Nomis: A Simon Clone for the ATTiny85


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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Color Organ Prototype 1

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.

DIY Conductive Paint Attempt 1: Proof of Concept

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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ATTiny85 Development Board (Rev. A)

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!


KiCAD: First Impressions

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!

Controlling Music: Look Forward To OSC!

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!

Lessons Learned: Breadboards are Noisy and So Are Those 7400s

While building my 7400 drum machine for Dangerous Prototypes’ 7400 Competition I made a couple of good discoveries:

  • Those pre cut jumper wires which are very popular (the wiggly ones) are a blessing and a curse. For one they make things look messy, but they are easy to prototype with. However, their biggest negative is sometimes, combined with a breadboard, they can give noisy connections. However, these wires are awesome for prototyping! Example

  • Breadboards are noisy… I already knew this, but this project has confirmed it. While I very rarely actually get issues from the noise, it can be very frustrating when I am prototyping various parts of the circuitry which are noise sensitive. Furthermore, 7400 ICs really need two things badly: a good ground connection and a stable Vcc connection. There is however an easy way to get around this problem, or at least reduce it and that is the infamous 0.1uF ceramic capacitor to ground. Make sure you put these on all of your VCC inputs and you will reduce error propagation in your digital logic circuits… and its good practice.

Now I go back to work!

Happy Hacking!

Drum Machine based on 7400 ICs

Dangerous Prototypes is having a competition based around building awesome projects using discrete logic components (7400, 4000) as a major part of the project. I had many ideas for submissions for this competition, for example, Pong (or another basic videogame), Game of Life, a real life color detector with readout to hex and an RGB LED. However, I decided on making a drum machine for this project.

I spent this weekend designing the overall project and constructing various parts of it. Currently I have the clock and Multiplexer both up and running and I am confident I can get the rest of the circuit running by October 21st.

Here is what the project currently looks like:

More pictures can be found here

My current schematics can be found on my github here.

More information about the competition can be found here.

Happy Hacking!