Knob to Control Dual Footswitch Pedals? In a semi-weird way?

[Threeleggedyoyo]

Hey guys. I have a DIY question and was hoping someone would point me in the right direction. I tried posting this on another forum and had no luck.

Short version: I'd like to have a small knob on my pedalboard. Spinning it in one direction would send out messages equivalent to taps on one button of a dual footswitch. Spinning it in the other direction would send out messages equivalent to hitting BOTH buttons of a dual footswitch.

Long version / background:

For some time, I've used a Digitech Jamman loopstation to trigger samples live with my feet (usually old movie quotes and such):



This worked, but was a bit bulky, especially when paired with the FSX3 footswitch:



Still, between the two I had my desired functions. Start, stop, pattern up and pattern down. Also, the knob was great for when I needed to jump between far-flung patterns (a twist allowed me to jump 10 patterns or so quickly).

The problem is that this took up a lot of space on my pedalboard. So, I got one of these:



This saved me quite a lot of space, which is awesome. I even modified the FSX3 to lose the extra button. Everything is quite compact. Unfortunately, I lost the functionality of the knob, so I sort of lost the ability to jump around spontaneously, and that sucks.

The answer may well have to be to get a Jamman Stereo (pictured below). But I'd prefer to avoid this.



So here is my question: Is it possible to build a little knob into my FSX3? That would be the ideal solution.

Here is still more detail...

The FSX3 is a 3-button footswitch, but it actually operates the way a normal dual footswitch would. I believe Button 1 sends a sound on the left channel and Button 2 sends one on the right. The third button sends both at once, which Digitech pedals interprets as a third command. In the case of these particular pedals, this amounts to Mode (useless to me and has been removed from my FSX3 to save space), Pattern Up, and Pattern Down, in that order.



So ultimately I'd need a knob that when turned clockwise, sends out signals to the right (like UP above), and when turned clockwise, sends signals to both right and left (like DOWN above).

Is this possible? Is it super hard? Can anyone tell me how to do it or send me in the right direction? If it can be done easily, that would be great. If not, I guess I'd better grab a Jamman Stereo after all.

[PRR]

Welcome to the forum.

What you ask seems simple, but nothing comes to mind.

Your "knob" is surely a rotary encoder. It makes pulses which also imply direction. You can decode this in a computer and do ANYthing you want. The computer can be a $2 PIC. However you have to program it. From the sense of your well-written question, I suspect you know even less about programming $2 PICs than I do. I could, with much hair-pulling, do it in a Basic Stamp, but that's some investment of cash and debugging time. Others here *may* be able to toss-off an algorithm.

Then there's Rube Goldberg approaches. A rotary switch makes pulses. A drag-arm on the shaft moves one way or the other depending on direction of rotation. I've even seen such a contraption recently but dang if I remember where (and maybe someplace obscure like my tractor). The drag-arm could simply pull a micro-switch to cut-off the pulses to one of the two outputs. The drag has to be similar to the micro-switch force, substantial, so might inhibit your "ability to jump around spontaneously", which sucks.

[mth5044]

Sounds like a job for a micro controller as PRR suggests.

But, as a random thought, what If you replaced the switches with transistor switches (or put in parallel with the push switches) and controlled them with a square wave pulsing at the rate that you would want to fly through the settings. Use a rotary switch with the middle being off, flip it one way and you apply your pulses to one of the transistor switches, acting like you are pushing one of the buttons at a certain rate that your pulses are coming in. Flip the switch the other way and apply the pulses to the other transistor switch.