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Archive for the ‘Tecnologia’ Category

To make a film there is an open source software called Blender . It a 3d modelling tool with a timeline and you can change everything on each frame to obtain a story that progress with time. There are tons of step-by-step tutorial to all you want in blender.

For fun I did one of these and you can see it here. The result is not the best only because of my scarce ability. I used several specific tutorials to do it:

  1. modelling a terrain
  2. create on ocean and obtain water transparency
  3. create a palm tree
  4. learn character modelling

Then I used another open source tool, Audacity to record speeches and dialog. I used audacity filters for modify frequency of voices of different characters, so I could give my voice to all characters of the film. I could make the entire film only by myself !

 

Annunci

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Wikiknots is born

In 1999 I made the “alrama’ knots site” . Using VML (Vector Markup Language), a technology embedded in Internet Explorer, that site, on Tripod hosting service, allowed everyone to record a knot and see it among the others already recorded. Time passed, VML was dead, Tripod site was cleared , all passed on.

Now I decided to rebuild the very same features in a new site, using the standard technology web offer now, SVG supported in all modern browser. Much work is still to do but main features are already there:

  • grafical interface to build and record the knot
  • listing of the knots recorded
  • detail of specific knot with animated tying

Try it here: http://alrama.altervista.org/knots and let me know your comments !

catturacattura2

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es in multicast con frequenza 514000 khz con il programma 8583 e riproduzione locale

<path vlc>\vlc.exe  dvb-t://frequency=514000 –program=8583 :sout=#dup
licate{dst=udp{dst=239.255.1.1:1234,mux=ts},select=”program=8583″,dst=displ
ay,select=”program=8583″} :dvb-adapter=0 :live-caching=300 :bandwidth=0 –progra
ms=8583

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Public transports and private cars cannot often cover all the distance we need to do every day. So which is the best transport to do the last mile ? See some alternatives:

  1. bicycles and folding bicycles. Too heavy and uncomfortable to load and unload into cars, undergrounds and buses. We can’t arrive in office tired and sweaty too.
  2. (folding) e-bicycles. Same as above. No tired and sweaty problem here but they are too expensive , prices are 500€-1000€
  3. electric skateboards. They are light and fit very well to carry them in underground buses and cars. They are expensive yet (around 1000€) and only some young people fit well with them.

I thing the best solution is doing a good e-scooter. Actual e-scooters are too heavy with lead-technology batteries or are too expensive (1000€) because of too many components, but it could instead be:

  1. right for all people because of easy skill required
  2. easy to carry into all kind of private/public transport
  3. can cost under 200€ choosing the right build pattern

First two points are already done, see how reach the third.

Basic scooters weighing less than six kilograms, with wheels size of 20cm or more can be found on Amazon around 40€-60€ . In Italy, e-bicycles cannot have no more then 250W power motor. So this could be a sample configuration:

  1. A Brushless motor as motor: 200W Turnigy L2215J-900 (15€ on HobbyKing )
  2. an ESC (Electronic Speed Controller) as motorcontroller: The Turnigy TY-P1 25Amp ESC (12€ on HobbyKing as well)
  3. A (poly) lythium battery for its light and powerful features: Turnigy 1800mAh 3S 20C  (11€ , HK)
  4. a programmable board to manage the device: a Leonardo Arduino (5-10€ )  on ebay
  5. a bluetooth module to communicate between arduino and our smartphone, used as device control interface): HC-05 (5€ on ebay)

All the components costs 53€ plus 50€ for the scooter on amazon we are on 100€ . Then we have to consider the mechanical components. We need a chain or a belt for trasmission and some gears to transfer the power from the motor to the rear wheel. Gears and pulleys can be easy modeled with OpenSCAD and  then 3D printed. All the components can reach 120-150 € so we are on target.

This is a complete first prototype:

This prototype cannot carry none because of insufficient power trasmission between motor and wheel. The belt slet on gears when someone ride the scooter. So the real problem to solve, only because of my skill absence, is the power trasmission modelling and mechanical realization. I posted all detail here so someone can succeed where I failed.

