Whizzer

[jjucius]

Hi
Its been a while but i think they put me back together ok. just got out of the hospital, did bypasses on both legs. but i am going to be building a 5e3 amp and would like to build a whizzer like the one neil young uses. what it is , its a box that sits on top of his amp with servos that turn the knobs on his amp. on his foot board are 3 or 4 push bottons that when he needs a sound for a certin song all he has to do is hit the switch and it turns the knobs on his amp to a predetermend setting. does any one have any idea how to build such an animal?
well i need to lay back down
Thanks
Joe

[A.S.P.]

congrats on your recovery!

[The Tone God]

Great to see you back!

I vaguely remember something about the Whizzer. It sounds like a stepper motors linked to the pots. Probably encoded motors too so the device knows which direction to turn and when to stop. The hardware would be the toughest part. The software would just read the encoders and adjust based on that.

Maybe another way is to buy server controlled pots, not cheap, which are pots that have the motors already connected, connect the pot shafts together then use the servo pot as a position sensor. That would simplify things.

Andrew

[R.G.]

The simplest mechanical way to do it is to get small *double-end-shafted* stepper motors with 1/4" diameter shafts. These can be had in step finenesses up to 200 steps per revolution, or 167 steps for the typical 300 degree shaft motion pot. You want to run the motor from a DC supply that will just turn the pot, not break it when it comes to the pot's rotation limit. Couple the pot to the motor with a bit of 1/4" ID auto fuel hose and stainless steel hose clamps. Use one end of the motor for the pot-turner, and stick the other end out the front of the chassis and put a knob on it. When the motor is off, you get a 167-step stepped pot from the motor's slight cogging. When the motor is on, it turns the pot.

Do the stepping in a PIC. Probably set of drivers per motor getting step/direction signals and a motor enable. When the PIC comes up, have it turn each pot 167 steps counter clockwise to ensure that the pot is at negative limit, record that position as "0" on the pot, and from then keep the pot position in the PIC as a number. Then you can turn the pot by PIC and not lose track of where your pot is, no encoders needed. And you retain manual control if the drivers fail.

The user interface for setting which pots are in which position for Program #17 is the hard part.

[jjucius]

Thanks for your help, and kind words. they went in on both sides of my groin so i'm a little sore yet. i went through hell but one thing good came out of it. the wife feels sorry for me so i talked her into letting me buy the fender 5e3 tweed deluxe kit. ok, i can probly do the mecahanial stuff but not to keen on stepper motor control, so if any one could draw up something that would be great i plan on having foot switches control the motors from my pedal board.
well thanks alot guys
Joe

[The Tone God]

I'll give alittle more detail on my idea. There are pots that have servo motors connected to them. I believe mouser has them. My thinking was you take the pot shaft and mate it with the amp's pot shaft. You can then use the pot on the servo, wired as a variable voltage control, to give the position of the pot's shaft. This can the be read by a uC's A/D and adjusted using standard motor control techniques, as the motor I believe is not be a stepper motor, to the position needed by reading the pot's value. That would actually be pretty simple. The major caveat I could see is if the servo motor is strong enough to turn the amp pot.

Once you get the mechanics like the shaft connection and the electrical portions designed (i.e. power supply, motor controller, presetting storage, foot controller, interfaces, etc.) it really becomes a software thing of reading the A/D from the servo pot and running the motor in the right direction. Alot of this depends on what experience you have. If you don't know software design, uCs, and how to design the electrical portions then this could easily be an overwhelming project.

Andrew

[David]

Joe:

What kind of bypasses?  Coronary?  Did you have blocked arteries in your legs?  Yeowch!  Shades of Dickie Nixon's phlebitis!  That stuff can KILL you, man!
Did they put stents in or something?

Best wishes for your recovery!

[jjucius]

The bypasses were to my legs, my right one was blocked 100% they cleaned it out and put a steint in but it dident hold so they had to bypass. they found blockage in my other leg to so they put a steint in there too. before the surgery my right leg was white. i found all this out around a year ago, and a year before that i had 3 small strokes, that blockage they cant do any thing about because its to far in the brain. besides all that, well high blood pressure, high colestorol, and diebeties im doing perty good.
I think i found a way to build a whizzer, search for midibox. its for control surfaces and they have a motor fader board to control motorized faders, also a digital in board that can have switches hooked to and a core board with a pic chip.
Joe

[potul]

For an application like this one, instead of a stepper motor, could a "hobby servo" motor be used? You don't need any information on position as you tell directly the motor which position you need it to go through the control signal, so no need to reset the position or close the loop with an encoder. The tricky part is I don't know how easy is to get a servo motor with more than 180 degrees range.

Potul

[jjucius]

I was thinking motorized pot's, dosent matter what size in ohms since you would just use them to turn the pots on your amp. i am going to look into it more and will keep you posted.
Joe

[Mark Hammer]

The bypasses were to my legs, my right one was blocked 100% they cleaned it out and put a steint in but it dident hold so they had to bypass. they found blockage in my other leg to so they put a stent in there too. before the surgery my right leg was white. i found all this out around a year ago, and a year before that i had 3 small strokes, that blockage they cant do any thing about because its to far in the brain. besides all that, well high blood pressure, high colestorol, and diebeties im doing perty good.

You realize the stents are made of tantalum?  Of course, as anyone here knows, mylar would give much "cleaner" blood flow than tantalum, with less leakage.   Certainly one of the biggest misconceptions people have about stents and introvascular "clearance" procedures is that all of the crap that was causing the circulatory problem is somehow cleared out.  It isn't.  It never goes away, and sadly our sins stay with us.  All the stents and such do is to pack the crap in a little more tightly against the vascular walls.  Happily, a bit of "repacking" can make a helluva difference in how we feel.

I've had a couple of angioplasties and a triple bypass myself, and Lipitor and Metformin is a big part of my diet these days.
Both sides of the groin?  That means they had to "shave you like a Vegas showgirl".   There are places a man should never have to experience razor stubble, and as one who has been through it I can say that that's one of them.

Funny story.  After I awoke from surgery, my wife and my sister were bedside in Intensive Care.  My wife asked me if there was anything she could get me or anything she could do for me.  I was still way drugged up, and had tubes up the yin-yang (the yin wasn't so bad, but the yang was sheer hell).  I gestured for her to come closer.  When her face was besdie mine, I softly said "Please scratch my balls!  I am sooo itchy.  I can't reach and I can't ask the nurses to do it."  The nurses heard this and practically collapsed laughing on the floor.  My wife, ever the angel, surreptitiously slipped her hand under the blankets, and looking around the room as if to suggest she was interested in things away from my bed, got to work.  It's like they say, it's the little things that count!

Welcome back from the brink.