Arduino Punk Console 8 Step Sequencer

The arduino punk console is a simple tone generator that is capable of making some cool audio sequences. I've always enjoyed playing around with different audio equipment (see my analog synthesizer here & here) and this looked like a cool project when I saw it on the Make Blog. It is a fairly straightforward project that uses an arduino to handle all of the switch and potentiometer inputs and generate the tones. What is especially fantastic about this is the flexibility afforded by having a reprogrammable controller instead of a hard-wired sound generator. That said I haven't modified the original code yet.

While the original project was good, I made the following changes for my version of the arduino punk console:

1. Eliminate the LCD screen - I wanted to make my version as cheap as possible and I thought the LCD was somewhat unnecessary for a simple project such as this since it doesn't display very valuable information. 
2. Scratch build the arduino board - Similar to other DIY arduinos (see here & here) I've done before based off of the Boarduino design, I had the parts and building it myself cut the cost of the unit.
3. 9V AC adapter power - I have found it is much more convenient to power many of my projects with an AC adapter instead of batteries as it saves having to access the inside of the unit for battery replacement and the portability provided by battery power is rarely necessary.
4. Substitute 5K ohm potentiometers - I'm not sure why the original project used 100k ohm potentiometers, but I had a bunch of 5k's around and they worked fine.
5. No speaker - I was planning on using an external amplifier so I replaced the speaker with a mono 1/8" audio jack.
6. Eliminate the volume control potentiometer - Again, because I am using an external amplifier I don't need another volume control.

Check out the video below of the sequencer in action: