ligi's Tec Blog

Work

2009-12-11T08:26:00.000-08:00

thats the stuff im doing at work atm:

POLYMAP3 is developed under an open source license (LGPL). POLYMAP3 is based on Eclipse/RAP, OpenLayers, GeoTools, uDig and a lot of other great open source software components.

POLYMAP3 aims to provide a multi-user SDI platform. Supporting the power user with an ad-hoc data workbench, the admin user with configuration workbench and the end users with a simple to use web client and OGC services. UI is the web browser.

http://polymap.org/wiki
http://polymap.org

Controlling Mikrokopter with a SpaceMouse on an OpenWrt Router

2009-07-03T05:05:00.000-07:00

I improved my SpaceMouse MikroKopter flying setup so that it's now more practical. In the old setup for piloting the MikroKopter with a SpaceMouse ( look here) - I used my notebook for running Riddim. This mainly had 3 drawbacks:
- setup time until i can start flying with this setup was very high
- not reliable enough ( I install software and do experimental stuff on my notebook too often to believe it could be a reliable MultiKopter Controller )
- in the notebook setup piloting was only possible when sitting

In the new setup i use one openwrt router ( asus wl500g premium ) to run the riddim software:

The Datalink to the Mikrokopter is done with ZigBee Pro - which is connected over one MK-USB to the router ( later i can get rid of the MK-USB and use one of the 2 native serial ports in the router to save weigth and power).
The keyswitch to start the mikrokopter and the other switches are connected to an mini gamepad i bought for ~5Eur and took apart to connect wires.

The whole thing is powered by a 2S LiPo ( to ensure the 7805 is not getting to hot).

résumé

Pros:
- very intuitive ( you move the mouse as you want your QuadroKopter to fly )
- one free hand - only one hand needed for flying ( so you have one hand free for operating other functions, for a cigarett, a mobile phone ,a tissue , ... )
- keyswitch to start the Multikopter often lets spectator smile ;-)

Cons:
- router needs ~1min to boot ( i deactivated some stuff in the init.d allready but i have some more options left i can try like boot_wait_time, removing modules i dont need , ... - i hope i can get it ready in <30s )
- landing ( more touch down than soft at the moment with preasure sensor )
- not really suitable for acrobatic flight

credits
- xm for help on porting to openwrt
- sublab for infrastructure

Quadrokopter@GrundrechtsGeburtstag

2009-05-24T03:28:00.000-07:00

Additional Pics from leon:

bright future

2009-05-09T07:06:00.000-07:00

Quadrokopter + Oktokopter = Dodekakopter

2009-05-09T05:01:00.000-07:00

Yesterday we had the Maiden-Flight of our DodekaKopter:

6km DUBwise Connection

2009-03-26T09:05:00.000-07:00

Holger showed up with a nice improvement of the Range-Extender which gives the possibility to have more than 6km distance between the MK and the Mobile-Phone. The related Forum Post is in german, but perhaps you can see on the Pictures what it its all about ( Hint: big antenna ).

Quoting Obama

2009-03-24T04:23:00.000-07:00

I never thought i would quote an US-President for speaking words of truth so soon but now I can - I really like this Quote:

MR. OBAMA: Well, and part of what happened over the last 15, 20 years is that so much money was made in finance that about 40 percent, I think, of our overall growth, our overall economic growth was in the financial sector. Well, now what we're finding out is a lot of that growth wasn't real. It was paper money, paper profits on the books, but it could be easily wiped out.

And what we need is steady growth; we need young people, instead of -- a smart kid coming out of school, instead of wanting to be an investment banker, we need them to decide they want to be an engineer, they want to be a scientist, they want to be a doctor or a teacher.

And if we're rewarding those kinds of things that actually contribute to making things and making people's lives better, that's going to put our economy on solid footing. We won't have this kind of bubble-and-bust economy that we've gotten so caught up in for the last several years.

