Archive for July 2007
The internet can be a terrible thing for people like myself with painfully short attention spans. I’ve acquired this nasty habit of finding something new and exciting on the interwebs and clicking the buy button without knowing precisely what it is that I’ve just purchased.
This happened to me a couple of months ago when I picked up a copy of the RFID Toys kit. Don’t get me wrong, the book came highly recommended and the author is a staple in the hacking community. What I didn’t know was that several projects in the book would require a Parallax Basic Stamp to complete. And while I don’t have any specific reasons for not wanting a Basic Stamp, I just don’t want one.
So this RFID Toys kit has been sitting around my house collecting dust for a couple of months now when I decided that it would be more fun, more interesting, and more educational if I were to complete the RFID Toys projects by interfacing the Phidgets RFID reader to my Arduino board. I have not seen this done so far, only links for interfacing the Arduino to the Parallax RFID module.
This is one of the projects that I will be undertaking over the coming weeks.
Normally I like to keep a Development journal of all the lessons learned, trials and errors, and general mishaps that take place when I begin working on a new project.
For BongoPong there isn’t really much to say.
The Velleman Pong kit was (one of?) the first kit(s) that I ever soldered together. It was a fun little kit to build, but I wanted more from it. I knew that I would someday find a fun or interesting mod for it.
A couple of weeks ago I came across an article on HackADay where a clever young hacker controlled his pong kit by flexing his own muscles. That hack got me thinking about new ways to interface with the oldest video game.
Being the worlds first video game, pong has been hacked to death. There are laser pong hacks, pong that plays against itself, and even pong on the side of buildings.
Clearly, finding something new and interesting in this saturated field would not be an easy task.
The ideas floated around my head for about a week. All of them were interesting, but each suffered the same flaw. They’d been done to death. Not necessarily with pong, but with video games in general. I needed to put a fresh twist on the old game. More importantly, it needed to be simple. My meager background in electronics certainly wouldn’t enable to run right out and build a mind controlled pong game.
The idea to use an Indo (Bongo) board for pong came out of the clear blue sky. Really. I have no idea what prompted me to think about it, I was driving when I thought of it. Within the hour I was at the hardware store, trying to find parts to make a tilt activated switch.
Things just kind of came together from there. I found the metal cylinders (see previous post), some PVC pipe, and a three foot piece of wood that looked sturdy enough to hold me.
The whole thing was functional in another hour or so. I was pretty terrible on the board that first night, and i noticed that whenever I would make a quick motion and the board would move very quickly to the left or right, the tilt switches would not react properly.
A quick google search taught me that this is a common problem, even for commercial mercury-based tilt switches. There is simply no way for the switch to differentiate between gravity and g-force. It makes sense when you stop and think about it. Luckily the problem became less apparent as I got better at using the board and the movements became more fluid.
The major flaw in my design was that there was no way to serve the ball without the controller. Using the Velleman pong kit, you serve the ball by pressing both buttons simultaneously. To fix this, I grabbed a cheap skateboard. Skateboards have the nose and tail curved upward slightly at the ends. I swapped the switches on the left and right side of the board, and flipped them so the trigger faced inward, and slightly down. This resulted in the same functionality as before, but now when the board is roughly parallel with the ground, both switches are activated and the ball is served without any additional user input.
As always, there are a million things I could do to make the project better. Imagine using an accelerometer to get analog values and then interfacing the board with a console or PC to play games like SSX, or even breakout.
It’s interesting to point out that I lost my entire weekend playing this game. At no point did I stop because I was tired and/or bored. Each gaming session ended when something on the board broke. On the first night one of the wires snapped off of a tilt switch. On the second night the PVC pipe cracked. I’d like to get a real Indo board, but the prices start at around $80 and work their way up. That just seems too expensive for a piece of wood and a rubber coated roller.
Be sure to check out the BongoPong project site for videos of BongoPong in action.
My latest project, BongoPong, is an entirely new (I think) form of interactive gaming that forces players to really get off the couch and into the game.
Check the BongoPong project page for more details and videos galore.
I started working on my next project tonight and realized that I needed four tilt activated switches. I wasn’t exactly sure what would make a good tilt switch. The majority of online videos and tutorials for tilt switches were either undocumented, mercury based, or actually accelerometers. Luckily I found these small steel hooyahs. I have no idea what they were actually designed for, but they make pretty handy little switches.
So, now I’ve decided to try my hand at this online video craze that’s leaving me behind, so peep the video for a simple demonstration of the tilt switches and try not to be too harsh.
Frequently Asked Questions:
Q. What kind of device did you use for USB communication?
A. The module that I used for the prototype is a pre-programmed Delcom USB chip. They are standard Cypress USB controllers that have been pre-loaded with firmware from Delcom. For the purpose of prototyping, I used a simple USB Interface Board, which is available from Electronix Express.
Q. Did you create the USB device drivers from scratch?
A. No, the drivers, along with sample source code for multiple programming languages, are available for Windows, and Mac OS X. There are several drivers for Linux available on SourceForge [here, here, and here].
Q. Do you mind if I port your code to another platform?
A. Not at all. The entire project will be open source very soon. I have not released the source code yet because it is embarassingly poor quality at the moment. I am actively seeking people to assist me in writing code. Please email me if you would like to help.
Q. Can I see the schematics?
A. Of course! The schematics will also be open source; just as soon as I make them. I designed this project by piecing together parts of different projects. So no real schematic exists at this time. I spent the entire day last Sunday completing tutorials on gEDA and Eagle CAD. Hopefully I will have a schematic to show soon. I am still a beginner in electronics, so I’m actually learning all of this myself as I go along!
Q. Do you have a timeframe for completion?
A. No, I’m sorry. I have a full time job, and I attend university full time. I will work on TrafficStop as much as my schedule allows. That said, the best way to motivate me is to email me and tell me how much you enjoy the project! Knowing that people are out there waiting for me inspires me to move forward.
Q. Have you considered selling this?
A. The thought has crossed my mind. I did a little research earlier this week, trying to get a feel for how much it would cost me to get this off the ground. I am thinking about offering a kit with custom PCB and required comonents so that you could assemble the stoplight quickly yourself. If you would be interested in purchasing this as a kit, please let me know.
Q. How much did it cost you to build?
A. Too much. I built the prototype using anything I could get my hands on quickly. In some cases this worked out to be a cheaper solution, but not always. I estimate that if I were to build another one today it would cost me around $35. That’s including $20 for the original blinking traffic light on which the project is based. It would cost much less if I were buying the parts by the hundreds.
