold and silver. So lets get started!

1913-09-11

House with garden 28 000 M = about 322 oz. gold [1]

1913-09

Car = 1 600 M Motorcycle (second hand) = 250 M
Bicycle = 25 – 40 M Pushchair = 15 M
Sofa = 25 M Stove = 20 M
Basler Bank: Interest rate 3,5% – 4,5% House (Between Karlsruhe and Freiburg) = 6 000 M.
Rent 3 floor apartment = 400 – 600 M 250 decare near Basel (covered with forest) = 40 000 M
Rent 5 floor apartment = 1000 M House (5-6 rooms) Freiburg = 25 000 M
Rent 10 floor apartment = 1500 M House + (32,5 decare) near Freiburg = 12 000 M

1914-06-02 [2]

4 Pound white bread 0,60 M
4 Pound rye bread 0,81 M
1 Pound veal 1 M
1 Pound pork 0,85
1 Liter Milk 0,23 M
4 Eggs 0,50 M
 

1914-06-10[3]

Car 6 P.S. = 450 M 2,5 storey house (Freiburg) = 18.000 M

I also find an interesting article, called “Papier statt Gold” or in English “Paper instead of gold”. It describes how the Germans at that time (1913-09) do not very like the Paper-Marks. Of course you can always change your Paper-Marks for Goldmarks because of the Gold standard, but the people prefer the Goldmark instead of Paper-Marks. You can see in the table the percentage of Paper- and Goldmarks in circulation [4]:

 

1908

1911

1912

Banknotes

27,76%

28,37%

30,08%

Goldmarks

72,24%

71,63%

69,92%

 

Then in August 1914 the World War I started. Weimar Germany needed money to finance the war. And at the beginning of august the gold standard was removed. I found another interesting article [5]: Many business owners didn’t want to accept the Papermarks. They were committed to accept the Papermarks or their localities would be closed.

1919 – So the war ended, Germany have lost and should pay a lot of reparations. The economy was bad and there was a lot of unemployment at this time.

1919-12

Apple/Pear 0,60 – 2 M
Chicken (alive) 14 – 20 M
Hen (alive) 25 – 30 M
Goose 60 – 75 M
Duck 25 – 30 M
Dove ?!? 5,50 M
Ladies shirt 18 – 27 M

1919-12-20

1 Swiss Frank 874 M

1919-12-28

Hotel Karlsruhe 185 000 M
Hotel Basel + 125 decare 185 000 M
Cafe-Hotel 70 000 M
Small Hotel 70 000 M
 
If we here make simple calculation: a hotel in the town of Basel costs 185 000 Marks. In Swiss frank about 212 CHF. As I noticed the Swiss frank had a value of 0,290322g Gold. So at that time the hotel really costs 2 ounces of gold.
 
I also found what was the income tax at the end of 1919 in Baden (region on the east bank of the Rhine in the southwest of Germany):
 

1919-12 Income Tax in Baden

1 000 M 100 M
10 000 M 1 450 M
21 000 M 4 110 M
31 000 M 7 080 M
50 000 M 13 000 M
101 000 M 38 900 M
200 000 M 100 000 M
301 000 M 166 300 M
500 000 M 60 %

1923-01-01

1 $ = 7 267 M Flour (50kg) = 42 000 – 47 000 1 kg (900) Silver = 144 000 M

1923 Banknotes in circulation

1923-02-23 3 123 Milliard Mark
1923-03-24 4 000 Milliard Mark

1923-03-04

1 $ = 22 600 M 1 Swiss Frank = 4 275 1 kg (900) Silver = 445 000
Kidney bean = 1 600 M Pea = 1 600 Rice = 1 700

1923-04-05

1 $ = 21079 M 1 Swiss Frank = 3865 M 1kg (900) Silver = 420 000 M

1923-10-19

300 decare = 120 000 Goldmark House (5 rooms) = 25 000 Goldmark
Very interesting fact: At the pick of the hyperinflation in 1923, the people stopped accepting the Papermarks, and accepted again only Goldmarks. So at that time a house costs again as before the war about 288 ounces of gold.
 
At the end I will show you two more tables with prices:
 
Deutsche Bank share in Mark between 1913 and 1923
1913-09-01 247
1913-09-30 248,25
1914-06-02 239,75
1914-06-09 240
1914-06-29 237
1919-10-28 250
1919-12-01 249
1919-12-18 260
1923-01-03 8 350
1923-01-29 20 000
1923-02-28 27 750
1923-03-28 22 800
1923-04-27 28 500
1923-05-28 50 000
1923-06-29 300 000

Flour (100kg) – Q1 1923

1923-01-22 84 000 M
1923-01-29 112 000 M
1923-02-05 140 000 M
1923-02-12 125 000 M
1923-02-19 110 000 M
1923-03-04 140 000 M
 

So at the end, for every commodity there are picks and downs. It depends on: where the house is, in witch country it is, in witch currency and what the people need more (after a war: house or food) and so on.

I hope you will find my post interesting and if so, please share. Thanks and have a good day!

p.s. And a photo of 20 and 50 million Mark from 1923

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[1]Freiburger Zeitung 1913-09-11 Zweites Morgenblatt, Page 3.
[2]Freiburger Zeitung 1914-06-02 Zweites Morgenblatt, Page 2.
[3]Freiburger Zeitung 1914-06-10 Zweites Morgenblatt, Page 3.
[4]Freiburger Zeitung 1913-09-21.
[5]Freiburger Zeitung 1914-08-04.