Inter-space (re)build: Asteroids

Long ago in a space far, far away, the Quelab crew had a means of amusement: Asteroids.

A donation from Adric, the Asteroids cabinet has seen its fair share of hands across its buttons: life at, presumably, an arcade and then later at Southwest Cyberport, it was brought to Quelab after it just didn’t have any more go in it. Never one to give up, we replaced the required parts, added a high score save kit, and pounded out more hours on it, racking up high scores in the 15,000 range. Some time later, we moved, and the cabinet stayed dormant: Nobody really wanted to play it much anymore. The buttons had been abused and left in a sorried state, dust had crept in, and the final straw came when a known issue with contact corrosion had made the board unable to boot again.

That is, until someone decided to fix it. Morgan G. (myself) and Ben L (of Black Lodge Research in Redmond, WA) decided to dig in and, over a weekend, get the thing up and going properly. Some preliminary work had gone into getting it working again.

So, what needed to happen? Just some cleanup, love, and a bit of attention. New fuses, cleaned contacts, and lots of reading schematics later made it clear what the problem was, and some new features we could add in for fun, and a beautiful, well-loved cabinet was given new life.

We left a note to anyone who opens the cabinet up in the future, as well as a copy of the manual, reproduced in true Atari form, plus some spare parts.

The root cause of the cabinet not working is a well-documented flaw in power supplies that use a sense line: the sense line needs to be really good in order for the whole thing to work, and if it isn’t, there’s a good chance the PSU will just cause problems. In an ideal world, they’re self-regulating; From an EDN article on the topic:

The remote sense function automatically increases the output voltage at the output terminals of the supply to compensate for any unwanted voltage drop in the output cables with heavy load currents. Likewise, the remote sense function decreases the output voltage of the supply when the required load current is reduced. In some applications, the power supply’s output needs to be adjusted by the user to voltage higher than its nominal (e.g. 5V nominal, adjusted to 5.5V). Always adjust the power supply’s output while measuring the voltage at the load.

The EDN article concludes saying these are only really useful in extremely high load environments (read: not the environment that Atari had been building for) and should be avoided in newer designs. Perfectly reasonable in Atari’s days, but we’ve learned new things about how the world works. It’s bad enough that bypass hardware exists for these since a bad sense line can cause insane voltages (40-80V!) when they go bad.

Getting started with the STM32F4Discovery 1

If you follow the Hack-A-Day stream, you’ve probably seen the STM32F0Discovery board come up on occasion. I have two of these boards and I like them — they have what I need for basic stuff, but I wanted some more horse-power (and USB Host.) Quickly, to the STM32F4Discovery!

The target here is people who’ve outgrown the world of AVR and need something running faster; you should be capable and comfortable with diving into your PATH, mucking with environment variables and reading some pretty deep C.

STM32F4 Discovery board (From ST)

STM32F4 Discovery (From ST)

I was given one of these for xmas a little while back (read: 8 months ago) and played with it, getting demo code to run on it. ST did something very painful and/or clever in that they produced this board, for hobbyists, but conveniently forgot to point to a clean, unadulterated compiler.


Calling All Musicians! 3

bottlecap contact microphones

Circuit-Bending Hackerspace Rock Band, CMKT 4, is doing a workshop Wednesday, May 9th, 7-9:PM building contact microphones in conjunction with Quelab. These microphones are powerful enough to do whatever you want, and accessible enough for all skill levels. Plus, they’re made out of bottle caps, which is just awesome. It’s a DIY electronics project that leaves you ready to do other projects, too. Register at any hacknight or through Eventbrite.

Workshop attendees will learn how to solder/improve existing soldering skills, work with recycled materials, and develop a basic understanding of piezoelectricity. The process involves a 45 minute dry-time, during which CMK4 will entertain the workshop attendees with a live performance. Additional kits and microphones will be available for purchase, as well.

There will be a separate members-only event later in May. If you’re interested, please contact us about details!

See them in action on YouTube.


Photos from the workshop can be seen here, And Wookie (Ready handed Media) took some video.)

