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R-2R attenuator PCB layout question
R-2R attenuator PCB layout question
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Old 24th November 2017, 07:47 PM   #91
OlegSh is offline OlegSh
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R-2R attenuator PCB layout question
Does your chassis look the same as mine from the outside? I plan to get a second one and now am a bit worried to get a "different" kind despite the same external look.
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Old 25th November 2017, 11:33 AM   #92
ElFishi is offline ElFishi  Europe
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looks the same.
the recess is 30mm wide. too much for the 31mm distance of the LCD mounting holes.
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Old 25th November 2017, 12:20 PM   #93
OlegSh is offline OlegSh
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R-2R attenuator PCB layout question
On mine the recess measures 25mm wide. I should probably buy the second chassis from the same vendor where I bought the first one and hope that I'll get the same 25mm wide recess. On the other hand, I plan to make myself a present and buy a 3D printer in the near future, and later the CNC router. Their prices are now down to around 300 Euro compared to 600Euro half a year ago, so both became more affordable. Then I'll be able to customize any chassis to my liking.

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Oleg
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Old 25th November 2017, 04:55 PM   #94
ElFishi is offline ElFishi  Europe
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bought from doukmall, have you seen a different vendor for DE?
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Old 25th November 2017, 05:19 PM   #95
OlegSh is offline OlegSh
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R-2R attenuator PCB layout question
I've got mine in January this year from the other vendor directly from China for 25 Euro (delivered). Same vendor now ships from Bremen as all other vendors and asks 48 Euro for the same chassis. So I guess I am out of luck.
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Old 30th November 2017, 01:53 PM   #96
Morde is offline Morde  Finland
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Hi Oleg.

Iíve got my attenuator up and running. Just one problem left. The Chinese rotary encoder board that Iím using only adjusts volume step up/down on every other incerement. I think there was some parameter in the code that could be adjusted. Should I try it?
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Old 30th November 2017, 06:13 PM   #97
OlegSh is offline OlegSh
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R-2R attenuator PCB layout question
Hi Martti,

Yes, you can adjust the code to suit your encoder. I used an encoder with 64 pulses per revolution. Each pulse is 4 state changes thus allows theoretically up to 256 attenuation steps. I needed only 32 attenuation steps and wanted them to complete in one full turn of the encoder and thus I divided the total number of state changes by 8. In the last version of the firmware (see post #79) on lines 15 and 16 I introduced two variables EncoderResolution and MAXAttenuation which you can modify to suit your setup.

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Oleg
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Old 1st December 2017, 07:27 AM   #98
Morde is offline Morde  Finland
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Thanks Oleg.

The encoder I have has only 20 pulses per revolution which means according to your instructions 4*20 = 80 state changes. But the attenuator has 32 steps, so I just set 4*32 = 128: "EncoderResolution = 128 - 1". This means that the encoder rotates more than one full circle, but I don't mind. Works just fine.
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Old 1st December 2017, 07:44 AM   #99
OlegSh is offline OlegSh
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R-2R attenuator PCB layout question
Great! In principle there are cheap 15 pulses/30 detents per revolution mechanical encoders similar to your. They also cost about the same. So if making 1.5 turns for full volume is inconvenient you can simply get a 15 pulses/30 detents version. Then you can configure the controller for 30 attenuation steps per revolution using 2 state changes per detent instead of 4. If you want to try it I'll be happy to help to modify the code accordingly if you'll get difficulties with it.

Regards,
Oleg
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