Stefan Olofsson's Posts (18)

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We are about to release an application for the Lepton with the Raspberry Pi. We are currently using it with the Pure Engineering breakout board but have a custom "shield" or "hat" with RC receiver input and additional features in the works.


The main features are:

  • Unlimited amount of user defined palettes via config file
  • Live video feed for FPV and simultaneous saving of the image stream as .png on the SD card
  • Direct control of the Pi via GPIO pins. No need for SSH to control the Pi

GPIO pins control the following functions:

Input 1 (GPIO 18): Cycle between palettes
Input 2 (GPIO 17): Toggle recording on/off
Input 3 (GPIO 27): Calibrate sensor
Input 4 (GPIO 22): Auto range (set the scale compared to the ambient temperature)


A Palette is defined with 11 simple gradients like this:

# Palette 4, Fire & Ice
palette_4_def_0_rgb=0,0,255 # Lower than min
palette_4_def_1_rgb=0,0,0 # 0% temperature
palette_4_def_2_rgb=32,32,32 # 13% temperature
palette_4_def_3_rgb=64,64,64 # 25% temperature
palette_4_def_4_rgb=96,96,96 # 38% temperature
palette_4_def_5_rgb=128,128,128 # 50% temperature
palette_4_def_6_rgb=159,159,159 # 63% temperature
palette_4_def_7_rgb=191,191,191 # 75% temperature
palette_4_def_8_rgb=223,223,223 # 88% temperature
palette_4_def_9_rgb=255,255,255 # 100% temperature
palette_4_def_10_rgb=255,0,0 # Higher than max

A short demo clip with the app cycling through "white hot", "black hot", "iron bow" and "fire and ice" palettes can be found here:

The app is ready to ship. Only some QA and documentation is left to do.

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APM Planner 2.0 RC2 on Raspberry Pi


I just managed to get APM Planner RC2 running on my Raspberry Pi. I have not tested connecting to an APM yet but clicking around in the interface is much more responsive than i ever thought it would be.

Here are a brief instruction:

Install the required packages:
sudo apt-get install phonon libqt4-dev \ libphonon-dev libphonon4 phonon-backend-gstreamer \ qtcreator libsdl1.2-dev libflite1 flite1-dev build-essential \ libopenscenegraph-dev libssl-dev

Clone the repository in your workspace:
cd ~/workspace git clone

Build APM Planner:
cd ~/workspace/apm_planner qmake-qt4

Run APM Planner:

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RC/FPV mod for DJI Phantom


Pimping/modding your Phantom seems to be popular. Here is the latest offering from our friends at goodluckbuy:

For a USD 329.67, you get a 5 inch display and a CF box to put the RC electronics in but make sure that you check the features before you buy: "For Professionals". (so you really are a professional :-)

The little thumbstick located on the left side looks handy for controlling a gimbal though.

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The Techpod featured in leading hobby magazine


Hi all,

The Techpod and Arudupilot has been prominently featured in the leading nordic hobby magazine "Allt om Hobby" in a three part series on FPV and autonomous flying.

This second part has a nice build log and part three will feature how integrate the  APM into the airframe.

The article can be found at and for all of you who have difficulties reading swedish we offer a 20% discount on the Techpod kit at  (use code techpod20 when checking out)

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Stuck in the mud?


Hard landings with my 3DR quad always puts it firmly 3 inches into the ground, splitting the legs up and destroying the nylon spacers.

I created these very simple bumpers so i don't have to dig up my quad anymore:


They are made from pipe insulation and a wooden hub from a broomstick i had laying around.

I cut up the stick in four 18 mm pieces to replace the nylon spacers and drilled a 3 mm hole in the center.

CA glued the hub to the middle of the foam piece and cut openings for the two legs.

Finally i replaced the two short 3 mm screws with a longer one that goes through both legs and the hub, securing it with a locknut.





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The search for the holy bowl


After scouring most of the shops in my area for a cover/box/hat for my 3DR Quad I found the Orthex 140 0,75 liter kitchen bowl.


