Friday, June 22, 2018

Arduino based Random Gate generator--done-works


I have been working on a PCB for my various Arduino projects including the Random Gate Generator...part I is discussed in this post.



ABOUT THE BUILD: I have fab'd up a prototype of a Arduino PCB that tries to be flexible and audio oriented, with accommodations for 6 op amps, and places to jam D/A, jellybean logic and so on. I used it as a home for the random generator.

The idea is to not have to fab up a new board for every Arduino project; most seem to be just Arduinos, DACs, and buffer op amps?

Anyway here's what I came up with:




The breadboard prototype is seen on top with working random gate.

I am starting to copy all the parts to the PCB.  Power supply (PAIA!) (+/- 15V) is in the bottom left.....

An hour or so later: Good news!  It all works!!!!  I have been having fun with this module, might build some more.

Arduino code can be downloaded at GitHub.
https://github.com/cslammy/arduino-random-gate

Schematic--note that after drawing this I added a reset switch that you'll see in the code.  this is so if you change your mind about waiting 5 minutes or whatever for the next on or off you can reset all variables to zero and start again.  To get that done, it's the standard 5V switch HIGH 10K resistor to ground LOW.


Finished and working/populated PCB looks like this--last thing to do is create a front panel and wire in 3.5mm jacks but that's really easy:




I have put on my website the  "nanofactory" PCB you see here yet--sorry to say, there are a few mistakes in the PCB--fixable, but if you take the trouble to get the gerber and have a board made, make sure to read up on the fixes.  I have started to clean it the PCB design, and have already had a new set fab'd, but they are not tested; so I kludged around the issues for what you see here. Update: new fab is still not tested; I used the first nanofactory PCB, with fixed mistakes, for the Synth DVM that's now finished.

The best thing about this: if I want to change what the pots do, add features, change how slowly it can fire a gate etc. no need to rewire or add new parts--just go in and change the code.  Also, there is plenty of I/O left over on the board, so if I want to add things (no idea what but I always think of something?) down the road that's pretty easy as well.

The most remarkable thing about all of this is how easy Arduino CV projects are to think up and do.  Comparators--envelopes--LFOs--displays--and so on--super super easy.  And inexpensive! I may never use a 555 timer again!

Last thing to do is make a front panel for this, which I will fab using PCBWAY in China. That's now done as well.  The lazertran decal process didn't come out 100% clean, don't know why, but it's time to rack this puppy and move on.

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