Artisan's Asylum Hovercraft Competition

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).

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.

Continue reading Nomis: A Simon Clone for the ATTiny85

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.

Continue reading DIY Conductive Paint Attempt 1: Proof of Concept

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!


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!

Projects: Reload-JS (v0.1)

Reload-JS is a javascript live loader whose goal is to be simple and light weight. I created Reload-JS while working on an Infographics Landing Page, and embedding solution, for Newlogic USA. I needed to load and check for any libraries I need (namely jQuery). The loading part has been taken care of in this version, but I am trying to figure out how to include tests for each library, to make sure no override occurs (my jQuery doesn’t break or overwrite the loaded pages jQuery).

More after the jump.

Here is the Reload-JS source code. It is simple and it doesn’t really do anything special. Most of the code has been used previously and is very popular for live loading. It accomplishes its task by using a recursive set of callbacks and has a few ways to call it.

First you can use the following:

Or this

My personal favorite is this following call:

You see Reload will automatically append the js if you don’t already have it attached. This is a nice feature to make nice simple calls like above. Reload allows you to set your primary library location and then takes care of it too. This makes loading multiple libraries pretty nice. However, what if you need to use a different host for one of your libraries? No worries! just make sure you use http:// and Reload will detect that it shouldn’t append your default library location to your URL (absolute URL handling).

Reload also has the ability to load from a variable it holds called libs. This can be risky, if multiple people try to use it and is not suggested unless you are sure no one else is using Reload.

Here is the code (and decently commented):