Arduino ADC question...

[Tony Hardie-Bick]

On 18/10/11 16:39, James Coplin wrote:
> What do you think about the 5v range?  Is it OK to push the max of the
> analog inputs after shifting/attenuating or is there a "better" lower
> upper voltage to shoot for?  Thanks!

I'd probably put it down at 4V and scale in software. If checks with a scope or 
meter showed the circuit could handle the full range, then I'd go over to that, 
after initial success with the reduced range.

Tony (HB)

>
> James R. Coplin
>
> -----Original Message-----
> From: music-bar-bounces at lists.music-bar.org
> [mailto:music-bar-bounces at lists.music-bar.org] On Behalf Of Tony
> Hardie-Bick
> Sent: Tuesday, October 18, 2011 9:37 AM
> To: Music-bar
> Subject: Re: Arduino ADC question...
>
> http://www.ecircuitcenter.com/circuits/opsum/opsum.htm
>
> one of the inputs will be a high reference voltage, the other the bipolar
> CV, choose the resistors so you shift the lowest output to 0V, and if
> necessary add some gain to get the desired signal range.
>
> Put the equations (with separate resistor values for each input) into a
> spreadsheet and tweak :) Keep in mind the gain will be affected by CV
> output impedance unless you buffer it.
>
> Tony (HB)
>
> On 18/10/11 16:28, James Coplin wrote:
>> Thanks Jay, those will be useful in the future.  However, I'm not
>> attempting to output CV, I'm attempting to read an input CV with a
>> negative component.
>>
>> James R. Coplin
>>
>>
>> -----Original Message-----
>> From: music-bar-bounces at lists.music-bar.org
>> [mailto:music-bar-bounces at lists.music-bar.org] On Behalf Of Jay
>> Vaughan
>> Sent: Tuesday, October 18, 2011 9:09 AM
>> To: Music-bar
>> Subject: Re: Arduino ADC question...
>>
>>> I'd ask since I'm not getting a satisfactory answer on the Arduino
>>> forums or elsewhere.
>>
>> Some links about how to do it here:
>>
>> http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1169703529/all
>>
>> And here is a nice schematic:
>>
>> http://tomscarff.tripod.com/cv2midi/cv2midct.gif
>>
>> Look at the yellow section ..
>>
>>
>> ;
>> --
>> Jay Vaughan
>>
>>
>>
>>
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