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Tag Archives: arduino
The Lowest-Fi Digital Delay
A little while ago, I built my own Lo-fi Arduino Guitar Pedal. I’m even using a similar enclosure – work tossed out a couple of thinwire->twisted pair converters that I snapped up. I think the only major deviation is that mine only has one output at present- I could add a second later, though.
I got to thinking last week that a digital delay would be an interesting idea – I had no notion that this would compete with anything in the quality department- a very short, crunchy delay – I just wanted to try it out.
So I wrote a little program and originally used an array of 512 values, and cycled through them, while recording point i, and playing point (i+1) (with edge checks and things like that, of course)
It turned out that 512 shorts of storage must have overflowed available program memory and caused general non-functionality. Changed the delay to 256 shorts. That at least got me up and running.
And it gave me about a second of delay time – kind of unexpected (that makes the sample rate, what, a few hundred Hertz?). It also doesn’t give a very accurate representation of the input. A test went something like this: snare (pause) krrrzzk.
audio: ArduinoDDL1.mp3
Once I commented out the #define DEBUG 1 line, it seems a lot happier 
There isn’t very much delay time, and it still gets really weird on occasion, but it does kind of do something to the input.
Here’s an example of it, with adjustments to the amount of delay and effect mix: ArduinoDDL2.mp3 – note that it gets loud and obnoxious in places.
Maybe better than the crappy plate reverb of a few weeks ago? Really, hotrodding my Realistic would be the best way to go for the all-DIY album. Probably not enough time for that, though – I’d really like to get it done soon.
If you’ve built a Lo-fi Arduino Guitar Pedal, get the code here: ArduinoDDL.zip. Knob A controls the delay time, and Knob B, when set to zero, should flush the audio buffer and blink the blue light while it’s doing it. Or it’ll just do weird stuff. YMMV – mine certainly does.
Arduino Sequencer v1.7 Released!
Ok, Drum Mode has been tested, and seems to work correctly, so it’s time to unleash the latest version of the code to the world!
The only hardware change from v1.6 is to add a SPDT (or DPDT, and ignore one pole) on-off switch, with one leg going to 5V, one going to ground, and the center leg going to pin 4 (you can use something else, but you’ll need to change the code…)
Download the code here: sequencer_1_7.pde
and watch a demo video here:
Tagged arduino, diy, electronics, synthesizers
My first EAGLE schematic
I’ve done plenty of quickie hand-scribbled schematics, and at some point some computer-assisted ones (hell, I have a degree in Computer Engineering, it came up once or twice…). So I decided for the Arduino sequencer, I should do a little schematic using recent tools. EAGLE now runs reasonably on OS X, and for noncommercial/evaluation things, the light version is free.
Here’s a PNG of the schematic (Click for a big version and go easy on me, it’s my first EAGLE file…):
And if you actually want to do something with it, here’s the .sch file.
I’ve represented the Arduino connections and various jacks (MIDI, 1/4″ for clock, etc.) with the pinheader objects which don’t 100% correspond to the Arduino pin numbers. Note that for example, Arduino pin A0 is actually pin 1 of the ANALOG block here. Hopefully that’s not too confusing.
Tagged arduino, eagle, schematics, synthDIY
Diversion – Arduino Sequencer V2
While I’ve reached a “pause point” on the Sound Lab, I decided to revisit the Arduino 8-step MIDI sequencer I built for my presentation at Notacon. There are a number of improvements to be made and bugs to be fixed (for those who were there, you may remember it completely failed for the demo – it worked great during setup, but not the demo itself)
What I plan to do:
- Simplify Panel Wiring – I somewhat ridiculously wired the panel originally. Instead, it’s going to get a 5V bus and a ground bus, which will cut panel-PCB wiring by a lot. I’ll also fix the issue with the MIDI output while I’m at it…
- Add a Clock output/tempo indicator – This will be for sync with the Baby 8 sequencer that I haven’t built yet.
- Properly implement a start/stop button – I originally was going to use an on/off switch, but that didn’t work right in the original design so I scrapped it. Since then, I got some of these LED-equipped lever switches, so it will have “running” and “stopped” indicators as well.
- Switch the PCB to a 276-159, and permanently hardwire it to a Modern Device RBBB – they’re selling 5 RBBB kits for the price of one Arduino Nano – how can I refuse?
I think those are all the major changes in store. Stay tuned!
Penguicon Slides
Here are my slides from the two workshops I led at Penguicon last weekend.
Arduino Workshop:
Circuit-bending and Musical Electronics Workshop:
Tagged arduino, circuitbending, penguicon