Peggy 2LE 3

This is what I'm making

(Image via Flickr/oskay)

Early last year, I got involved in the planning stages of Quelab because I liked the idea of having a coworking space in Albuquerque. While I’m still mostly involved with the coworking side of Quelab, hanging around people putting together great projects for the last few months has been inspiring, so I decided make something of my own for LED night. I picked up a Peggy 2LE kit from Evil Mad Scientist Laboratories. If it works properly, I should be able to make it do cool things like this when it’s done. But that’s a big if: this project involves lots of soldering (there are 625 LEDs alone) and I have very little experience soldering. It’s a little intimidating, but I’m the type of person that likes to dive off the deep end. In any case, I’m sure it will be a good learning experience. I’ll be working on it on Sunday’s Hacknight. Feel free to come on down and give me some moral support or, better yet, some pointers on soldering.

Player Piano Roll Reader Project 8

I have about 50 player piano rolls (exactly why I have 50 piano rolls is another story).  Despite the fact that most of the rolls are about 80 to 90 years old they are in surprisingly good condition.  However, I do not have a player piano to play the rolls on.

In this part of the country (the Southwestern part of the US) player pianos are very rare so getting a player piano, much less having the room for a player piano, and investing the time and expense of repairing a 90 year old instrument, is not very likely.

Today in an average living room the television is the centerpiece of the room, followed by an entertainment console that usually houses a DVD player, a bunch of DVDs, and maybe a gaming system.  In the 1920’s when most of these rolls were manufactured, there of course wasn’t television, DVD players, or gaming systems, and commercial broadcast radio was still about 20 years away.  Records were available, but records sounded tinny and were rather expensive.  So what was “must have” the entertainment machine sitting in an average living room in the 1920’s?  Most often it was a piano and most of those pianos were player pianos.

Back then, piano rolls were like CDs are today.  All of the “Top 40” songs of the 1920’s were on pianos rolls.  But just like listening to CDs, sooner or later you get tired of the music and want something new.  Back then people would go to Sears Roebuck and buy piano rolls.  Families would often spend evenings together singing songs around the player piano.  Yes, I know. It sounds incredibly lame by today’s standards, but back then they didn’t have much else as far as entertainment in the home.  The player piano was pretty much the “in thing”.

In looking over the rolls I found such interesting titles as “I’d rather forget than forgive”, “I’m gonna let the bumble bee be”,  “Can I sleep in your barn tonight?” and a few with familiar titles like “I’m looking over a four leaf clover”.   I began to wonder what music might be on the rolls – Just what did “Top 40” sound like in 1928?  What secrets have these rolls kept hidden for the last 90 years?

I decided to find out.  On Ebay I purchased a player piano “spool box”.  This is the mechanism that reads the rolls in a player piano.  I wanted to find some way of converting the spool box into something that could extract the music on the roll and send that note information to a PC.  Then on the PC that information data could be converted to MIDI.  If all worked, I would be listening to music that few people have heard in nearly a century!

Well life often has other plans and I put off the Player Piano Roll Reader Project for another day.  It sat along with a number of other neglected projects for about 3 years until I discovered Quelab.  In discussing the project with several Quelab members, there was renewed interest.  These people wanted to hear what was on these rolls as much as I did and the idea of converting 90-year-old digital information to MIDI seemed pretty cool too.

90-Year-Old Digital Data

So the basic plan is this: Put a bunch of infrared LEDs on one side of the roll and 88 light sensors on the other side of the roll and read the data from the sensors.  I chose infrared LEDs because paper is mostly opaque to IR while visible light pretty much goes straight through.

Infrared Light Bar – 50 IR LEDs Closely Spaced Together

Since the “read holes” in the spool box are too small for commonly available IR sensors, I will be using fiber optic cable to transmit the infrared signal from each hole in the roll to IR sensors on a separate circuit board.

IR Output From the Infrared Light Bar

I used my cell phone camera to capture the IR output of the light bar.  Although it is hard to see in the picture, all of the LEDs put out a strong IR signal.

The next step is to order the fiber optic cable and start building the IR sensor board.  This will be 88 IR light sensors connected to 88 fiber optic cables.

See Part 2