Hi,
I would like to build something for audio controll (volume, eq etc.) and I need to find something like potentiometer or encoder (there are many...) but with motor for load the actual value which may be on the knob. The akcion may be fast just like linear pots on digital mixers (some hunderts of ms). There are some pots, but the speed is somethink like 15° agle/sec... The real controll (volume) will be from some uPC and some ic for volume controll. But I need fast rotary motorized pot/encoder for normal pot controll like any analog machine for audio...
I think small stepped motor can solve this function, but I need real knob with real end to end function (270°) and don'n know, how to measure the actual position of stepped motor...
Any ideas?
Thanks for all answers 🙂
I would like to build something for audio controll (volume, eq etc.) and I need to find something like potentiometer or encoder (there are many...) but with motor for load the actual value which may be on the knob. The akcion may be fast just like linear pots on digital mixers (some hunderts of ms). There are some pots, but the speed is somethink like 15° agle/sec... The real controll (volume) will be from some uPC and some ic for volume controll. But I need fast rotary motorized pot/encoder for normal pot controll like any analog machine for audio...
I think small stepped motor can solve this function, but I need real knob with real end to end function (270°) and don'n know, how to measure the actual position of stepped motor...
Any ideas?
Thanks for all answers 🙂
Or use electronic pots - ICs that perform the pot function. Those can change at digital speed. If you want to be able to control them manually with a knob as well, you could probably use regular pots for a control voltage.
Digital Potentiometer ICs | Mouser
Digital Potentiometer ICs | Mouser
Why do you need a motor? If you have uPC control, interface a rotary encoder with a boutique knob ;-) , read speed/direction and use that to drive the attenuation chip.
That system can be much faster than you turning the knob!
Or do I miss something?
Jan
Yes, as You mentioned, I have some attenuation chip and I can drive them with the encoder (from uPC). But I need te encoder without some leds around, I need the encoder with potentiometer-like control, so It can be normal potentiometer (value change controlled with A/D for example), or encoder, bud not the infinite encoder.
Is that more clear?
Use a normal potmeter with a DC voltage, send the DC voltage to the uC A/D input and use that to drive the atten chip. You will have total control over the atten law.
Jan
That's exactly what I want to do, but I'm looking for a potentiometer with a motor and a "high" rotation speed. As the digital consoles have motorized faders (fast recall of their positions), I need pots with fast rotation recal. It's an untraditional solution, I did not see it on any device. If I select some channel (for example), I need to get the actual position for these knobs for selected channel (instead of lighting some LEDs around).
If you only need a single channel then a dual gang pot backed onto a stepper motor will work. One of the wipers can be used for sensing the current position of the pot.
It is much the same as the system in low cost RC servos, but with the stepper motor the force applied when the motor isn't driven is much more manageable.
If you wanted real fancy then a much more advanced servo like the ones made by Dynamixel can be programmed to act in all sorts of ways.
EDIT- if the pot is only giving out a static DC value for your use anyway, then don't you have the position of the pot already? In that case a single channel pot would already be fine. But I suppose there are more dual gangs out there with a hex already exposed at the back end for you to couple to.
It is much the same as the system in low cost RC servos, but with the stepper motor the force applied when the motor isn't driven is much more manageable.
If you wanted real fancy then a much more advanced servo like the ones made by Dynamixel can be programmed to act in all sorts of ways.
EDIT- if the pot is only giving out a static DC value for your use anyway, then don't you have the position of the pot already? In that case a single channel pot would already be fine. But I suppose there are more dual gangs out there with a hex already exposed at the back end for you to couple to.
Yeah, that's it. I need only the static DC value, only the position of the pot. I got the idea of rotation with potentiometer using bottom hexagon, but I dont know, how the hexagon is robust. A lot of potentiometers (alpha) are relatively stiff in terms of rotation, the force required for rotation is too high, I guess. Thats pretty cool for manual and correct control, but not for fast change of position. I'm worried about the lifetime of this solution, but if any potentiometer can rotate really easy, it would probably be the most ideal solution for me. Any tips for small stepper motors?
I think I have done something that could help you. I only have a pdf scan (it's a VERY old article ;-) so I need an email address to send it, it's to big to add here.
Send me your email via PM.
Jan
Don't bother - I posted it on my website: A motorized remote vol/bal controller | Linear Audio NL
Jan
Jan
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Yeah, logic can be solved by uPC, position from AD converter (8 or 10 bits are sufficient), the system si elegant. I will try to find a suitable potentiometer 🙂 .
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