[sdiy] Radio Controlled Synth ?

[Richard Wentk]

On 9 Jul 2007, at 15:40, Tom Wiltshire wrote:

>
> On 9 Jul 2007, at 14:57, Needham, Alan wrote:
>
>> OK, it's not the quickest responding system on the planet ---
>> BUT
>> how fast would you wiggle a joystick ?
>> how fast is a typical, cheap RC servo ?
>> so if it is as crude as nailing a servo onto a pot shaft
>> assuming the pulse rate is about 20ms then a microcontroller
>> could be as quick as one pulse to update to a new value, 2
>> pulses should be plenty. That would be fast enough for most
>> joystick applications, pitch bend, filter mod, etc.
>> It might be fast enough for an RC theremin pitch control :-|
>> 	Alan - now mentally wibbling joysticks
>
> I wasn't wanting to pooh-pooh the idea, just point out the  
> limitations. As you say, it'd be fine for most joystick  
> applications, and would replace any source of slow control  
> voltages. Slow, complex, gently evolving sounds are right up my  
> street, so no problems there.
>
> Personally, I can't stand mechanical solutions, so sticking a servo  
> on a pot shaft wouldn't be my preferred method. I'd either:
> a) Filter the PWM output directly to derive a control voltage  
> proportional to the pulse width
> b) Use a uC to measure the pulse width and interface to some other  
> type of output

It would be a lot simpler to use a radio-MIDI link and a MIDI CV box.

Quite possibly cheaper too.

Richard