speed reducer

[TinkerTailor]

20 minutes ago, gigi said:

Thank you for the idea! We need to find a potentiometer with low amplitude movement to work with the pedal or a magnetic sensor.

If you use a sliding pot, the length of the lever arm actuating the pot will effect the slope of the ramp up from min to max speed. The longer the lever arm, the slower it changes from slow to fast. You could make an arm with a couple holes allowing you to tune the pedal ramp up once you figure out a pot with close to the same values as the internal one.  Places like digikey have lots of sliding pototentiometers. They make some really smooth ones for not too much money because they are used in audio applications. They need to work good because when the beats cut out,  the dj gets beer thrown at him...As a matter of fact they make midi bass drum pedals that have the pot built in.....as to building your own,  Tons of choices for a pot under 20 bux, most under 5. .....

And now that i thought about this, here is your solution, sustain pedals for guitar/keyboard, why reinvent the wheel? You could probably use a rockband controller from a garage sale.....

http://www.sweetwater.com/c520--Keyboard_Pedals

Edited November 7, 2016 by TinkerTailor

[TinkerTailor]

10 minutes ago, Sticks said:

Im loving this thread.

How can this be set up to control the pedal lever.?

I kinda have two ideas going there, one is to add a sliding pot to some kind of pedal allowing you to adjust the attacment point. The other is to use/modify an existing electronic pedal from a guitar or keyboard. Or even a domestic sewing machine.

For the first idea, to connect the sliding pot to the pedal, I would use a linkage rod to the pot slider from the pedal or a chain and return spring.

The keyboard pedal option may just be plug and play, as in cut leads to pot on vfd and patch in the pedal. Have to look up a few values to be sure.

[gigi]

So far didn't find a pedal with the exact parameters we need (2200 Ohm). So it might require modifying one.  

[TinkerTailor]

30 minutes ago, Sticks said:

Im loving this thread.

I am as well. I don't go by Tinker for nothing. I am always thinking of things like this. Problem on here is if you make these kinds of suggestions to someone who is too much of a novice, and they are in way over their head, They could very well let the smoke out and electrocute themselves. Never a good thing.... When i find someone of like mind with an obvious foundation of knowledge and access to help if needed, it is fun and refreshing to discuss some kind of weird design......that may be dangerous to man and machine.

[gigi]

Sticks's fault: he asked for photos  ***kidding***.

I will edit the post and remove the photos. You have them on email. 

[Wizcrafts]

For those of you who are thinking about instituting a pot pedal, are you aware of the floor pedal used by pedal steel guitarists?  They are made of aluminum and are fully enclosed. Some, like my Goodrich pedal, have a power jack on the back that uses a standard wall wart converter. Others, like the Hilton, use a different jack for a plus/minus supply. These pedals come up for sale on the Steel Guitar Forum on a regular basis.

 

Here is an ad for a used Goodrich pot pedal for sale.

[gigi]

Thank you for the suggestions! We thought about the floor pedal too (adding this after replacing the clutch motor with a regular one):  just need to find a pedal with the proper resistance. Also would like to keep this solution under a certain cost, otherwise would be more economical to buy a servo.  

[Wizcrafts]

7 hours ago, Sticks said:

How would this be implemented in this case.? 

I don't know how the foot pedal's pot would be connected to the servo motor. That's for the electronics gurus to figure out. My pedal uses a 500k audio log taper long life pot with a sealed carbon element. But, once they come up with a way to have an external pot, as long as the cable can be up to 3 feet long, a steel guitarist's volume pedal makes an excellent enclosure. They pivot very smoothly from the rear and have tension adjustments that can be set to your foot action. I set mine so it stays put wherever I have it when I take my foot off the pedal.

There are 4 screw-on rubber feet to keep the pedal in place.

Anybody pondering this idea needs only to go to your nearest bar that has live Country Music bands that have a steel player. I'm sure he will let you look over his floor volume pedal. If you are in mid-Michigan, look me up for where I'm playing on any given weekend.

[dikman]

TT has a good point about proffering information that could cause problems for someone who doesn't really understand the subject. If you already have a 3-phase motor on your sewing machine then a suitable VFD (particularly if the price is right) could be a viable solution to speed control. However, as Gigi has pointed out, there are problems making speed adjustments on-the-fly unless you have three hands! It will need work to enable speed control via a foot pedal.

If you have a conventional (single-phase) clutch motor then a servo is the only way to go. Fitting a VFD/3-phase setup will be costlier and require additional work, whereas swapping to a servo is a straightforward changeover process.

Gigi also mentioned changing her clutch motor to a "normal" motor, but again unless you can pick up a suitable 3-phase motor cheap (unless you have one lying around) then it would be much simpler to just fit a servo.

[dikman]

Could be a bit tricky to implement, Sticks, but worth trying as basically all it will cost you is time. If it works then fine, if not you (we) will have learned a bit more.