The fitting is so good it almost brings tears to my eyes.

It sits on the bottom plate just outside the nut on the arm and I could even reuse the nylon screws on the top.

Highly recommended!

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Multiplex Easystar II just spotted

Coming in December

Was ist neu?

• Kräftiger Brushless Motor, 3fache Leistung gegenüber EasyStar I
• Klapppropeller für weniger Luftwiderstand im Segelflug
• Leicht abnehmbares Höhenleitwerk für einfachen Transport
• Querruder vorbereitet (außer den 2 Servos ist alles im Lieferumfang enthalten)
• Großer Laderaum - Platz für großen LiPo

Quick translation:
Whats new?
Powerful brushless motor
Folding prop
Easily removable tailplane for easy transportation
Aileron prepared (except the 2 servos)
More space inside
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Shame on you, Servo !!!



After almost at year with a strange servo jitter that was taking all the fun out of my UAV hobby i finally found the source. A bad servo.


The jitter was intermittent and made and erratic +- 5 mm throws on the elevator or rudder even when i tried flying  in "manual mode".


The little bastard finally decided show its real face today by giving a "full down" (and i mean FULL) right after start, giving my Easy Star a nice sucker punch right on the nose.


So, Turnigy S 3317 S. Your life was short and noisy, and you will not be missed.

I am moving on now and will look for a more dependable partner. :-)


I know some of you are doing UAV flying for a living. What brands of servos are you using?





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Easy Star Bathtub mod :-)


Here is my quick mod to make it easier to fill up my Easy Star with all the gear. The lid will be held in place with 6 pair of magnets glued to the fuselage. I did the prototype with 3 mm balsa but the next version will be in 2 mm ply. I will probably make a box on top for the APM and better pockets for the XBee and GPS.



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Testing the IMU

Here i have the APM and IMU Shield set up for testing the GPS. I put a small piece of doublesided tape on the GPS antenna and stuck it to the window. After a few minutes of warming up, the GPS started receiving data.

The thingy hanging down the vent is the airspeed controller.

APM is powered by the 5V adapter.

Unpowered board set up for testing the multiplexer. RX on the input pins. Servos on the output.

My 5V adapter with servo connector. With this i can run the APM/servo setup without relying on batteries. The connector goes into a free connector on the servo/tx connector.

Yes, i have insulated the solder joints now :o) .

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Testing my APM

So i finally got my brown bag from Sparkfun. I soldered all the pins, downloaded and installed the Arduino software from here:

I wanted to try the test programs from this page:

I got a FDTI cable from the DIY Drones store for using with my telemetry later, but found out that i can use it for downloading code to the board without the IMU shield attached.

FDTI cable attached and powering the card. The blue LED pulsates when servos are running. I uploaded the RC input testprogram.

After that i tried the "moving servos demo" and found out that the link for the zipfile on the page is wrong.

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Building my UAV

Here is my log on my attempts on building my own drone.

I am going to post just about everything i do and perhaps other can learn from my mistakes :o)

Feel free to comment my work.


I am planning to use 2 Easystars. one for RC training and one for the real thing.

Stuff i am going to use:

Airframe: Easystar

Motor: Turnigy 2835 2200kv

BEC: HobbyWing Pentium 25 A

Battery:LiPo 1800 3S 25C

Prop: APC-E 6x5.5

Radio: Currently a salvaged 4 channel 2.4 GHz from an ArtTech Parkflyer. Will upgrade later.

Assembling the Easystar

The manual was easy to follow, but instead of glue for assembling the fuselage, i used double sided tape. (used for carpets)

I placed the controller inside the fuselage.I am not planning to at full speed so heat will not be an issue (i hope).

Double sided tape in place.

Even more tape...I will not use quite as much on the next Easystar

Closeup of the motor mount. Airflow is needed around the motor so only tape on top and bottom

Fastening the servos

A little tight...easy to fix with some sandpaper

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