Happy Robot Labs

From Friday, Jan 27 to Sunday, Jan 29 a few of my friends and I spent a lot of time at Artisan's Asylum in Somerville, MA. We weren't there just for fun (though we had plenty of fun). Instead we were there to design a working RC hovercraft in 48 hours. The participants from BUILDS (BU's hackerspace) were divided up into two teams:

Team McFly and the Hoverboard: Christopher Woodall (me), Ian Felder, Marc Beneck and Alejandro Bancalari

The Cult of the Devouring Fan and Brogle the Insatiable: Russel Shomberg, Patrick Ehrlicher, William Gullotta and Alex Whittemore

In the beginning we were given the electronics, a piece of pink foam, some wood and access to most of the tools in Artisan's Asylum. There is no real documentation from either my group's design, or the other BUILDS group's design; however we certainly had a ton of fun and we have pictures and videos. Also, it was my first time helping design a Radio Controlled vehicle and it was a ton of fun (which I hope to do again).

Overview

This is just a basic little dynamo which uses a tiny 6V DC motor I scavenged from an old CD drive. I have grander plans for the motor in the future, but I thought it would be cool to use it to turn on an LED with it!

The basic idea is pretty straight forward. If you take a motor, which has a permanent magnet in it, and turn the magnet on your own you will change the magnetic flux in the coil and as such start generating some current and, you will start to get a potential difference building up across the terminals of the motor. If I knew the RPM rating of the motor then I could figure out how fast to turn it to get a full 6 Volts. At the moment all I know is that I need to spin it pretty fast and the peak value my multimeter reads is 2.5 V, which is enough to power an LED.

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Overview

Nomis is a Simon-like memory game for the ATTiny85, which uses the ATTiny85. The game logic in the ATTiny85 was implemented using AVR C and takes up 983 bytes in program memory and 6 bytes in data memory. The implementation size comes in under 1kB, but could most certainly be smaller. The pin usage, however, is very conservative and the games electronics take up a total of 4 of the 6 available pins. The 4 LEDs are controlled on 3 pins using Charlieplexing model (which could easily be extended to 6 LEDs). On the other hand the 4 pushbutton switches are feed into an ADC input through an R2R ladder configuration. I am very happy with the limited pin usage of this project.

The gameplay of Nomis is the same basic scheme as Simon. Which is to say once you initiate a game with it the game logic generates a random move, which lights up one of the 4 LEDs. Then Nomis waits for you to copy it. Each consecutive move is stored in an array and the string of moves must be copied exactly by the player. The game has no real ending conditions; however, the maximum number of moves is 100, but even then that limit was arbitrarily set by me. With a sufficiently large slice of memory and an extremely skilled (or cheat prone) individual the game could last forever. That said, the goal of the game is to best your previous score, which you keep track of by yourself.

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I am putting together a color organ! Currently I do not have my schematics written up and I plan on making an in depth writeup when I get closer to being done. However, I did record a video of its current status!. I also have a photo dump on flickr.

The plan for the final project is to have the three filters (which need to be cleaned up), running into an RGB LED and controlling the different colors. I was thinking about shooting the produced light through a piece of sanded acrylic and try to get a nice effect that way.

I attempted to make conductive paint, for the BUILDS room. The end goal is to have conductive paint, which can be painted into the murals being put up in BUILDS and as such we can make the room interactive using capacitive touch sensors. Just to note this is not the final product this was just a test run. So far the best result I have is 1k?

Conductive Paint is a conductive material made up of a conductive powder suspended in a binding fluid. When dried the conductive powders will be close enough together that the material itself becomes conductive. There are different kinds of Conductive Paints, but the easiest and cheapest to produce utilizes graphite powder. Carbon Graphite is a surprisingly good conductor and is both easy to come by (as it is often used as a lubricant) and relatively easy to work with and mix into other materials. Most of my resources for this first attempt came from this awesome Instructables created by mikey77.

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I recently decided to do some development for the ATTiny85s I have laying around. I added a few of these to a Sparkfun order about a year ago to use up my Free Day money, but since I forgot about them and moved on to other electronics pursuits. However, I finally decided to start programming them and at the same time I decided to improve my prototyping skills, develop a really nice development board for them, and learn KiCAD.

The current version works and I was able to program my ATTiny85 using my Pololu AVRISP v2 Programmer and Arduino 1.0. I was able to program using Arduino thanks to the High-Low Tech Lab over at the MIT Media Lab. While I plan on programming these microcontrollers using C, my familiarity with Arduino allowed me to rapidly test my design and make sure that everything loads up onto the microcontroller just right.

More video and coverage coming later!

Links:

• KiCAD Source Files of Github
• Pictures on Flickr

This weekend I decided to get some work in on learning KiCAD. I have not come very far, but I am starting to get oriented with eeschema and I have actually been enjoying it. However, I had to boot up into Ubuntu to work with it appropriately, because my Mac OS X install doesn’t quite like KiCAD, but then again I have trouble with Xilinx, iverilog, gtkwave, msp430-gcc, etc as well.

KiCAD works very smoothly for the most part with a couple of interfacing hitches. Namely you need to ctrl-drag to move multiple components, which took me far too long to figure out. Furthermore, I am not a fan of the built in library symbols for power, ground or the connectors. However, I don’t mind this so much because I am not completely opposed to making my own libraries, which will be uploaded to github, when I get a chance and open to all.

I really enjoy the way KiCAD works and the fact that it is open source, unlike EAGLE, and has no restrictions on it. Between work and past hobbyist work I have been exposed to Orcad Capture, EAGLE and EasyPCB/EasySCH. Orcad, though complicated, was my favorite of those schematic layout tools. The reason is that it has powerful hierarchies (I was doing large layouts) and very nice component making utilities, also there is a separation between the schematic phase and the PCB phase, which allows you to think about the actual functionality of the circuit during layout and the topology during PCB design. KiCAD follows a similar rule for schematic to PCB layout from what I can tell (more to come on this).

I would recommend KiCAD to anyone looking to do some schematic layout for free, with no restrictions.

Happy Hacking!

I have been using MIDI for quite some while now to communicate musical instrument based projects to my computer and visa-verse. My first MIDI project died, somehow and I never quite figured out how; however, before my MIDI Ribbon Controller died I was running into some troubles with MIDI. The base trouble stemmed from MIDI’s roots as a 1982 protocol for digital music communications to allow musicians the ability to mix different synths from different vendors, without needing complicated and expensive adapters. By nature MIDI is a slow, backwards compatible standard (which is what it needs to be), with rigid note structures. This means that doing sliding motions without well defined notes is actually quite difficult, because MIDI simply cant send different notes fast enough. Also, delay starts to become noticeably because the baud rate is rather slow.

So what is one to do? MIDI is still the industry standard and that doesn’t stand to change very soon. However, for personal projects there is a new standard which is starting to come into common use. Furthermore, it is faster, and more flexible than MIDI and just as open. This is OSC, Open Sound Control, and its been around for awhile, but it is really picking up speed in the realm of experimental music controllers. For example, Lemur is using it and so do a lot of Monomes. But what about the software, that’s very important too! Well Reaktor is OSC compatible and so are Max/MSP, Ardour, Logic Pro, Overtone (that Clojure based music programming language), Pure, Processing and Traktor. So the software support is there.

There is a need for a move forward for the day to day experimental music control interface hobbyist/experimenter and I plan on diving into OSC and writing more up on it. If you have some tips or tricks feel free to contact me!