Documentation

Affordable Sound Both for Voice Recording

Posted by on Sep 1, 2017 in Design, Documentation | 0 comments

Affordable Sound Both for Voice Recording

Recording a clear voice with no background noise is key for any video, audiobook or podcast. If you are limited in space and budget then you might consider building your own little sound proof voice recording box. I build this little gem from 6mm MDF and some acoustic foam taped to the box with double sided tape.

For the box you can create the drawing necessary for the laser cutter using online tools, such as Box Designer. It exports a PDF file which all the six faces clearly separated. If you are planning to make efficient use of your wood then you may prefer MakerCase. This service aligns the six sides so that they can be cut most efficiently from a piece of MDF. Here is the box drawing for laser cutter used for this design.

We attached rubber feed to the box and placed the microphone on an old mouse pad to isolate the microphone from any vibrations of the table, such as when a laptop is placed on it. Handles on the side allow for an easy transportation.

Here is a recording without the box. The microphone was placed just directly on the table:

This recording was made with the speaker sitting in front of the box speaking into the microphone.

The last example is with the speaker leaning into the box.

You will notice how all ambient noice is gone and how intimate the voice of the speaker sounds.

Read More

Tutorial on how to install and setup JInput on Mac OS X using Eclipse

Posted by on Aug 14, 2017 in Documentation, Technology | 0 comments

Using mouse, keyboard, joysticks and other input devices in your Java software is much easier using JInput. Unfortunately, the documentation on how to install and setup the software is short and difficult to follow. I was struggling for days getting it to work with Eclipse on Mac OS X 10.12.6. My first approach was to use Maven to install JInput. The excellent M2Eclipse plugin provides good support for Maven. Unfortunately, the pre-configured Maven Repository does not include JInput. I was unable to configure Maven/Eclipse to connect to The Central Repository to download JInput from there. Okay, I am not a fulltime Jave programmer and maybe it would become clear to me eventually. In the meantime I got it to work manually. I hope that this tutorial will help you in your project. I used Mac OS X and I cannot guarantee it will work on any other platform.

Read More

3D LEGO Technic Connector

Posted by on Jul 29, 2017 in Design, Documentation, LEGO | 0 comments

Connecting LEGO Technic beams in three dimensions remains a difficult task. While it has become easy to connect beams in one and two dimensions, it remains difficult to extend this to the third dimension.

I first designed a new LEGO Technic connector that features pins. The design was compact and stable, put the pins were too fragile. It was also very difficult to get the support material out from the holes.

My second design had no pins but still the option to firmly hold a technic beam. With this new 3D printed corner part it is possible to build a perfectly stable cube with a minimum of parts. The additional holes provide options for further strengthening the cube or to connect other parts to the cube.

The CAD model is available from Autodesk and GrabCAD.

 

 

Read More

TicTacToe Playing LEGO Mindstorms Robot Using Computer Vision

Posted by on Jul 17, 2017 in Documentation, Featured, LEGO, Project | 3 comments

TicTacToe Playing LEGO Mindstorms Robot Using Computer Vision

You can play TicTacToe with this LEGO Mindstorms EV3 robot. It uses three motors to drop the balls into the right field. It uses a NXTCam to view the board and then calculates the best move using a MiniMax Algorithm. All future moves are explored an rated according to their winning chances. The work is based on the TicTacToe code of Thomas Kaffka. An IR sensor detects your hand when you drop your ball. The robot is using red balls and the human player uses blue balls. The Java code is available over at Github. The building instructions are available for LEGO Digital Designer. I used the MinuteBot baseplate, which is useful for building static Technic/Mindstorms models.

 

LDD does not have all the required pars in its database. You will have to replace 22961 with 27940. You will also need to add a worm wheel 27938. In addition you should use a lamp to provide consistent lighting. I used a USB powered LED circular lamp the can be powered through the USB port of the EV3. I only had to take out the lens in the middle so that the camera fits through the hole. A rubber band holds the light in place. To calibrate the robot I added a little arm at the end of the base plate against which the robot arm rotates. The position of the camera can be centered on the board using the wrench and through sliding along the axles.

You can also find information about the robot over at Rebrickable. The inventory there is correct and complete. Except for the base plate of course.

 

Read More

Using your LEGO Mindstorms RCX on a modern computer

Posted by on Jun 8, 2017 in Documentation, LEGO | 0 comments

Bringing back your old LEGO Mindstorms RCX to life is easier than you might expect. The bottleneck is being able to communicate with the RCX using the Infrared Communication Tower. Version 1 used a tower that was attached to the computer using the old serial port (RS232) while version 2 used a USB tower. The later is much easier to use these days since most computers still have plugs that are compatible with USB1.1. For this tutorial you will need:

We will setup a virtual machine on your host computer (Mac or PC) and install Windows XP on it. We will then install the original Robotic Invention System (RIS) so that the USB driver is correctly installed. You can then use RIS to program you RCX or you can setup many other programming environments/languages. Another problem you might encounter is that the cables used to connect the sensor and actuators to the RCX have become brittle and the isolation comes off easily. You can still buy some new cables from Bricklink.

Read More

Tutorial on how to install and run Java on Lego Mindstorms EV3 using Eclipse on Mac OS X

Posted by on Jun 4, 2017 in Documentation, Technology | 0 comments

We will be installing Java and the Eclipse Integrated Development Environment (IDE). This will allow us to develop your LEGO Minstorms EV3 software in Java and running it on the EV3 using LeJoS. Please let me know in the comments if you encounter any problems. I will try to keep this tutorial up to date.

You will need:

This tutorial will only get you started and you might want to dive much deeper into Java development for the EV3. These books might be useful for you:

My personal favourite for building amazing mechanism is Sariel’s book:

Read More