* full transcript
* full video

DUBwise J2ME Installer

2009-03-02T18:04:00.000-08:00

With J2ME there is always the trouble with lots of JAR and JAD Files to handle device differences. It's theoretically possible to write a one-fits-all application in J2ME - but only with a lot of drawbacks. One big problem ist the usage of special APIs or profiles. The other big thing is that you have to include different ressources for the same thing to (really) 'work' on the device. Handling these problems on the device leads to very big and slow applications. Keep in mind that some people still pay a lot of $$$ for mobile bandwith and/or have slow devices. Thats why one-fits-all jar's are very rare and DUBwise isn't one of it. But it leads to problems in finding the right jar/jad for a lot of people. And until now this problem was solved by a human (me) by answering questions from users. But I like the idea of letting computers or machines do the monotone work ..-)

The most common solution to this problem out there are device lists - but these lists are never complete and need a lot of maintenance (there are a lot of devices emerging every month). The solution for DUBwise is the "DUBwise Installer" which is a small (<10kb) one-fits-hopefully-all application which assembles information about the device, selects the right jar/jad combination and gives the possibility to install it.
This is an easy way for users, but the coders side had some stepping stones. Now i had to build all possible combinations - and this was more of a problem than it sounds because there are 3456 combinations possible actually:
6 - sound packs
*6 - image packs
*3 - firmware packs
*2 - bluetooth usage
*2 - cldc1.1 or cldc1.0 usage
*2 - jsr179 usage
*2 - FileConnection API usage
*2 - deviceControl usage
----
=3456 Jars

This is more than one Gigabyte of jar and jad files and took ~6 houres to build on my Core Duo. Reducing the diversity was not an option for me - so i had to work on Filesize ( i didn't want to crash the svn server on the host project) and on compiling speed.
First tests with my standard packers bzip/bzip2 where very disappointing because they did not siginificantly decrease the size - the very minimum i got where ~800MB - and i had a lot less in my mind because i thought that the entropy is not very high and i can compress this content very good (i could explain why verbally but im not able to write it down ..). Then i searched the net a bit to find a better packer - i stumbled over 7zip - but the tests on the site i found only showed a small difference (which is anyway good for the content they tested - but not the jump i searched for). So i gave it a try and the results where amazing - I got a 17MB File with the default settings and compressing/decompressing are rather fast.
The next problem was the build time - until now i had no problem with it because it was less than 10s/build which is ok for building an app - but not ok for building an app 3456-times ..
The most time consuming part were the jumps to ANT where the sources are preprocessed, compiled and stuff. Now i do this only when the code is changed and just bring the right ressources into the jar otherwise.

Links:
- jar and jad of the Installer
- Source Code of the Installer

David Pogue on Cellphone Trends for 2009

2009-02-22T14:48:00.000-08:00

DUBwise Graph Speedup

2009-02-16T08:07:00.000-08:00

The Sensor-Graph in DUBwise ( actual trunk ) is now much faster and the speed is adjustable:

DUBwise Graph speedup from ligi on Vimeo.

DUBwise ScreenCast Test

2009-02-11T10:23:00.000-08:00

I am trying to make a screencast of DUBwise - this is a first result ( sorry for the poor audio ):

DUBwise screencast test from ligi on Vimeo.

Oktopussy Failsave Test

2009-02-10T02:39:00.000-08:00

The most interesting thing about 8 Engines is that some ( up to 4 ) can fail without causing a crash. We made a little video while we tested this "Feature":

Oktopussy Failsave Test from ligi on Vimeo.

DUBwise RC-Mount

2009-02-06T07:03:00.000-08:00

Since i build the DUBwise Range extender - there are some new usecases in which i use dubwise while the MultiKopter is in the air. For that i needed a mount that i have my hands free for flying. This is the mount i build from parts i found in my Hobby-Room ( price of parts <5$ ):

weight of 87g with sun-protection - which is very ok for mounting on the RC:

OktoPussy first Flights

2009-02-05T04:19:00.000-08:00

Very early Flights of the OktoPussy ( the maiden flight got lost in some bad SD-Card ).

OktoPussy first Outdoor flight from ligi on Vimeo.

Specs:
- Frame ( Design & Construction by seba aka SelectaT )
- FC 1.0 ( green -soldered by Ligi) with Flight-Ctrl_MEGA644_V0_72a_Octo.hex
- 8*Bl-Ctrl 1.2 ( green soldered by Ligi)
- 4* robbe roxxy 2824-34
- 4* esky 002b
- 8x EPP1045
- 1x2100mah 3s Lipo
- lots of wires
- take-off weight ~1200g

OktoPussy from ligi on Vimeo.

Detail Pics:

DUBwise Range Extender

2009-02-04T05:03:00.000-08:00

Finally i had some time for a Project which was in my mind a long time - the DUBwise Range extender.

