While I was busy saying that my sequencer helped make the SX-150 into more of a viable sound-making tool, this guy was making an ass out of me.

Ok, so that was a couple years ago, but it's still awesome, and it's great to see the SX-150 being used as a real instrument. I still think it's pretty hard to control with just the stylus and a sequencer gives you more to work with, but this is pretty awesome.

This is the big one. Following up on Part 1 -- where we took control of the SX-150 pitch control, and Part 2 -- where we built on that to have basic sequencer note-on/note-off control, Part 3 is where it comes together with a hardware-and-Arduino based 4-step sequencer for the SX-150!

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[Update: This article has been continued with Part 3]

Back again with the next phase in the Arduino-based sequencer for the SX-150 project. Boy, I need a catchier name for that. I'll work on that.

If you recall, at the end of Part 1 I had used a digital potentiometer to replace the stylus-and-strip control for the Gakken SX-150 Analog Synthesizer.

In this next stage of the project, I'm going to replace the digipot with one that has a wider range, then extend my circuit and my source code to let the arduino directly play individual notes without having to worry about resistance values.

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This seemed worth coming back to since it was buried at the bottom of my "Using the 555 timer as an external clock for the Arduino" article, but I have built a calculator for oscillator timing with the 555.

I know, I know, there are a lot of those out there. Well, that's half true. There are a lot of calculators that will take the resistor & capacitor values and tell you what the resultant timing would be... but usually you start from the other direction... you have a timing spec in mind and you need to know what components to use. That's how I tackled it.

You tell it that you want the timer to fire every 60 seconds, or at a frequency of 440Hz, and it will make recommendations about some common components that will have that effect, along with duty cycle, etc.

Because my blog software doesn't like adding javascript very much, I put the calculator on it's own separate page: http://totusterra.com/555timercalc.html

Hopefully this will be useful to anyone playing with the 555, with or without the Arduino involved.

[Update: This article has been continued with Part 2 & Part 3]

Out of the gate with the first blog post of the new year, and this is one I'm particularly excited about because it gets me to the point of starting to hack things that make cool sounds. I've long had an interest in experimental electronic music, so I'm excited that I have something to share in that arena.

In the past I've mentioned my wonderful wife (who is wonderful, if I didn't say so), and this Christmas she doubly earned that distinction by buying me a Gakken SX-150 Analog Synthesizer. As far as a 'kit' goes, it isn't much to speak of -- just installing the pre-built board* and speaker into the plastic case and wiring up the stylus controller -- but it is such a simple design that it seems built to be hacked on, and that's what I wanted to do.

I did find a number of cool SX-150 hacks, but often they were a bit more advanced than I'm ready for, so I figured I'd start with something simple and slowly build on it and make this a multi-part project. Since I'm really enjoying getting into Arduino programming, an Arduino-based sequencer seemed like a good candidate -- so let's get started with part 1!

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