Commenting so I can get back to this. Have an expression pedal for a UV-1 that is a little loose and sloppy. Could be the trick.

 

Older "road race" ganes for the PC generally came with a floor unit that was a pair of spring-loaded foot treadles, controlling 50k pots. The uniot would plug into your games port on the back of the computer. They're not exactly high-end, but they can be made into serviceable expression pedals, and can be found for pennies on the dollar, relative to their original retail price. Keep your eyes peeled for them at yard sales and Value Village.

 

That’s pretty good. I think I will try that.

I bought a Roland DP-10 damper pedal and some parts to make an adapter to swap the tip and ring.

I haven’t got around to doing that yet, and then another DP-10 came up cheap on Kijiji, so I bought that and plan to rewire it.

The DP-10 and some other damper pedals have a half-damper feature, which is implemented differently depending on the pedal. Most damper pedals are just momentary switches, and some that do half-damper use one or more resistors so the output jumps up in steps, but for the DP-10 they just made it the same as an expression pedal.

[The DP-10 has a switch to use the pedal as a momentary switch.]

Some effects units can be set to interpret the pedal in reverse, so 0 is 100 and 100 is 0.

DP-10

I saw some pedal brand was using damper pedals to house their effects.

Gamechanger Plus Pedal

I think damper pedals would be nicer to use on stage. You could have them below and extending past your pedal board.

Or maybe one of those pedal keyboards triggering patch changes. There are two on the local Kijiji. I’ve always wanted one, so hard to resist.

 

Most damper pedals are just momentary switches, and some that do half-damper use one or more resistors so the output jumps up in steps, but for the DP-10 they just made it the same as an expression pedal.

Cool. So it has a potentiometer? Do you know what value? Most exp pedals are 10k or 20k linear but of course you can use a higher value pot with a resistor to get in the ballpark.

Does the DP10 have enough travel to control smoothly like a wah?

Some effects units can be set to interpret the pedal in reverse, so 0 is 100 and 100 is 0.

Or if not you can just reverse two wires inside to make it work in the direction you want.

 

It seems to be a 10K pot. On one pedal it swings from 10K to 300 ohms, and on the other it swings from 8.5K to 150 ohms. Interestingly the travel it uses is only about 30°.

It has been a while since I tried it, but I thought it was pretty controllable. Let me get back to you!

Here are some pictures. It’s a DP-10, but the pot is mounted to a DP-8 board. I didn’t notice what the other board with the switch is labelled. White is the tip-wiper, red is the ring, black is the sleeve. I have to swap red and black to make it work, right? It has a very hefty spring. Also, the Neutrik parts to make my adaptor, an NM3P modular stereo plug and the jack part of an NJ3FC6, you have to solder the wires to the NM3P, then screw the parts together, then wire the cartridge for the NJF3C6 and then secure that in place with a little screw.

I think I will do this tonight.

 

I got the pedal polarity reversed.

The control is only pretty good. I can read the position from 0 to 100 on my effect pedal, it seems that on one pedal it jumps from 0 to about 10 pretty quickly, the pedal I didn’t reverse jumps from 100 to 96. On a wah sound you get a noticable jump or click. It’s pretty good for swells, though. I tried seeing if I could stop the pedal at some number, I was not often really close.

The other board says DP-8 as well, DP-8 switch board. There are a lot of missing components on the board! There is room for many resistors and diodes, probably so it can do steps like some pedals have, but all that is on the board is a couple of switches.

There’s a momentary switch for when the it is in switch mode. It’s weird, it is soldered to the board, I think pretty solidly, but relies on the board mechanically, that the board fits in across the whole depth of the pedal.

There’s a DPDT switch in there to toggle it from switch to continuous. I found that in some situations it would be better to work with the original polarity, and since I will not likely be using the pedal in switch mode, it would be nice to change the function to polarity. I think it could be done.

The adaptor isn’t going to well. The right way of putting it together, I think now, is to solder the jack’s cartridge, use short, thin wires, run the wires through the jack’s case, then solder the plug, leave the enough wire so you can screw the plug on and not spin the cartridge, then push the catridge in place and fasten it.

The way I had tried to do it, there is too much wire to fit in the housing and the wires are getting pinched and shorting.

I will try again!

...

The little wires worked. The screw that hold the jack insert in place is metal and it needs to be nylon. I think I remember reading about that.