The Bluetooth Modules in Mobile Phones are very limited in Range ( for reasons of power consumption and size) - which is OK for normal usage of Mobile Phones but was a problem for some use-cases of DUBwise.
The range extender is a little box for the jacket which contains one Zigbee-Pro module ; a Bluetooth Module and power supply. Zigbee and BT are crossed ( rx=>tx ; tx=>rx ).

Now I connect to the BT module in my jacket with the Mobile Phone ( which is <10m in range normaly ) and the (long) distance to the MikroKopter is Made by a ZigBee Pro connection. ( specifyed range ideally by 1mile / 1.6 km )

Beside the range there is one more advantage. I can leave ZigBee on the MK permanently - I dont have to switch between Bluetooth for DUBwise usage and ZigBee for Riddim ...

QuadKopter Sunday

2008-03-31T05:45:00.000-07:00

3 * MikroKopter @ Sunday in LE
from left to right:
seba's LIFEKopter , Devlins Kopter , my CampKopter

new 4 BL-Ctrl's

2008-04-02T06:07:00.000-07:00

I had to solder 4 new BL-Ctrl's for my UAVP-NG and other QuadroKopter experiments:

3 worked out of the Box - one has a problem - the shunt always burns when i power up with firmware 0.41. ( exact problem in german here: http://forum.mikrokopter.de/topic-3946.html )

new DUBwise banner

2008-04-02T07:04:00.000-07:00

Im not an expert in GFX - but i have played with Gimp a bit to get an better DUBwise Banner:

btw. there are now over 4000 Downloads for DUBwise on GetJar !-)

4. BLCTRL workin

2008-04-05T03:55:00.000-07:00

So i hot-fixed the 4. BLCTRL ( 2 FETs where broken ) - The Shunt is not OK yet ( i have seen that i have the wrong equipment to measure the Shunt - can't measure weather Ohm or Aps in the needed ranges ...)

Android Developer Challenge Submission

2008-04-14T18:59:00.000-07:00

I submitted the Android Port of DUBwise to the Android Developer Challenge:

I wonder how "some time" is defined - I want to kow how they react ;-)
There are some mistakes in the PDF and in the app I submitted but i had to submit before deadline to be save - i had no deadline time info since the nice Timeout-Display on anddev.org broke with the site ( I get Forbidden Err) but i hope the Concept counts

Nice Go Game

2008-04-15T08:20:00.000-07:00

This is the game i played against seba after ~ 2 Days of no food much coffee and just a bit of sleep - but it worked pretty good ( i'm black as usual )

DUBwise for Android SDK 0.9-r1

2008-08-19T04:41:00.000-07:00

I stopped working on DUBwise for Android while they kept the actual SDK secret under NDA's. Yesterday Google finally released Android SDK 0.9-r1. So i checked if the old DUBwise version could be installed on the new SDK and it didnt work - nothing else was to expect ;-) Compiling with the new SDK was blocked by 31 Errors resulting in API-Changes ( e.g. Bitmap.width() => Bitmap.getWith() ) - I fixed those Errors and then I ran into singing-issues - which could be fixxed by creating a new build.xml via activityCreator.py.
So finally DUBwise is running with the new SDK:

aerial photography

2008-08-13T16:16:00.000-07:00

I've made some aerial photographs the last days.

Some more are shown here.
I also started a wiki page to describe the method I used ( and provide space for other methods ) to trigger the camera.

Video: AN-72 Boogie Cochstedt 2008 - Mikrokopter Perspective

2008-08-05T05:38:00.000-07:00

Some impressions from the AN-72 Boogie, including onboard footage from a Mikrokopter. Featuring Bird Men briefings on the ground, in-plane view of exit, skydivers landing, visitors, planes (Antonov AN-28 and PINK Skyvan), and some in-plane views of the exit. A great day for all of us!

P.S. the AN-72 got stuck in Moldavia...

Video-editing by Katja the ChiliFarmer with Blender & Gimp
Camera: Kodak Z1275

Thanx to Axel from crazy-skydiving for invitation & support !-)

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Germany License.

Video: First Flight of my Second MikroKopter

2008-08-03T11:21:00.000-07:00

Now I have a new MikroKopter for Beta-Testing , Rushing around and simply having fun. My CampKopter will be a Camera Kopter for slow flights from now on.