[sdiy] PWM, Vactrols & Opto-Isolators

[Dustin Withers]

Jason,

Thanks for that. I'll be sure to check it out.

-dustin

On Wed, Jan 13, 2010 at 7:14 PM, Jason Proctor <jason at redfish.net> wrote:
> ymmv, but i gave up on the pwm output option and use an SPI DAC instead
> (TLV5618). straightforward to use and works like a champ.
>
> code and circuits etc in the files section of arduino_synth @yahoo.
>
>
>
>> The application is a mix of my own interest and that I've noticed many
>> of these inexpensive micro controller boards have many PWM outs. I'd
>> like to be able to do digital control of analog circuits. It seems my
>> best bet maybe some kind of DAC though, right?
>>
>> dustin
>>
>> On Wed, Jan 13, 2010 at 5:37 PM, Tom Wiltshire <tom at electricdruid.net>
>> wrote:
>>>
>>>  Dustin,
>>>
>>>  If you're looking to get a DC level out, then I'd say, yes, 30KHz is
>>> high.
>>>  You could set the RC filter frequency for 10Hz and the pulses would be
>>> more
>>>  than 3 decades above the cutoff, which ought to give a decent filtering
>>>  action even with such a simple layout.
>>>
>>>  Jay's comment's about linearity are very pertinent though. PWM->LED
>>>  linearity isn't going to be perfect, and LED->LDR linearity will add
>>> it's
>>>  own twist too. How accurate do you need it? What's the application?
>>>
>>>  Regards,
>>>  Tom
>>>
>>>
>>>  On 13 Jan 2010, at 19:03, Dustin Withers wrote:
>>>
>>>>  Tom,
>>>>
>>>>  Is a pulse frequency of 30Khz considered high?
>>>>
>>>>  Thanks for the help,
>>>>  -dustin
>>>
>>>
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