Here a different gearing pattern tested, using conic couples:

20150505_220712

a components housing example:

20150507_211512

The Smartphone for control and display dashboard:

20150507_212000

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I found Standard Android SDK Emulator too slow (ARM images) or not jet reliable (Intel Atom images). Lucky we have an alternative in AndroidX86 images installed as VirtualBox virtual machines. These are simple instructions to setting up and integrate them with Eclipse Android SDK Environment.

1) Start installing AndroidX86 in VirtualBox as in http://www.fixedbyvonnie.com/2014/02/install-android-4-4-kitkat-windows-using-virtualbox . Choose ext3 to be able to write on SDCard emulated. In settings disable screen save timeout or remember to use “menu” key on PC to wake screen

2) on VirtualBox machine configuration set network as NAT and add a forward port rule on odd number port example: name=adb, protocol=TCP , host-port=5559, guest-port=5555 . After that Eclipse Android SDK adb automatically will connect on 5558/tcp port.

3) set your needed screen resolution as in http://stackoverflow.com/a/8273560/587323 . Editing menu.lst you can set your screen density adding the parameter DPI=213 (for example) on kernel line command

4) connect Eclipse for deploy, debug, ecc. From PC command line: adb connect localhost:5558 , then adb -s localhost:5558 root (to get root access from SDK DDMS) and again adb connect localhost:5558 (to reconnect in root mode)  restart adbd for complete root access: adb -s emulator-5558 root

5) You can switch screen resolution on-the-fly by adb shell commands: adb -s emulator-5558 shell wm  size 1280×800 , and density adb -s emulator-5558 shell wm density 189

Useful VirtualBox keyboard shortcuts:

  • CTRL+F1 : switch Android in Console mode
  • CTRL+F7 : switch back to Graphic mode
  • CTRL+F12: switch to portrait mode
  • CTRL+F9: switch back to landscape mode
  • CTRL+Menu: exit from Android Screensaver
  • CTRL+Home:  VirtualBox menu

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The “Gift Economy (reputation based)” android project is started ! Will you contribute ?

Motivation of the project is the manifesto exposed in article: “Is this money based economy the only our chance?” . Now I wish develop apps that make that kind of economy a real one. First step is to build a Free & Open Source (GPL v.2 license) Android app , compatible with all those smartphones & tablets. The Eclipse Android source project is live and public on GitHub.

The app will be totally Peer-to-peer and serverless to avoid any central administration or control of the data. The peer-to-peer technology chosen is Kademlia DHT ( BitTorrent and Emule) [reference for implementations: 1,2]. All the Reputations and testimonies made will have to be encrypted by a private key (same as Bitcoin does with his transactions) to avoid fake and/or massive span ones.

Here below you can see Use Cases and Classes Diagram to understand what we will get at the end of the project.

Feel free to join the project on github workplace !

registeruser

requestgood

requestgoodunavail

addtestimony

userchangesettings

ClassDiagram

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Object recognition by computer programs is the biggest promise of a endless range of new application and appliances (Internet of things) . Robotics, devices can be much more smart if they could be able to recognize objects viewed by a webcam.

So I experimented some software technics to reach this capability. In detail I concentrated into:

  1. finding points of interest in images and linking them by optimal triangles (Delaunay triangulation).
  2. Let users select which triangles best approximate the choosen object shape
  3. Using periferic points of selected triangles to find other instances of that object in different images or videos by mean of a “projection transform” (2D Homography) . I’ve still to do this but with main algorithm already made for this develop.

This picture is an example of first 2 steps:

ImageIf you wish directly experiment this function, below is the Flash app developed. You’ll have to:

  • accept webcam input
  • take image to elaborate pressing “Rileva” (Detect)
  • after few seconds you’ll have the points of interest on right side and, with right click on image, select “Vedi Aree” (Show Areas)

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