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Threetwosevensixseven
Joined: May 29, 2004 Posts: 11 Location: Oxford, UK
G2 patch files: 2
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Posted: Sat May 29, 2004 9:09 am Post subject:
13 Segment LED |
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This is my first post to this board and first shared G2 performance (x-posted to the NM list). Hi folks!
This performance has given me a lot of fun over the last week, as well as (literally!) a couple of really bad headaches. It is also a possible contender for the least-useful patch yet, since it produces no sound at all! (Although I'm hoping to get some interesting control structures out of the logic, but no more on that for now.)
You have to squint quite carefully (sorry guys) at the matrix of LEDs formed by the pink bank of A/D converters in slot A. If you do, hopefully you will make out two digits, which display the value of the blue constant knob above. It works when the constant knob is unipolar, and bipolar in the +ve range only.
For tidyness I put the user interface in slot A, and the logic in slot B, using CCsends for inter-slot communication. The whole thing came out of me realising I don't know much digital logic, and starting to teach myself with quite a nice book (Digital Fundamentals, Floyd). My brain was exploding with Nord possibilities by the time I reached the chapter on Karnaugh mapping, so I made a 13-segment LED circuit using as a minimised sum of products, and then just for fun made the right digit as a minimised product of sums, which ended up being slightly efficient. I made quite a few initial mistakes in the SOP one which were much harder to correct after the event, so I guess it could be optimised more.
I got a bit stuck over how to decode the control signal into two BCD digits (whether to attempt clocked dividers!) but this evening in a burst of inspiration decided analogue was better! a linear mixer at 10.2 does an adequate divide by ten, and two mixers do a nice multiply by ten (add ten times, seemingly more accurate than trying to multiply with amplifiers or gain controls). Interestingly, dividing a control signal by ten then multiplying by ten does give the original value, proving there are intermediate steps between each (32768, Rob H said in his tutorials?). But you can get an integer (or is it rounding?) using an AD/DA pair, then just multiply that by ten again and subtract it from the original, which gives you the right hand digit.
Cheers, Robin
Threetwosevensixseven
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LED Display_2.prf2 |
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mosc
Site Admin
Joined: Jan 31, 2003 Posts: 18195 Location: Durham, NC
Audio files: 211
G2 patch files: 60
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Threetwosevensixseven
Joined: May 29, 2004 Posts: 11 Location: Oxford, UK
G2 patch files: 2
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Posted: Sun May 30, 2004 2:52 am Post subject:
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Thanks Howard
Screenshot, good idea, I should have thought of that.
Looks like you have made something pretty nice here with your board and the Nord forums...
Cheers, Robin |
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mosc
Site Admin
Joined: Jan 31, 2003 Posts: 18195 Location: Durham, NC
Audio files: 211
G2 patch files: 60
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Posted: Sun May 30, 2004 6:31 am Post subject:
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Thank you, Robin. |
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blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24075 Location: The Netherlands, Enschede
Audio files: 277
G2 patch files: 320
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Posted: Sun May 30, 2004 7:55 am Post subject:
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Threetwosevensixseven wrote: |
Screenshot, good idea, I should have thought of that.
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A good idea indeed, as my initial thoughts were that you somehow displayed the numbers on the external LEDs of the keyboard version of the G2. The screenshot made me have a closer look at the patch.
It's nice to see that the G2 can be used as a logic experimentation platform the way you did. When I was still at school and had to learn about Karnaugh diagrams & stuff it was a lot of paper work to experiment and after that some very weird looking APL programming was needed to see whether it would work.
Jan. |
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