32-bit Audio Effects Unit

7/29: I printed up a small jig to test pedal sensors. It lets me turn a magnet by hand over the sensor; this helped me pinpoint a not-bug in the position sensor coding. It turns out the AS5055A output is 0-1FFF (13 bits) over 360 degrees; the datasheet must be referring to 12 bits over 180 degrees. Anyhoo, the position sensor is tracking fine now.

7/30: The last bug has been obliterated, all scope waveforms track on all effects - time for the acid test! I hooked up a guitar to the input, and the output to the Aux In jack of a cheapo countertop stereo, and ... a split-second of sound, and <pop> no audio. Power off/on, a split -second of sound, and <pop>. WTF?

I hooked in the oscillator I was testing with, everything's back to normal; at least nothing blew. 'Sample/Hold' and 'Theremin' sound totally *awesome* as you move the magnet! Most of the rest work as expected, but Chorus seems a bit odd; then again, it could be that I'm getting cancelling effects from a single-frequency input tone.

After that, I tried the guitar again - NOW it decides to behave! Maybe I'm sitting too close to the speaker, and feedback tripped something.

All in all, it's working, just not reliably. More testing to come.

8/6: Came across a description of something called 'Track & Hold' in an essay on sample & hold circuits. It is now effect number 16 on the device. Given that the selector is a 12-position encoder, that's 1-1/3 turns of the knob to scroll through the list. I'm declaring a moratorium on new effects until I get some opinions on what to cull. My Carpal Tunnels will thank me later. Plus, as Brian mentioned in the review, I need to focus on the mechanical side of things.

8/11: My first print of a foot pedal mechanism came out with a weak layer through everything; the plastic is pale, with visible gaps between layers. Pieces fall off at the merest touch. Still, it gives me some insight into what might and might not work.

7/12: Ran across a description of a Sample & Hold; 13 lines of code later, I have my 15th effect. I'll have to play with the hold time to find the best sound.

7/22: Well, after a few days tracking down a bug caused by combined misreading of the PIC datasheet AND leaving some test code un-commented-out, I finally saw my waveforms change smoothly in response to the pedal magnet. YES!

Tonight I'm off to the local makerspace (Sask TechWorks) to see about printing a case and components.

7/28: after various fits and starts, I got a 'learning prototype' printed - as in '"now i get to see how bad my Sketchup skills are". :)

Being that it was a flat box, the corners pulled up - oops, lesson learned. And I STILL can't figure out how the Makerbot printed several centimeters of (millimeter-sized) horizontal beams WITH NO SUPPORT STRUCTURE! How'dtheydothat?

made for ergonomics. All in all, for a first pass, I'm satisfied.

Tonight it's back to the 'space for more...